Статті в журналах: "Patterson River Region (Vic)"

1

Wang, Yuqian, Xiaoli Yang, Mengru Zhang, Linqi Zhang, Xiaohan Yu, Liliang Ren, Yi Liu, Shanhu Jiang, and Fei Yuan. "Projected Effects of Climate Change on Future Hydrological Regimes in the Upper Yangtze River Basin, China." Advances in Meteorology 2019 (January 14, 2019): 1–14. http://dx.doi.org/10.1155/2019/1545746.

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Climate change directly impacts the hydrological cycle via increasing temperatures and seasonal precipitation shifts, which are variable at local scales. The water resources of the Upper Yangtze River Basin (UYRB) account for almost 40% and 15% of all water resources used in the Yangtze Basin and China, respectively. Future climate change and the possible responses of surface runoff in this region are urgent issues for China’s water security and sustainable socioeconomic development. This study evaluated the potential impacts of future climate change on the hydrological regimes (high flow (Q5), low flow (Q95), and mean annual runoff (MAR)) of the UYRB using global climate models (GCMs) and a variable infiltration capacity (VIC) model. We used the eight bias-corrected GCM outputs from Phase 5 of the Coupled Model Intercomparison Project (CMIP5) to examine the effects of climate change under two future representative concentration pathways (RCP4.5 and RCP8.5). The direct variance method was adopted to analyze the contributions of precipitation and temperature to future Q5, Q95, and MAR. The results showed that the equidistant cumulative distribution function (EDCDF) can considerably reduce biases in the temperature and precipitation fields of CMIP5 models and that the EDCDF captured the extreme values and spatial pattern of the climate fields. Relative to the baseline period (1961–1990), precipitation is projected to slightly increase in the future, while temperature is projected to considerably increase. Furthermore, Q5, Q95, and MAR are projected to decrease. The projected decreases in the median value of Q95 were 21.08% to 24.88% and 16.05% to 26.70% under RCP4.5 and RCP8.5, respectively; these decreases were larger than those of MAR and Q5. Temperature increases accounted for more than 99% of the projected changes, whereas precipitation had limited projected effects on Q95 and MAR. These results indicate the drought risk over the UYRB will increase considerably in the future.

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Wang, Yuan, Wengang Zheng, Hongwei Xie, Qi Liu, and Jiahua Wei. "Study on Runoff Simulation of the Source Region of the Yellow River and the Inland Arid Source Region Based on the Variable Infiltration Capacity Model." Sustainability 12, no. 17 (August 28, 2020): 7041. http://dx.doi.org/10.3390/su12177041.

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Hydrological process simulation and rainfall–runoff analysis are important foundations for reasonably evaluating changes in water resources. In this paper, the VIC (Variable Infiltration Capacity) hydrological model was used to simulate runoff without observed data for exploring the applicability of the model in the Kequ, Dari, and Jimai river basins in the source region of the Yellow River, and the Balegen River basin in the inland arid source region. The results show that, from 2015 to 2018, the VIC model had a good simulation effect. The Nash efficiency coefficients (NSE) of the four basins were all above 0.7, and the NSE of the Dari River basin reached 0.93. The relative error (RE) of the three river basins was about 5%, on average, and the RE of the Balegen basin was 6.50%, indicating that the model has good applicability in the study area. Climate perturbation experiments were performed to quantitatively analyze the relationship between rainfall and runoff. The results show that, in the source area of the Yellow River, rainfall and runoff are roughly linearly related. However, in the inland arid source area, temperature has a slightly greater impact on runoff than rainfall.

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Li, Sisi, Mingliang Liu, Jennifer C. Adam, Huawei Pi, Fengge Su, Dongyue Li, Zhaofei Liu, and Zhijun Yao. "Contribution of Snow-Melt Water to the Streamflow over the Three-River Headwater Region, China." Remote Sensing 13, no. 8 (April 19, 2021): 1585. http://dx.doi.org/10.3390/rs13081585.

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Snowmelt water is essential to the water resources management over the Three-River Headwater Region (TRHR), where hydrological processes are influenced by snowmelt runoff and sensitive to climate change. The objectives of this study were to analyse the contribution of snowmelt water to the total streamflow (fQ,snow) in the TRHR by applying a snowmelt tracking algorithm and Variable Infiltration Capacity (VIC) model. The ratio of snowfall to precipitation, and the variation of the April 1 snow water equivalent (SWE) associated with fQ,snow, were identified to analyse the role of snowpack in the hydrological cycle. Prior to the simulation, the VIC model was validated based on the observed streamflow data to recognize its adequacy in the region. In order to improve the VIC model in snow hydrology simulation, Advanced Scanning Microwave Radiometer E (ASMR-E) SWE product data was used to compare with VIC output SWE to adjust the snow parameters. From 1971 to 2007, the averaged fQ,snow was 19.9% with a significant decreasing trend over entire TRHR (p < 0.05).The influence factor resulted in the rate of change in fQ,snow which were different for each sub-basin TRHR. The decreasing rate of fQ,snow was highest of 0.24%/year for S_Lantsang, which should be due to the increasing streamflow and the decreasing snowmelt water. For the S_Yangtze, the increasing streamflow contributed more than the stable change of snowmelt water to the decreasing fQ,snow with a rate of 0.1%/year. The April 1 SWE with the minimum value appearing after 2000 and the decreased ratio of snowfall to precipitation during the study period, suggested the snow solid water resource over the TRHR was shrinking. Our results imply that the role of snow in the snow-hydrological regime is weakening in the TRHR in terms of water supplement and runoff regulation due to the decreased fQ,snow and snowfall.

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4

Lobmeyr, M., D. Lohmann, and C. Ruhe. "An application of a large scale conceptual hydrological model over the Elbe region." Hydrology and Earth System Sciences 3, no. 3 (September 30, 1999): 363–74. http://dx.doi.org/10.5194/hess-3-363-1999.

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Abstract. This paper investigates the ability of the VIC-2L model coupled to a routing model to reproduce streamflow in the catchment of the lower Elbe River, Germany. The VIC-2L model, a hydrologically-based land surface scheme (LSS) which has been tested extensively in the Project for Intercomparison of Land-surface Parameterization Schemes (PILPS), is put up on the rotated grid of 1/6 degree of the atmospheric regional scale model (REMO) used in the Baltic Sea Experiment (BALTEX). For a 10 year period, the VIC-2L model is forced in daily time steps with measured daily means of precipitation, air temperature, pressure, wind speed, air humidity and daily sunshine duration. VIC-2L model output of surface runoff and baseflow is used as input for the routing model, which transforms modelled runoff into streamflow, which is compared to measured streamflow at selected gauge stations. The water balance of the basin is investigated and the model results on daily, monthly and annual time scales are discussed. Discrepancies appear in time periods where snow and ice processes are important. Extreme flood events are analyzed in more dital. The influence of calibration with respect to runoff is examined.

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Jin, Junliang, Guoqing Wang, Jianyun Zhang, Qinli Yang, Cuishan Liu, Yanli Liu, Zhenxin Bao, and Ruimin He. "Impacts of climate change on hydrology in the Yellow River source region, China." Journal of Water and Climate Change 11, no. 3 (September 3, 2018): 916–30. http://dx.doi.org/10.2166/wcc.2018.085.

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Abstract Variations of precipitation, temperature, and runoff in the Yellow River source region were analyzed with the Mann–Kendall and Spearman rank correlation tests over the past 60 years. Based on the seven climate scenarios from CMIP5 climate models under RCP2.6, RCP4.5, and RCP8.5, responses of hydrological process to climate change were simulated using the Variable Infiltration Capacity (VIC) model. Variation analysis results indicated that recorded temperature presented significant increasing trend. Daily minimum temperature presented higher increasing trend than daily maximum temperature. Annual gross precipitation presented minor increasing and annual runoff presented minor decreasing. The VIC model performed well on simulating monthly discharge at Tangnaihai station, with NSE of 0.91 and 0.93 in calibration and validation periods, respectively. The projected annual mean temperature would rise (with 25th and 75th percentiles) 1.07–1.32 °C, 1.76–2.33 °C, 3.45–4.29 °C, annual precipitation is expected to increase 3.43%–11.77%, 8.05%–17.27%, 12.84%–27.89%, and runoff would moderately increase with high variability of 0.82%–14.26%, −3.41%–19.14%, 1.43%–38.26% relative to the baseline of 1961–1990 under each RCP in the 2080s, respectively. The inhomogeneity of runoff may increase in the future. Many more droughts and floods under climate change may threaten social development in this region in the future.

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6

Santana-Cornélio, Gilcilene, Elciomar Araújo-de-Oliveira, Keila Magalhães-Xavier, Gabriela Wemilly Barros-da-Silva, Luis Reginaldo Ribeiro Rodrigues, and Emil José Hernández-Ruz. "The genetic structure of Pristimantis latro (Anura: Craugastoridae) mirrors traits of their life history." Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 44, no. 172 (September 29, 2020): 729–39. http://dx.doi.org/10.18257/raccefyn.956.

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One of the main hypotheses to explain the origin of Amazonian diversity is the barrier effect of the rivers known as the riverine-barrier hypothesis, which suggests that riverine barriers isolated once continuous populations leading to differentiation and speciation. In this context, we studied the genetic structure of Pristimantis latro, a newly described species that inhabits a region under marked anthropic pressure due to expansive livestock, illegal mining, and hydroelectric dam construction. The DNA was extracted from 52 P. latro individuals and then amplified via polymerase chain reaction (PCR) using the mitochondrial 16S rRNA and COI markers. To infer the time of divergence between the P. latro localities, we built a species tree and performed an analysis of molecular variance (AMOVA) to infer the genetic differentiation between and within the P. latro populations. We found that P. latro has a marked genetic structure in the populations of the right and left margins of the Xingu River and within the Tapajós-Xingu and Xingu-Tocantins interfluvial regions and that the time of divergence between the populations of the East and West banks of the Xingu River occurred approximately 380,000 years ago. This pattern of genetic structure corresponds to that reported in recent articles for the Pristimantis genus evidencing that species without tadpoles exhibit a genetic structure explained by the hypothesis of rivers as barriers.

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7

Stephen, H., S. Ahmad, T. C. Piechota, and C. Tang. "Relating surface backscatter response from TRMM Precipitation Radar to soil moisture: results over a semi-arid region." Hydrology and Earth System Sciences Discussions 6, no. 5 (October 22, 2009): 6425–54. http://dx.doi.org/10.5194/hessd-6-6425-2009.

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Abstract. The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σ°) of the surface. σ° is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σ° primarily depends on the soil water content. In this study we relate TRMMPR σ° measurements to soil water content (ms) in Lower Colorado River Basin (LCRB). σ° dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σ° that couples incidence angle, ms, and NDVI is used to derive parameters and retrieve soil water content. The calibration and validation of this model are performed using simulated and measured ms data. Simulated ms is estimated using Variable Infiltration Capacity (VIC) model whereas measured ms is acquired from ground measuring stations in Walnut Gulch Experimental Watershed (WGEW). σ° model is calibrated using VIC and WGEW ms data during 1998 and the calibrated model is used to derive ms during later years. The temporal trends of derived ms are consistent with VIC and WGEW ms data with correlation coefficient (R) of 0.89 and 0.74, respectively. Derived ms is also consistent with the measured precipitation data with R=0.76. The gridded VIC data is used to calibrate the model at each grid point in LCRB and spatial maps of the model parameters are prepared. The model parameters are spatially coherent with the general regional topography in LCRB. TRMMPR σ° derived soil moisture maps during May (dry) and August (wet) 1999 are spatially similar to VIC estimates with correlation 0.67 and 0.76, respectively. This research provides new insights into Ku-band σ° dependence on soil water content in the arid regions.

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Stephen, H., S. Ahmad, T. C. Piechota, and C. Tang. "Relating surface backscatter response from TRMM precipitation radar to soil moisture: results over a semi-arid region." Hydrology and Earth System Sciences 14, no. 2 (February 5, 2010): 193–204. http://dx.doi.org/10.5194/hess-14-193-2010.

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Abstract. The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σ°) of the surface. σ° is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σ° primarily depends on the soil water content. In this study we relate TRMMPR σ° measurements to soil water content (ms) in the Lower Colorado River Basin (LCRB). σ° dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σ° that couples incidence angle, ms, and NDVI is used to derive parameters and retrieve soil water content. The calibration and validation of this model are performed using simulated and measured ms data. Simulated ms is estimated using the Variable Infiltration Capacity (VIC) model and measured ms is acquired from ground measuring stations in Walnut Gulch Experimental Watershed (WGEW). σ° model is calibrated using VIC and WGEW ms data during 1998 and the calibrated model is used to derive ms during later years. The temporal trends of derived ms are consistent with VIC and WGEW ms data with a correlation coefficient (R) of 0.89 and 0.74, respectively. Derived ms is also consistent with the measured precipitation data with R=0.76. The gridded VIC data is used to calibrate the model at each grid point in LCRB and spatial maps of the model parameters are prepared. The model parameters are spatially coherent with the general regional topography in LCRB. TRMMPR σ° derived soil moisture maps during May (dry) and August (wet) 1999 are spatially similar to VIC estimates with correlation 0.67 and 0.76, respectively. This research provides new insights into Ku-band σ° dependence on soil water content in the arid regions.

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9

Alvarenga, Lívia Alves, Vinícius Siqueira Oliveira Carvalho, Vinícius Augusto de Oliveira, Carlos Rogério de Mello, Alberto Colombo, Javier Tomasella, and Pâmela Aparecida Melo. "Hydrological simulation with SWAT and VIC Models in the Verde River Watershed, Minas Gerais." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 15, no. 4 (July 6, 2020): 1. http://dx.doi.org/10.4136/ambi-agua.2492.

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Successful streamflow forecasts depend on an adequate performance evaluation of the hydrological model. In this study, the hydrological responses were compared using two hydrological models, physic-based and semi-distributed, Soil and Water Assessment Tool (SWAT) and Variable Infiltration Capacity (VIC), using input data from the Verde River Watershed, located in the Minas Gerais state in southern Brazil. This is a study of one of the most important headwater watershed regions of Brazil (Mantiqueira Range). Both models were suitable for streamflow simulation, with values of R2 (determination coefficient) and NSE (Nash-Sutcliffe) higher than 0.8, NSELog higher than 0.35 (Nash–Sutcliffe Efficiency of the logarithmic values of discharge) and PBIAS (percentage deviation) less than 25%. The integration of SWAT and VIC models can be useful in different water-resource assessment studies. Therefore, based upon this study further investigations should be conducted using various hydrological models and climate, land-use and land-cover changes scenarios in the region.

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10

Wang, Zhaoli, Jiachao Chen, Chengguang Lai, Ruida Zhong, Xiaohong Chen, and Haijun Yu. "Hydrologic assessment of the TMPA 3B42-V7 product in a typical alpine and gorge region: the Lancang River basin, China." Hydrology Research 49, no. 6 (July 9, 2018): 2002–15. http://dx.doi.org/10.2166/nh.2018.024.

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Abstract To evaluate the accuracy and applicability of the TMPA 3B42-V7 precipitation product for the Lancang River basin, we used different statistical indices to explore the performance of the product in comparison to gauge data. Then, we performed a hydrologic simulation using the Variable Infiltration Capacity (VIC) hydrological model with two scenarios (Scenario I: streamflow simulation using gauge-calibrated parameters; Scenario II: streamflow simulation using 3B42-V7-recalibrated parameters) to verify the applicability of the product. The results of the precipitation analysis show good accuracy of the V7 precipitation data. The accuracy increases with the increase of both space and time scales, while time scale increases cause a stronger effect. The satellite can accurately measure most of the precipitation but tends to misidentify non-precipitation events as light precipitation events (<1 mm/day). The results of the hydrologic simulation show that the VIC hydrological model has good applicability for the Lancang River basin. However, 3B42-V7 data did not perform as well under Scenario I with the lowest Nash–Sutcliffe coefficient of efficiency (NSCE) of 0.42; Scenario II suggests that the error drops significantly and the NSCE increases to 0.70 or beyond. In addition, the simulation accuracy increases with increased temporal scale.

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11

Curry, Charles L., and Francis W. Zwiers. "Examining controls on peak annual streamflow and floods in the Fraser River Basin of British Columbia." Hydrology and Earth System Sciences 22, no. 4 (April 16, 2018): 2285–309. http://dx.doi.org/10.5194/hess-22-2285-2018.

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Abstract. The Fraser River Basin (FRB) of British Columbia is one of the largest and most important watersheds in western North America, and home to a rich diversity of biological species and economic assets that depend implicitly upon its extensive riverine habitats. The hydrology of the FRB is dominated by snow accumulation and melt processes, leading to a prominent annual peak streamflow invariably occurring in May–July. Nevertheless, while annual peak daily streamflow (APF) during the spring freshet in the FRB is historically well correlated with basin-averaged, 1 April snow water equivalent (SWE), there are numerous occurrences of anomalously large APF in below- or near-normal SWE years, some of which have resulted in damaging floods in the region. An imperfect understanding of which other climatic factors contribute to these anomalously large APFs hinders robust projections of their magnitude and frequency. We employ the Variable Infiltration Capacity (VIC) process-based hydrological model driven by gridded observations to investigate the key controlling factors of anomalous APF events in the FRB and four of its subbasins that contribute nearly 70 % of the annual flow at Fraser-Hope. The relative influence of a set of predictors characterizing the interannual variability of rainfall, snowfall, snowpack (characterized by the annual maximum value, SWEmax), soil moisture and temperature on simulated APF at Hope (the main outlet of the FRB) and at the subbasin outlets is examined within a regression framework. The influence of large-scale climate modes of variability (the Pacific Decadal Oscillation (PDO) and the El Niño–Southern Oscillation – ENSO) on APF magnitude is also assessed, and placed in context with these more localized controls. The results indicate that next to SWEmax (univariate Spearman correlation with APF of ρ^ = 0.64; 0.70 (observations; VIC simulation)), the snowmelt rate (ρ^ = 0.43 in VIC), the ENSO and PDO indices (ρ^ = −0.40; −0.41) and (ρ^ = −0.35; −0.38), respectively, and rate of warming subsequent to the date of SWEmax (ρ^ = 0.26; 0.38), are the most influential predictors of APF magnitude in the FRB and its subbasins. The identification of these controls on annual peak flows in the region may be of use in understanding seasonal predictions or future projected streamflow changes.

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12

Kassian, Lucy Msigwa, Moses Tenywa, Emma T. Liwenga, Kate Wellard Dyer, and Yazidhi Bamutaze. "Implication of climate change and variability on stream flow in Iringa region, Tanzania." Journal of Water and Climate Change 8, no. 2 (November 15, 2016): 336–47. http://dx.doi.org/10.2166/wcc.2016.238.

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This paper investigates the implication of climate change and variability on the river flow within the traditional irrigation farming system, vinyungu, in Iringa region, Tanzania. The study aimed at establishing areas that are most impacted by climate change in terms of river flow and various adaptation strategies. It is based on both primary data collected by questionnaires distributed randomly among 189 farmers and key informant checklists conducted with villages’ leaders and Agriculture Extension Officers. Two focused group discussions were carried out for each village as well as the researcher's own observations, and secondary data includes: literature review, rainfall and river flow data. The long-term annual trends of rainfall and river flow were analyzed via Mann–Kendall's statistical test and linear trend analysis. Climate data on rainfall trend showed a significant decreasing pattern during the last 17 years. Also, river flow data showed a slight decline within the same period. Decrement in river flow, combined with rainfall fluctuation, forced farmers to employ various adaptation strategies. Following the severity of the problem the paper recommends that more research be conducted on proper water management for sustainable river flow for both agriculture production and environmental management.

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Naha, Shaini, Praveen K. Thakur, and S. P. Aggarwal. "Hydrological Modelling and data assimilation of Satellite Snow Cover Area using a Land Surface Model, VIC." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 353–60. http://dx.doi.org/10.5194/isprs-archives-xli-b8-353-2016.

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The snow cover plays an important role in Himalayan region as it contributes a useful amount to the river discharge. So, besides estimating rainfall runoff, proper assessment of snowmelt runoff for efficient management and water resources planning is also required. A Land Surface Model, VIC (Variable Infiltration Capacity) is used at a high resolution grid size of 1 km. Beas river basin up to Thalot in North West Himalayas (NWH) have been selected as the study area. At first model setup is done and VIC has been run in its energy balance mode. The fluxes obtained from VIC has been routed to simulate the discharge for the time period of (2003-2006). Data Assimilation is done for the year 2006 and the techniques of Data Assimilation considered in this study are Direct Insertion (D.I) and Ensemble Kalman Filter (EnKF) that uses observations of snow covered area (SCA) to update hydrologic model states. The meteorological forcings were taken from 0.5 deg. resolution VIC global forcing data from 1979-2006 with daily maximum temperature, minimum temperature from Climate Research unit (CRU), rainfall from daily variability of NCEP and wind speed from NCEP-NCAR analysis as main inputs and Indian Meteorological Department (IMD) data of 0.25 °. NBSSLUP soil map and land use land cover map of ISRO-GBP project for year 2014 were used for generating the soil parameters and vegetation parameters respectively. The threshold temperature i.e. the minimum rain temperature is -0.5°C and maximum snow temperature is about +0.5°C at which VIC can generate snow fluxes. Hydrological simulations were done using both NCEP and IMD based meteorological Forcing datasets, but very few snow fluxes were obtained using IMD data met forcing, whereas NCEP based met forcing has given significantly better snow fluxes throughout the simulation years as the temperature resolution as given by IMD data is 0.5°C and rainfall resolution of 0.25°C. The simulated discharge has been validated using observed data from BBMB (Bhakra Beas Management Board) and coefficient of Correlation(R2) measured for (2003-2006) was 0.67 and 0.61 for the year 2006.But as VIC does not consider snowmelt runoff as a part of the total discharge, snowmelt runoff has been estimated for the simulation both with and without D.A. The snow fluxes as generated from VIC gives basin average estimates of Snow Cover, SWE, Snow Depth and Snow melt. It has been observed to be overestimated when model predicted snow cover is compared with MODIS SCA of 500 m resolution from MOD10A2 for each year. So MODIS 8-day snow cover area has been assimilated directly into the model state as well as by using EnKF after every 8 days for the year 2006.D.I Technique performed well as compared to EnKF. R2 between Model SCA and MODIS SCA is estimated as 0.73 after D.I with Root Mean Square Error (RMSE) of +0.19. After direct Insertion of D.A, SCA has been reduced comparatively which resulted in 7% reduction of annual snowmelt contribution to total discharge.The assimilation of MODIS SCA data hence improved the snow cover area (SCA) fraction and finally updated other snow components.

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14

Wu, Z., Y. Mao, G. Lu, and J. Zhang. "Simulation of soil moisture for typical plain region using the Variable Infiltration Capacity model." Proceedings of the International Association of Hydrological Sciences 368 (May 6, 2015): 215–20. http://dx.doi.org/10.5194/piahs-368-215-2015.

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Abstract. Droughts have a severe impact on the development of the social economy in developed plain areas. Soil moisture is a good index, it can reasonably reflect changes in drought. In this study, Jiangsu province in the Yangtze River Plain was selected as the research region, and the VIC (Variable Infiltration Capacity) large-scale hydrological model was selected to simulate the daily soil moisture with a resolution of 0.125 × 0.125 degree from 1956 to 2009. The simulated soil moisture was verified by measured soil moisture. The results indicate that the simulated soil moisture distribution is relatively consistent for the three soil layers (0–20, 20−100 and 0–100 cm), showing an increasing trend from northwest to southeast. The simulated soil moisture anomalies agreed well with in situ observations. The simulated soil moisture data thus can be used to analyze the spatio-temporal variation of the regional water content and to provide support for drought monitoring and forecasting.

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15

Naha, Shaini, Praveen K. Thakur, and S. P. Aggarwal. "Hydrological Modelling and data assimilation of Satellite Snow Cover Area using a Land Surface Model, VIC." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 353–60. http://dx.doi.org/10.5194/isprsarchives-xli-b8-353-2016.

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The snow cover plays an important role in Himalayan region as it contributes a useful amount to the river discharge. So, besides estimating rainfall runoff, proper assessment of snowmelt runoff for efficient management and water resources planning is also required. A Land Surface Model, VIC (Variable Infiltration Capacity) is used at a high resolution grid size of 1 km. Beas river basin up to Thalot in North West Himalayas (NWH) have been selected as the study area. At first model setup is done and VIC has been run in its energy balance mode. The fluxes obtained from VIC has been routed to simulate the discharge for the time period of (2003-2006). Data Assimilation is done for the year 2006 and the techniques of Data Assimilation considered in this study are Direct Insertion (D.I) and Ensemble Kalman Filter (EnKF) that uses observations of snow covered area (SCA) to update hydrologic model states. The meteorological forcings were taken from 0.5 deg. resolution VIC global forcing data from 1979-2006 with daily maximum temperature, minimum temperature from Climate Research unit (CRU), rainfall from daily variability of NCEP and wind speed from NCEP-NCAR analysis as main inputs and Indian Meteorological Department (IMD) data of 0.25 °. NBSSLUP soil map and land use land cover map of ISRO-GBP project for year 2014 were used for generating the soil parameters and vegetation parameters respectively. The threshold temperature i.e. the minimum rain temperature is -0.5°C and maximum snow temperature is about +0.5°C at which VIC can generate snow fluxes. Hydrological simulations were done using both NCEP and IMD based meteorological Forcing datasets, but very few snow fluxes were obtained using IMD data met forcing, whereas NCEP based met forcing has given significantly better snow fluxes throughout the simulation years as the temperature resolution as given by IMD data is 0.5°C and rainfall resolution of 0.25°C. The simulated discharge has been validated using observed data from BBMB (Bhakra Beas Management Board) and coefficient of Correlation(R2) measured for (2003-2006) was 0.67 and 0.61 for the year 2006.But as VIC does not consider snowmelt runoff as a part of the total discharge, snowmelt runoff has been estimated for the simulation both with and without D.A. The snow fluxes as generated from VIC gives basin average estimates of Snow Cover, SWE, Snow Depth and Snow melt. It has been observed to be overestimated when model predicted snow cover is compared with MODIS SCA of 500 m resolution from MOD10A2 for each year. So MODIS 8-day snow cover area has been assimilated directly into the model state as well as by using EnKF after every 8 days for the year 2006.D.I Technique performed well as compared to EnKF. R2 between Model SCA and MODIS SCA is estimated as 0.73 after D.I with Root Mean Square Error (RMSE) of +0.19. After direct Insertion of D.A, SCA has been reduced comparatively which resulted in 7% reduction of annual snowmelt contribution to total discharge.The assimilation of MODIS SCA data hence improved the snow cover area (SCA) fraction and finally updated other snow components.

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16

Wu, C. H., G. R. Huang, and H. J. Yu. "Prediction of extreme floods based on CMIP5 climate models: a case study in the Beijiang River basin, South China." Hydrology and Earth System Sciences Discussions 11, no. 8 (August 13, 2014): 9643–69. http://dx.doi.org/10.5194/hessd-11-9643-2014.

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Abstract. The occurrence of climate warming is unequivocal, and is expected to be experienced through increases in the magnitude and frequency of extreme events, including flooding. This paper presents an analysis of the implications of climate change on the future flood hazard in the Beijiang River basin in South China, using a Variable Infiltration Capacity (VIC) model. Uncertainty is considered by employing five Global Climate Models (GCMs), three emission scenarios (RCP2.6, RCP4.5, and RCP8.5), ten downscaling simulations for each emission scenario, and two stages of future periods (2020–2050, 2050–2080). Credibility of the projected changes in floods is described using an uncertainty expression approach, as recommended by the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). The results suggest that the VIC model shows a good performance in simulating extreme floods, with a daily runoff Nash and Sutcliffe efficiency coefficient (NSE) of 0.91. The GCMs and emission scenarios are a large source of uncertainty in predictions of future floods over the study region, although the overall uncertainty range for changes in historical extreme precipitation and flood magnitudes are well represented by the five GCMs. During the periods 2020–2050 and 2050–2080, annual maximum 1-day discharges (AMX1d) and annual maximum 7-day flood volumes (AMX7fv) are projected to show very similar trends, with the largest possibility of increasing trends occurring under the RCP2.6 scenario, and the smallest possibility of increasing trends under the RCP4.5 scenario. The projected ranges of AMX1d and AMX7fv show relatively large variability under different future scenarios in the five GCMs, but most project an increase during the two future periods (relative to the baseline period 1970–2000).

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Singh, T. P., M. Deshpande, S. Das, and V. Kumbhar. "DROUGHT PATTERN ASSESSMENT OVER MARATHWADA, INDIA THROUGH THE DEVELOPMENT OF MULTIVARIATE ADVANCE DROUGHT RESPONSE INDEX." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2022 (May 31, 2022): 1173–80. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2022-1173-2022.

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Abstract. The intensity and frequency with which recent drought events are occurring has made management of food and water a challenge. The situation in Indian subcontinent is no difference. The presented study takes inspiration from such problems to propose a remote sensing based multivariate advance drought response index (ADRI). The proposed multivariate index takes into consideration long term conditions of precipitation, normalized difference vegetation index (NDVI), brightness temperature and soil moisture in a linear way for 8-day drought assessment over drought affected Marathwada region, Maharashtra, India. A value of 33 corresponding to ADRI was found to be normal condition over two decades which corresponds to normal vegetation condition index (VCI) value of 51.1 and 54.2. The last 7 years shows a consistent pattern in the change of regional ADRI values which suggests the years in which agricultural assistance is needed over the region. Drought over the region is found to shift from central to eastern and northern regions in the last 5 years. Temporal analysis for the duration suggests up to 5 percent of the area of Marathwada has been facing severe drought conditions over the last decade while up to 70 percent of the area is experience below normal conditions with varying intensities of water stress. The districts of Latur, Parbhani, Hingoli and Nanded which are downstream river Godavari have been affected the most due to large percentage of land being under agriculture.

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Wu, C. H., G. R. Huang, and H. J. Yu. "Prediction of extreme floods based on CMIP5 climate models: a case study in the Beijiang River basin, South China." Hydrology and Earth System Sciences 19, no. 3 (March 13, 2015): 1385–99. http://dx.doi.org/10.5194/hess-19-1385-2015.

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Abstract. The occurrence of climate warming is unequivocal, and is expected to be experienced through increases in the magnitude and frequency of extreme events, including flooding. This paper presents an analysis of the implications of climate change on the future flood hazard in the Beijiang River basin in South China, using a variable infiltration capacity (VIC) model. Uncertainty is considered by employing five global climate models (GCMs), three emission scenarios (representative concentration pathway (RCP) 2.6, RCP4.5, and RCP8.5), 10 downscaling simulations for each emission scenario, and two stages of future periods (2020–2050, 2050–2080). Credibility of the projected changes in floods is described using an uncertainty expression approach, as recommended by the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). The results suggest that the VIC model shows a good performance in simulating extreme floods, with a daily runoff Nash–Sutcliffe efficiency coefficient (NSE) of 0.91. The GCMs and emission scenarios are a large source of uncertainty in predictions of future floods over the study region, although the overall uncertainty range for changes in historical extreme precipitation and flood magnitudes are well represented by the five GCMs. During the periods 2020–2050 and 2050–2080, annual maximum 1-day discharges (AMX1d) and annual maximum 7-day flood volumes (AMX7fv) are expected to show very similar trends, with the largest possibility of increasing trends occurring under the RCP2.6 scenario, and the smallest possibility of increasing trends under the RCP4.5 scenario. The projected ranges of AMX1d and AMX7fv show relatively large variability under different future scenarios in the five GCMs, but most project an increase during the two future periods (relative to the baseline period 1970–2000).

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Yang, Xiaoli, Weifei Zheng, Liliang Ren, Mengru Zhang, Yuqian Wang, Yi Liu, Fei Yuan, and Shanhu Jiang. "Potential impact of climate change to the future streamflow of Yellow River Basin based on CMIP5 data." Proceedings of the International Association of Hydrological Sciences 376 (February 1, 2018): 97–104. http://dx.doi.org/10.5194/piahs-376-97-2018.

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Abstract. The Yellow River Basin (YRB) is the largest river basin in northern China, which has suffering water scarcity and drought hazard for many years. Therefore, assessments the potential impacts of climate change on the future streamflow in this basin is very important for local policy and planning on food security. In this study, based on the observations of 101 meteorological stations in YRB, equidistant CDF matching (EDCDFm) statistical downscaling approach was applied to eight climate models under two emissions scenarios (RCP4.5 and RCP8.5) from phase five of the Coupled Model Intercomparison Project (CMIP5). Variable infiltration capacity (VIC) model with 0.25∘ × 0.25∘ spatial resolution was developed based on downscaled fields for simulating streamflow in the future period over YRB. The results show that with the global warming trend, the annual streamflow will reduced about 10 % during the period of 2021–2050, compared to the base period of 1961–1990 in YRB. There should be suitable water resources planning to meet the demands of growing populations and future climate changing in this region.

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Arora, S., A. V. Kulkarni, P. Ghosh, and S. K. Satheesh. "ESTIMATING CONTRIBUTION OF WATER FLOW COMPONENTS TO KAMENG RIVER BASIN USING HYDROLOGICAL MODELLING." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2021 (June 28, 2021): 431–36. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2021-431-2021.

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Abstract. The Himalayas, also known as third pole of the Earth feed some of the major rivers of the world viz. Ganga, Indus, Brahmaputra etc. The accurate assessment of water resources in eastern Himalayas is very important for respective policy makers. The detailed assessment of water resources and hydrological cycle component are very critical for attaining United Nations sustainable development goals (SDGs) such as affordable and clean energy, clean water and sanitation and building resilient infrastructure This study focuses on Kameng river basin, estimating the melt water & its contribution to the total discharge of the river. A 3-layer VIC model coupled with energy balance algorithm is used to estimate the patterns of melt and discharge profile in the region. Net contribution of melt water to the river were estimated to be about 18% during peak melt season in upper catchments. With advancement in technology, acquiring meteorological data via remote sensing has become more accurate & of high resolution. This data is one of the major inputs of the model. With accurate forecasting of these parameters, multipurpose hydropower projects in these regions can plan well in advance thus playing a major role in Integrated Water Resource Management. In current study the coefficient of determination & Nash-Sutcliffe efficiency were calculated to be 0.82 & 0.71 respectively. With increasing population in the region, any substantial change in the streamflow will have consequences unknown as of now, thus making this study a necessity & need of hour.

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Zhu, Chunmei, and Dennis P. Lettenmaier. "Long-Term Climate and Derived Surface Hydrology and Energy Flux Data for Mexico: 1925–2004." Journal of Climate 20, no. 9 (May 1, 2007): 1936–46. http://dx.doi.org/10.1175/jcli4086.1.

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Abstract Studying the role of land surface conditions in the Mexican portion of the North American monsoon system (NAMS) region has been a challenge due to the paucity of long-term observations. A long-term gridded observation-based climate dataset suitable for forcing land surface models, as well as model-derived land surface states and fluxes for a domain consisting of all of Mexico, is described. The datasets span the period of January 1925–October 2004 at 1/8° spatial resolution at a subdaily (3 h) time step. The simulated runoff matches the observations plausibly over most of the 14 small river basins spanning all of Mexico, which suggests that long-term mean evapotranspiration is realistically reproduced. On this basis, and given the physically based model parameterizations of soil moisture and energy fluxes, the other surface fluxes and state variables such as soil moisture should be represented reasonably. In addition, a comparison of the surface fluxes from this study is performed with North American Regional Reanalysis (NARR) data on a seasonal mean basis. The results indicate that downward shortwave radiation is generally smaller than in the NARR data, especially in summer. Net radiation, on the other hand, is somewhat larger in the Variable Infiltration Capacity (VIC) hydrological model than in the NARR data for much of the year over much of the domain. The differences in radiative and turbulent fluxes are attributed to (i) the parameterization used in the VIC forcings for solar and downward longwave radiation, which links them to the daily temperature and temperature range, and (ii) differences in the land surface parameterizations used in VIC and the NCEP–Oregon State University–U.S. Air Force–NWS/Hydrologic Research Lab (Noah) land scheme used in NARR.

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Lu, Wenjun, Weiguang Wang, Quanxi Shao, Zhongbo Yu, Zhenchun Hao, Wanqiu Xing, Bin Yong, and Jinxing Li. "Hydrological projections of future climate change over the source region of Yellow River and Yangtze River in the Tibetan Plateau: A comprehensive assessment by coupling RegCM4 and VIC model." Hydrological Processes 32, no. 13 (May 29, 2018): 2096–117. http://dx.doi.org/10.1002/hyp.13145.

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23

Shah, Harsh L., and Vimal Mishra. "Uncertainty and Bias in Satellite-Based Precipitation Estimates over Indian Subcontinental Basins: Implications for Real-Time Streamflow Simulation and Flood Prediction*." Journal of Hydrometeorology 17, no. 2 (February 1, 2016): 615–36. http://dx.doi.org/10.1175/jhm-d-15-0115.1.

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Abstract Real-time streamflow monitoring is essential over the Indian subcontinental river basins, as a large population is affected by floods. Moreover, streamflow monitoring helps in managing water resources in the agriculture-dominated region. In this study, the authors systematically investigated the bias and uncertainty in satellite-based precipitation products [Climate Prediction Center morphing technique (CMORPH); Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks (PERSIANN); PERSIANN Climate Data Record (PERSIANN-CDR); and Tropical Rainfall Measuring Mission (TRMM), version 7, real-time (3B42RTV7) and gauge-adjusted (3B42V7) products] over the Indian subcontinental river basins for the period of 2000–13. Moreover, the authors evaluated the influence of bias in the satellite precipitation on real-time streamflow monitoring and flood assessment over the Mahanadi river basin. Results showed that CMORPH and PERSIANN underestimated daily mean precipitation over the majority of the subcontinental river basins. On the other hand, TRMM-3B42RTV7 overestimated daily mean precipitation over most of the river basins in the subcontinent. While gauge-adjusted products of PERSIANN (PERSIANN-CDR) and TRMM (TRMM-3B42V7) performed better than their real-time products, large biases remain in their performance to capture extreme precipitation (both frequency and magnitudes) over the subcontinental basins. Among the real-time precipitation products, TRMM-3B42RTV7 performed better than CMORPH and PERSIANN over the majority of the Indian subcontinental basins. Daily streamflow simulations using the Variable Infiltration Capacity model (VIC) for the Mahanadi river basin showed a better performance by the TRMM-3B42RTV7 product than the other real-time datasets. Moreover, daily streamflow simulations over the Mahanadi river basin showed that bias in real-time precipitation products affects the initial condition and precipitation forcing, which in turn affects flood peak timing and magnitudes.

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Liu, Yang Yang, and Bo Juan Liu. "Hydrologic Responses to Climate Change in Mountainous Watershed of Southwest China, 1980 to 2010." Applied Mechanics and Materials 675-677 (October 2014): 794–800. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.794.

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Hydrologic responses to climate change have become a great challenge and attracted widespread attention of the researchers. The mountainous Qingyi River watershed in the southwest, China, had experienced significant climate change in the past three decades. It is necessary to investigate the hydrologic responses to these changes. Therefore, the effect of climate change on evapotranspiration (ET), surface runoff, baseflow and streamflow were assessed using Variable Infiltration Capacity (VIC) hydrologic model. The Mann–Kendall test analysis was first used to identify the long-term change in precipitation and temperature over the period of 1980–2010. It revealed that there is a significant change in annual temperature particularly in February, March, July and September, whereas an insignificant change in annual precipitation was founded. Hydrologic simulations show that hydrologic responses to climate change were varied from region to region. Surface runoff was more sensitive than ET and baseflow. Monthly variation of the hydrologic processes, especially the change in surface runoff, was mainly attributed to seasonal variation in precipitation. The results of this research can be a useful source of information for the decision making in water resources management and protection.

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Liu, Zhaofei, Zongxue Xu, Guobin Fu, and Zhijun Yao. "Assessing the hydrological impacts of climate change in the headwater catchment of the Tarim River basin, China." Hydrology Research 44, no. 5 (October 9, 2012): 834–49. http://dx.doi.org/10.2166/nh.2012.237.

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Two statistical downscaling models were used to downscale regional climate change scenarios, on the basis of the outputs of three general circulation models (GCMs) and three emission scenarios. Driven by these climate change scenarios, a distributed macro-scale hydrological model (the Variable Infiltration Capacity (VIC) model) was applied to assess the impact of climate change on hydrological processes in the headwater catchment (HC) of the Tarim River basin, China. The results showed that the HC tends to experience warmer and drier conditions under the combined climate change scenarios. The predictions show a decreasing trend of the runoff in the HC, driven by the combined climate change scenarios. The results predicted an increasing trend for winter runoff however, which was consistent with the forecasts from most previous studies on other locations such as the region of St Lawrence tributaries (Quebec, Canada) and the Willamette River Basin (Oregon, USA). There was an inconsistent intra-annual distribution of the changes in precipitation and runoff in the HC; these inconsistencies may be explained by increasing snowmelt runoff resulting from higher air temperature. It was concluded that uncertainties within different GCM outputs are more significant than emission scenarios in the assessment of the potential impact of climate change.

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Martínez-Fernández, José, Nilda Sánchez, and Carlos M. Herrero-Jiménez. "Recent trends in rivers with near-natural flow regime." Progress in Physical Geography: Earth and Environment 37, no. 5 (August 7, 2013): 685–700. http://dx.doi.org/10.1177/0309133313496834.

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The main objective of this research was to study the streamflow evolution of a representative sample of the Spanish near-natural-regime fluvial system over the last four decades of the 20th century. The focus of this study was on those headwater river basins that, not having been subject to substantial human alteration directly via the flow regime, might still have been affected by changes in land management. A representative sample of 74 rivers was selected and a statistical analysis was performed to detect seasonal and annual trends, and the magnitude of streamflow change. Almost all of the rivers studied experienced reductions in streamflow, and three quarters of them had negative and significant (p<0.05) trends in streamflow change. It was impossible to detect any spatial pattern in terms of the type or trend magnitude. The main decreases in the discharge of these near-natural rivers in Spain was observed in the spring and summer, when 81% and 70% of the rivers, respectively, exhibited significant negative trends. The magnitudes of the changes are also remarkable. The average annual percentage change in streamflow magnitude of the 74 basins was –1.45% per year, which corresponds to an average streamflow reduction equivalent to 153 hm3 every year. The results of this study are relevant in view of future climatic scenarios and the evolution of land management in rural and mountain areas, as has already been observed in many parts of the Mediterranean and other regions. Global warming, resulting in continuous temperature increases and therefore evapotranspiration increases, is clearly one factor potentially affecting streamflow, together with land abandonment and subsequent continuous forest expansion. These results obtained in Spain could be extrapolated to other areas in the Mediterranean and beyond and should be taken into account in any water policy and water management in the near future.

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Dallmeyer, A., and M. Claussen. "The influence of land cover change in the Asian monsoon region on present-day and mid-Holocene climate." Biogeosciences Discussions 8, no. 1 (February 24, 2011): 1693–731. http://dx.doi.org/10.5194/bgd-8-1693-2011.

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Abstract. Using the general circulation model ECHAM5/JSBACH, we investigate the biogeophysical effect of large-scale afforestation and deforestation in the Asian monsoon domain on present-day and mid-Holocene climate. We demonstrate that the applied land cover change does not only modify the local climate but also change the climate in North Africa and the Middle East via teleconnections. Deforestation in the Asian monsoon domain enhances the rainfall in North Africa. In parts of the Sahara summer precipitation is more than doubled. In contrast, afforestation strongly decreases summer rainfall in the Middle East and even leads to the cessation of the rainfall-activity in some parts of this region. Regarding the local climate, deforestation results in a reduction of precipitation and a cooler climate as grass mostly has a higher albedo than forests. However, in the core region of the Asian monsoon the decrease of evaporative cooling in the monsoon season overcompensates this signal and results in a net warming. Afforestation has mainly the opposite effect, although the pattern of change is less clear. It leads to more precipitation in most parts of the Asian monsoon domain and a warmer climate except for the southern regions where a stronger evaporation decreases near-surface temperatures in the monsoon season. When prescribing mid-Holocene insolation, the pattern of local precipitation change differs. Afforestation particularly increases monsoon rainfall in the region along the Yellow River which was the settlement area of major prehistoric cultures. In this region, the effect of land cover change on precipitation is half as large as the orbitally-induced precipitation change. Thus, our model results reveal that mid- to late-Holocene land cover change could strongly have contributed to the decreasing Asian monsoon precipitation during the Holocene known from reconstructions.

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Dallmeyer, A., and M. Claussen. "The influence of land cover change in the Asian monsoon region on present-day and mid-Holocene climate." Biogeosciences 8, no. 6 (June 10, 2011): 1499–519. http://dx.doi.org/10.5194/bg-8-1499-2011.

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Abstract. Using the general circulation model ECHAM5/JSBACH, we investigate the biogeophysical effect of large-scale afforestation and deforestation in the Asian monsoon domain on present-day and mid-Holocene climate. We demonstrate that the applied land cover change does not only modify the local climate but also change the climate in North Africa and the Middle East via teleconnections. Deforestation in the Asian monsoon domain enhances the rainfall in North Africa. In parts of the Sahara summer precipitation is more than doubled. In contrast, afforestation strongly decreases summer rainfall in the Middle East and even leads to the cessation of the rainfall-activity in some parts of this region. Regarding the local climate, deforestation results in a reduction of precipitation and a cooler climate as grass mostly has a higher albedo than forests. However, in the core region of the Asian monsoon the decrease in evaporative cooling in the monsoon season overcompensates this signal and results in a net warming. Afforestation has mainly the opposite effect, although the pattern of change is less clear. It leads to more precipitation in most parts of the Asian monsoon domain and a warmer climate except for the southern regions where a stronger evaporation decreases near-surface temperatures in the monsoon season. When prescribing mid-Holocene insolation, the pattern of local precipitation change differs. Afforestation particularly increases monsoon rainfall in the region along the Yellow River which was the settlement area of major prehistoric cultures. In this region, the effect of land cover change on precipitation is half as large as the orbitally-induced precipitation change. Thus, our model results reveal that mid- to late-Holocene land cover change could strongly have contributed to the decreasing Asian monsoon precipitation during the Holocene known from reconstructions.

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Pierce, D. W., A. L. Westerling, and J. Oyler. "Future humidity trends over the western United States in the CMIP5 global climate models and variable infiltration capacity hydrological modeling system." Hydrology and Earth System Sciences Discussions 9, no. 12 (December 12, 2012): 13651–91. http://dx.doi.org/10.5194/hessd-9-13651-2012.

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Abstract. Global climate models predict relative humidity (RH) in the western US will decrease at a rate of about 0.1–0.6% per decade, although with seasonal differences (most drying in spring and summer), geographical variability (greater declines in the interior), stronger reductions for greater anthropogenic radiative forcing, and notable spread among the models. Although atmospheric moisture content increases, this is more than compensated for by higher air temperatures, leading to declining RH. Fine-scale hydrological simulations driven by the global model results should reproduce these trends. It is shown that the meteorological algorithms used by the Variable Infiltration Capacity (VIC) hydrological model, when driven by daily Tmin, Tmax, and precipitation (a configuration used in numerous published studies), do not preserve the original global model's humidity trends. Trends are biased positive in the interior western US, so that strong RH decreases are changed to weak decreases, and weak decreases are changed to increases. This happens because the meteorlogical algorithms VIC incorporates infer an overly large positive trend in atmospheric moisture content in this region. The result could downplay the effects of decreasing RH on plants and wildfire. RH trends along the coast have a weak negative bias due to neglect of the ocean's moderating influence. A numerical experiment where VIC's values of Tdew are altered to compensate for the RH error suggests that eliminating the atmospheric moisture bias could, in and of itself, decrease runoff up to 14% in high-altitude regions east of the Sierra Nevada and Cascades, and reduce estimated Colorado River runoff at Lees Ferry up to 4 % by the end of the century.

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30

Zhao, Chongxu, Liliang Ren, Fei Yuan, Limin Zhang, Shanhu Jiang, Jiayong Shi, Tao Chen, et al. "Statistical and Hydrological Evaluations of Multiple Satellite Precipitation Products in the Yellow River Source Region of China." Water 12, no. 11 (November 3, 2020): 3082. http://dx.doi.org/10.3390/w12113082.

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Comprehensively evaluating satellite precipitation products (SPPs) for hydrological simulations on watershed scales is necessary given that the quality of different SPPs varies remarkably in different regions. The Yellow River source region (YRSR) of China was chosen as the study area. Four SPPs were statistically evaluated, namely, the Tropical Rainfall Measurement Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) 3B42V7, Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks Climate Data Record (PERSIANN-CDR), Integrated Multisatellite Retrievals for Global Precipitation Measurement final run (IMERG-F), and gauge-corrected Global Satellite Mapping of Precipitation (GSMaP-Gauge) products. Subsequently, the hydrological utility of these SPPs was assessed via the variable infiltration capacity hydrological model on a daily temporal scale. Results show that the four SPPs generally demonstrate similar spatial distribution pattern of precipitation to that of the ground observations. In the period of January 1998 to December 2016, 3B42V7 outperforms PERSIANN-CDR on basin scale. In the period of April 2014 to December 2016, GSMaP-Gauge demonstrates the highest precipitation monitoring capability and hydrological utility among all SPPs on grid and basin scales. In general, 3B42V7, IMERG-F, and GSMaP-Gauge show a satisfactory hydrological performance in streamflow simulations in YRSR. IMERG-F has an improved hydrological utility than 3B42V7 in YRSR.

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Islam, Siraj Ul, Charles L. Curry, Stephen J. Déry, and Francis W. Zwiers. "Quantifying projected changes in runoff variability and flow regimes of the Fraser River Basin, British Columbia." Hydrology and Earth System Sciences 23, no. 2 (February 13, 2019): 811–28. http://dx.doi.org/10.5194/hess-23-811-2019.

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Abstract. In response to ongoing and future-projected global warming, mid-latitude, nival river basins are expected to transition from a snowmelt-dominated flow regime to a nival–pluvial one with an earlier spring freshet of reduced magnitude. There is, however, a rich variation in responses that depends on factors such as the topographic complexity of the basin and the strength of maritime influences. We illustrate the potential effects of a strong maritime influence by studying future changes in cold season flow variability in the Fraser River Basin (FRB) of British Columbia, a large extratropical watershed extending from the Rocky Mountains to the Pacific Coast. We use a process-based hydrological model driven by an ensemble of 21 statistically downscaled simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5), following the Representative Concentration Pathway 8.5 (RCP 8.5). Warming under RCP 8.5 leads to reduced winter snowfall, shortening the average snow accumulation season by about one-third. Despite this, large increases in cold season rainfall lead to unprecedented cold season peak flows and increased overall runoff variability in the VIC simulations. Increased cold season rainfall is shown to be the dominant climatic driver in the Coast Mountains, contributing 60 % to mean cold season runoff changes in the 2080s. Cold season runoff at the outlet of the basin increases by 70 % by the 2080s, and its interannual variability more than doubles when compared to the 1990s, suggesting substantial challenges for operational flow forecasting in the region. Furthermore, almost half of the basin (45 %) transitions from a snow-dominated runoff regime in the 1990s to a primarily rain-dominated regime in the 2080s, according to a snowmelt pulse detection algorithm. While these projections are consistent with the anticipated transition from a nival to a nival–pluvial hydrologic regime, the marked increase in FRB cold season runoff is likely linked to more frequent landfalling atmospheric rivers in the region projected in the CMIP5 models, providing insights for other maritime-influenced extratropical basins.

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Pierce, D. W., A. L. Westerling, and J. Oyler. "Future humidity trends over the western United States in the CMIP5 global climate models and variable infiltration capacity hydrological modeling system." Hydrology and Earth System Sciences 17, no. 5 (May 14, 2013): 1833–50. http://dx.doi.org/10.5194/hess-17-1833-2013.

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Abstract. Global climate models predict relative humidity (RH) in the western US will decrease at a rate of about 0.1–0.6 percentage points per decade, albeit with seasonal differences (most drying in spring and summer), geographical variability (greater declines in the interior), stronger reductions for greater anthropogenic radiative forcing, and notable spread among the models. Although atmospheric moisture content increases, this is more than compensated for by higher air temperatures, leading to declining RH. Fine-scale hydrological simulations driven by the global model results should reproduce these trends. It is shown that the MT-CLIM meteorological algorithms used by the Variable Infiltration Capacity (VIC) hydrological model, when driven by daily Tmin, Tmax, and precipitation (a configuration used in numerous published studies), do not preserve the original global model's humidity trends. Trends are biased positive in the interior western US, so that strong RH decreases are changed to weak decreases, and weak decreases are changed to increases. This happens because the MT-CLIM algorithms VIC incorporates infer an overly large positive trend in atmospheric moisture content in this region, likely due to an underestimate of the effect of increasing aridity on RH. The result could downplay the effects of decreasing RH on plants and wildfire. RH trends along the coast have a weak negative bias due to neglect of the ocean's moderating influence. A numerical experiment where the values of Tdew are altered to compensate for the RH error suggests that eliminating the atmospheric moisture bias could, in and of itself, decrease runoff up to 14% in high-altitude regions east of the Sierra Nevada and Cascades, and reduce estimated Colorado River runoff at Lees Ferry up to 4% by the end of the century. It could also increase the probability of large fires in the northern and central US Rocky Mountains by 13 to 60%.

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Tan, Linshan, Kaiyuan Zheng, Qiangqiang Zhao, and Yanjuan Wu. "Evapotranspiration Estimation Using Remote Sensing Technology Based on a SEBAL Model in the Upper Reaches of the Huaihe River Basin." Atmosphere 12, no. 12 (November 30, 2021): 1599. http://dx.doi.org/10.3390/atmos12121599.

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Understanding the spatial and temporal variations of evapotranspiration (ET) is vital for water resources planning and management and drought monitoring. The development of a satellite remote sensing technique is described to provide insight into the estimation of ET at a regional scale. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to calculate the actual ET on a daily scale from Landsat-8 data and daily ground-based meteorological data in the upper reaches of Huaihe River on 20 November 2013, 16 April 2015 and 23 March 2018. In order to evaluate the performance of the SEBAL model, the daily SEBAL ET (ETSEBAL) was compared against the daily reference ET (ET0) from four theoretical methods: the Penman-Monteith (P-M), Irmak-Allen (I-A), the Turc, and Jensen-Haise (J-H) method, the ETMOD16 product from the MODerate Resolution Imaging Spectrometer (MOD16) and the ETVIC from Variable Infiltration Capacity Model (VIC). A linear regression equation and statistical indices were used to model performance evaluation. The results showed that the daily ETSEBAL correlated very well with the ET0, ETMOD16, and ETVIC, and bias between the ETSEBAL with them was less than 1.5%. In general, the SEBAL model could provide good estimations in daily ET over the study region. In addition, the spatial-temporal distribution of ETSEBAL was explored. The variation of ETSEBAL was significant in seasons with high values during the growth period of vegetation in March and April and low values in November. Spatially, the daily ETSEBAL values in the mountain area were much higher than those in the plain areas over the study region. The variability of ETSEBAL in this study area was positively correlated with elevation and negatively correlated with surface reflectance, which implies that elevation and surface reflectance are the important factors for predicting ET in this study area.

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Dibike, Yonas, Hyung-Il Eum, Paulin Coulibaly, and Joshua Hartmann. "Projected Changes in the Frequency of Peak Flows along the Athabasca River: Sensitivity of Results to Statistical Methods of Analysis." Climate 7, no. 7 (July 4, 2019): 88. http://dx.doi.org/10.3390/cli7070088.

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Flows originating from alpine dominated cold region watersheds typically experience extended winter low flows followed by spring snowmelt and summer rainfall driven high flows. In a warmer climate, there will be a temperature-induced shift in precipitation from snowfall towards rain along with changes in precipitation intensity and snowmelt timing, resulting in alterations in the frequency and magnitude of peak flow events. This study examines the potential future changes in the frequency and severity of peak flow events in the Athabasca River watershed in Alberta, Canada. The analysis is based on simulated flow data by the variable infiltration capacity (VIC) hydrologic model driven by statistically downscaled climate change scenarios from the latest coupled model inter-comparison project (CMIP5). The hydrological model projections show an overall increase in mean annual streamflow in the watershed and a corresponding shift in the freshet timing to an earlier period. The river flow is projected to experience increases during the winter and spring seasons and decreases during the summer and early fall seasons, with an overall projected increase in peak flow, especially for low frequency events. Both stationary and non-stationary methods of peak flow analysis, performed at multiple points along the Athabasca River, show that projected changes in the 100-year peak flow event for the high emissions scenario by the 2080s range between 4% and 33% depending on the driving climate models and the statistical method of analysis. A closer examination of the results also reveals that the sensitivity of projected changes in peak flows to the statistical method of frequency analysis is relatively small compared to that resulting from inter-climate model variability.

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Xu, ZhiQing, Ke Fan, and HuiJun Wang. "Decadal Variation of Summer Precipitation over China and Associated Atmospheric Circulation after the Late 1990s." Journal of Climate 28, no. 10 (May 12, 2015): 4086–106. http://dx.doi.org/10.1175/jcli-d-14-00464.1.

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Abstract In this study, the authors found that the summer precipitation over China experienced different decadal variation features from north to south after the late 1990s. In northeastern and North China and the lower–middle reaches of the Yangtze River, precipitation decreased after 1999, while precipitation experienced a significant reduction over South and southwestern China and a significant increase over the southern parts of Hetao region and Huaihe River valley after 2003. The authors next analyzed the associated decadal variation of the atmospheric circulation and attempted to identify the mechanisms causing the two decadal variations of precipitation. The wind anomalies for the former exhibit a barotropic meridional dipole pattern, with anticyclonic anomalies over Mongolia to northern China and cyclonic anomalies over the southeastern Chinese coast to the northwestern Pacific. For the latter, there is a southeast–northwest-oriented dipole pattern in the middle and lower troposphere, with cyclonic anomalies over the northern parts of the Tibetan Plateau and anticyclonic anomalies over the lower–middle reaches of the Yangtze River to southern Japan. An anomalous anticyclone dominates the upper troposphere over China south of 40°N. The authors further found that the summer sea surface temperature (SST) warming over the tropical Atlantic played an important role in the decadal variation around 2003 via inducing teleconnections over Eurasia. In contrast, the decadal variation around 1999 may be caused by the phase shift of the Pacific decadal oscillation (PDO), as has previously been indicated.

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Chen, Lei, Jianxia Chang, Yimin Wang, and Yuelu Zhu. "Assessing runoff sensitivities to precipitation and temperature changes under global climate-change scenarios." Hydrology Research 50, no. 1 (July 5, 2018): 24–42. http://dx.doi.org/10.2166/nh.2018.192.

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Abstract An accurate grasp of the influence of precipitation and temperature changes on the variation in both the magnitude and temporal patterns of runoff is crucial to the prevention of floods and droughts. However, there is a general lack of understanding of the ways in which runoff sensitivities to precipitation and temperature changes are associated with the CMIP5 scenarios. This paper investigates the hydrological response to future climate change under CMIP5 RCP scenarios by using the Variable Infiltration Capacity (VIC) model and then quantitatively assesses runoff sensitivities to precipitation and temperature changes under different scenarios by using a set of simulations with the control variable method. The source region of the Yellow River (SRYR) is an ideal area to study this problem. The results demonstrated that the precipitation effect was the dominant element influencing runoff change (the degree of influence approaching 23%), followed by maximum temperature (approaching 12%). The weakest element was minimum temperature (approaching 3%), despite the fact that the increases in minimum temperature were higher than the increases in maximum temperature. The results also indicated that the degree of runoff sensitivity to precipitation and temperature changes was subject to changing external climatic conditions.

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Pokrovsky, Oleg S., Rinat M. Manasypov, Sergey V. Loiko, Ivan A. Krickov, Sergey G. Kopysov, Larisa G. Kolesnichenko, Sergey N. Vorobyev, and Sergey N. Kirpotin. "Trace element transport in western Siberian rivers across a permafrost gradient." Biogeosciences 13, no. 6 (March 30, 2016): 1877–900. http://dx.doi.org/10.5194/bg-13-1877-2016.

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Abstract. Towards a better understanding of trace element (TE) transport in permafrost-affected Earth surface environments, we sampled ∼ 60 large and small rivers (< 100 to ≤ 150 000 km2 watershed area) of the Western Siberian Lowland (WSL) during spring flood and summer and winter baseflow across a 1500 km latitudinal gradient covering continuous, discontinuous, sporadic and permafrost-free zones. Analysis of ∼ 40 major and TEs in the dissolved (< 0.45 µm) fraction allowed establishing main environmental factors controlling the transport of metals and TEs in rivers of this environmentally important region. No statistically significant effect of the basin size on most TE concentrations was evidenced. Two groups of elements were distinguished: (1) elements that show the same trend throughout the year and (2) elements that show seasonal differences. The first group included elements decreasing northward during all seasons (Sr, Mo, U, As, Sb) marking the underground water influence of river feeding. The elements of the second group exhibited variable behavior in the course of the year. A northward increase during spring period was mostly pronounced for Fe, Al, Co, Zn and Ba and may stem from a combination of enhanced leaching from the topsoil and vegetation and bottom waters of the lakes (spring overturn). A springtime northward decrease was observed for Ni, Cu, Zr and Rb. The increase in element concentration northward was observed for Ti, Ga, Zr and Th only in winter, whereas Fe, Al, rare earth elements (REEs), Pb, Zr, and Hf increased northward in both spring and winter, which could be linked to leaching from peat and transport in the form of Fe-rich colloids. A southward increase in summer was strongly visible for Fe, Ni, Ba, Rb and V, probably due to peat/moss release (Ni, Ba, Rb) or groundwater feeding (Fe, V). Finally, B, Li, Cr, V, Mn, Zn, Cd, and Cs did not show any distinct trend from S to N. The order of landscape component impact on TE concentration in rivers was lakes > bogs > forest. The lakes decreased export of Mn and Co in summer and Ni, Cu, and Rb in spring, presumably due to biotic processes. The lakes enriched the rivers in insoluble lithogenic elements in summer and winter, likely due to TE mobilization from unfrozen mineral sediments. The rank of environmental factors on TE concentration in western Siberian rivers was latitude (three permafrost zones) > season > watershed size. The effect of the latitude was minimal in spring for most TEs but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding versus bog water feeding determined the pattern of TE concentration and fluxes in rivers of various sizes as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most TEs; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. Climate change in western Siberia and permafrost boundary migration will essentially affect the elements controlled by underground water feeding (DIC, alkaline earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plant–peat–mineral soil–river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen with merely active layer thickening and permafrost boundary shift.

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Pokrovsky, O. S., R. M. Manasypov, S. Loiko, I. A. Krickov, S. G. Kopysov, L. G. Kolesnichenko, S. N. Vorobyev, and S. N. Kirpotin. "Trace elements transport in western Siberia rivers across a permafrost gradient." Biogeosciences Discussions 12, no. 21 (November 10, 2015): 17857–912. http://dx.doi.org/10.5194/bgd-12-17857-2015.

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Abstract. Towards a better understanding of trace element transport in permafrost-affected Earth surface environments, we sampled ∼ 60 large and small rivers (< 100 to ≤ 150 000 km2 watershed area) of Western Siberia Lowland (WSL) during spring flood and summer and winter base-flow across a 1500 km latitudinal gradient covering continuous, discontinuous, sporadic and permafrost-free zones. Analysis of ∼ 40 major and trace elements in dissolved (< 0.45 μm) fraction allowed establishing main environmental factors controlling the transport of metals and trace elements in rivers of this environmentally important region. No statistically significant effect of the basin size on most TE concentration was evidenced. Three category of trace elements were distinguished according to their concentration – latitude pattern: (i) increasing northward in spring and winter (Fe, Al, Ga (only winter), Ti (only winter), REEs, Pb, Zr, Hf, Th (only winter)), linked to leaching from peat and/or redox processes and transport in the form of Fe-rich colloids, (ii) decreasing northward during all seasons (Sr, Mo, U, As, Sb) marking the underground water influence of river feeding and (iii) elements without distinct trend from S to N whose variations within each latitude range were higher than the difference between latitudinal ranges (B, Li, Ti (except summer), Cr, V, Mn, Zn, Cd, Cs, Hf, Th). In addition to these general features, specific, northward increase during spring period was mostly pronounced for Fe, Mn, Co, Zn and Ba and may stem from a combination of enhanced leaching from the topsoil and vegetation and bottom waters of the lakes (spring overturn). A spring time northward decrease was observed for Ni, Cu, Zr, Rb. The southward increase in summer was strongly visible for Fe, Ni, Ba, Rb and V, probably due to peat/moss release (Ni, Ba, Rb) or groundwater feeding (Fe, V). The Principal Component Analysis demonstrated two main factors potentially controlling the ensemble of TE concentration variation. The first factor, responsible for 16–20 % of overall variation, included trivalent and tetravalent hydrolysates, Cr, V, and DOC and presumably reflected the presence of organo-mineral colloids, as also confirmed by previous studies in Siberian rivers. The 2nd factor (8–14 % variation) was linked to the latitude of the watershed and acted on elements affected by the groundwater feeding (DIC, Sr, Mo, As, Sb, U), whose concentration decreased significantly northward during all seasons. Overall, the rank of environmental factors on TE concentration in western Siberian rivers was latitude (3 permafrost zones) > season > watershed size. The effect of the latitude was minimal in spring for most TE but highly visible for Sr, Mo, Sb and U. The main factors controlling the shift of river feeding from surface and subsurface flow to deep underground flow in the permafrost-bearing zone were the depth of the active (unfrozen) seasonal layer and its position in organic or mineral horizons of the soil profile. In the permafrost-free zone, the relative role of carbonate mineral-bearing base rock feeding vs. bog water feeding determined the pattern of trace element concentration and fluxes in rivers of various size as a function of season. Comparison of obtained TE fluxes in WSL rivers with those of other subarctic rivers demonstrated reasonable agreement for most trace elements; the lithology of base rocks was the major factor controlling the magnitude of TE fluxes. The climate change in western Siberia and permafrost boundary migration will affect essentially the elements controlled by underground water feeding (DIC, alkaline-earth elements (Ca, Sr), oxyanions (Mo, Sb, As) and U). The thickening of the active layer may increase the export of trivalent and tetravalent hydrolysates in the form of organo-ferric colloids. Plant litter-originated divalent metals present as organic complexes may be retained via adsorption on mineral horizon. However, due to various counterbalanced processes controlling element source and sinks in plants – peat – mineral soil – river systems, the overall impact of the permafrost thaw on TE export from the land to the ocean may be smaller than that foreseen by merely active layer thickening and permafrost boundary shift.

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Xie, Hanyou, Chong Huang, Jing Li, Yitao Zhang, Xiangbo Xu, Deyao Liu, and Zhu Ouyang. "Strong Precipitation and Human Activity Spur Rapid Nitrate Deposition in Estuarine Delta: Multi-Isotope and Auxiliary Data Evidence." International Journal of Environmental Research and Public Health 18, no. 12 (June 8, 2021): 6221. http://dx.doi.org/10.3390/ijerph18126221.

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The intensive development of the Yellow River Delta has caused huge transportation of non-point pollutants into the Bohai Sea through source river estuaries and thus poses a considerable threat to eco-environmental security in the region. Long-term irrigation in the Yellow River basin, with occasional heavy rainfall and the related effects of ensuring hydrological processes and human activities in terms of nitrate N transport via surface water systems, is unclear. Using stable isotope (δ2H-H2O and δ18O-H2O, δ15N-NO3− and δ18O-NO3−) and auxiliary geographic data, the ISO source model was run to quantitatively analyze the supply relationship of river systems and the rapid change in the spatial pattern of nitrate N due to heavy rainfall in the estuarine delta. This analysis made clear the dominant contribution of agricultural activities and urbanization to NO3−-N emission, on which basis refined management measures were proposed to deal with NO3− in surface water from the “source-process”. The results of the study show that: (1) The relationship of surface water replenishment in the Yellow River Delta was affected not only by rainfall, irrigation, and other water conservancy measures but also the proportion of water from Yellow River flow declined from the source to estuary; (2) To a certain extent, rainfall diluted the concentration of nitrate N in the river and increased instantaneous flux of nitrate N into the sea, where nitrate N flux continuously increased from upstream to downstream; (3) The rapid deposition of nitrate in the estuary delta was driven by heavy rainfall and human activities such as excessive use of nitrogen fertilizers, rapid urbanization, and livestock waste discharge, and; (4) Scientific measures were needed to realize the interactive effect of the output of non-point source pollutants and the carrying and absorption capacity of coastal fragile ecosystems of the exogenous inputs.

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Chawla, I., and P. P. Mujumdar. "Isolating the impacts of land use and climate change on streamflow." Hydrology and Earth System Sciences 19, no. 8 (August 24, 2015): 3633–51. http://dx.doi.org/10.5194/hess-19-3633-2015.

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Abstract. Quantifying the isolated and integrated impacts of land use (LU) and climate change on streamflow is challenging as well as crucial to optimally manage water resources in river basins. This paper presents a simple hydrologic modeling-based approach to segregate the impacts of land use and climate change on the streamflow of a river basin. The upper Ganga basin (UGB) in India is selected as the case study to carry out the analysis. Streamflow in the river basin is modeled using a calibrated variable infiltration capacity (VIC) hydrologic model. The approach involves development of three scenarios to understand the influence of land use and climate on streamflow. The first scenario assesses the sensitivity of streamflow to land use changes under invariant climate. The second scenario determines the change in streamflow due to change in climate assuming constant land use. The third scenario estimates the combined effect of changing land use and climate over the streamflow of the basin. Based on the results obtained from the three scenarios, quantification of isolated impacts of land use and climate change on streamflow is addressed. Future projections of climate are obtained from dynamically downscaled simulations of six general circulation models (GCMs) available from the Coordinated Regional Downscaling Experiment (CORDEX) project. Uncertainties associated with the GCMs and emission scenarios are quantified in the analysis. Results for the case study indicate that streamflow is highly sensitive to change in urban areas and moderately sensitive to change in cropland areas. However, variations in streamflow generally reproduce the variations in precipitation. The combined effect of land use and climate on streamflow is observed to be more pronounced compared to their individual impacts in the basin. It is observed from the isolated effects of land use and climate change that climate has a more dominant impact on streamflow in the region. The approach proposed in this paper is applicable to any river basin to isolate the impacts of land use change and climate change on the streamflow.

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Xiao, Mu, Bart Nijssen, and Dennis P. Lettenmaier. "Drought in the Pacific Northwest, 1920–2013." Journal of Hydrometeorology 17, no. 9 (September 1, 2016): 2391–404. http://dx.doi.org/10.1175/jhm-d-15-0142.1.

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Abstract The severity–area–duration (SAD) method is used in conjunction with the Variable Infiltration Capacity model (VIC) to identify the major historical total moisture (TM; soil moisture plus snow water equivalent) droughts over the Pacific Northwest region, defined as the Columbia River basin and the region’s coastal drainages, for the period 1920–2013. The motivation is to understand how droughts identified using TM (a measure similar to that used in the U.S. Drought Monitor) relate to sector-specific drought measures that are more relevant to users. It is found that most of the SAD space is dominated by an extended drought period during the 1930s, although the most severe shorter droughts are in the 1970s (1976–78) and early 2000s (2000–04). The impact of the three severe TM droughts that dominate most of the SAD space are explored in terms of sector-specific measures relevant to dryland and irrigated agriculture, hydropower generation, municipal water supply, and recreation. It is found that in many cases the most severe droughts identified using the SAD method also appear among the most severe sector-specific droughts; however, there are important exceptions. Two types of inconsistencies are examined and the nature of the conditions that give rise to them are explored.

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БАШИРОВ, М. С. Э., and Э. Х. ХАСМАГОМАДОВ. "TOWARDS THE HISTORY AND POPULATION COMPOSITION OF THE HISTORICAL AND GEOGRAPHICAL REGIONS GUMBET, ANDI AND ALATAVIA." Известия СОИГСИ, no. 39(78) (March 31, 2021): 22–33. http://dx.doi.org/10.46698/vnc.2021.78.39.013.

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В публикуемой статье рассматривается вопрос взаимного проникновения и исторических контактов населения приграничных областей Чечни и Дагестана – Гумбета, Анди и Салатавии. В исследовании приводится ряд документальных, нарративных (рукописи) и этнографических источников, позволяющих более тщательно взглянуть на вопрос этногенеза обществ указанных историко-географических областей. Кроме того, выявляется закономерность, согласно которой в пространстве между реками Аргун и Кара-Койсу (приток Сулака) распространен целый ряд топонимов и общин, чьи названия обнаруживают основу гун / хун / хон, что, как это видно из источников, увязывается с кавказскими гуннами, или хонами. Также в контексте затронутой проблематики указывается на движение этнических масс с запада (Нашха, Шубут и т.д.) и юга (Ичкерия) в область Анди и далее – в Салатавию через область Гумбет. Проводится попытка определить время возникновения аула Анди, а также выявить общества и личности, принявшие участие в основании села и выступившие в качестве этнического субстрата, по крайней мере, северной группы андийских поселений и тохумов. Отмечается роль Унсура (Энсура), его братьев Баши и Араша, а также владетелей Ануша и Харчи-хана, принявших первого в андийской котловине после его исхода «из селения Шубут» вследствие произошедшего кровопролития. На основании разностороннего анализа, с привлечением архивных материалов авторами указывается на участие общин Дишний, Гуной, Вашандарой, Харачой, Беной, Зумсой и др. в качестве субстрата при формировании североандийских поселений, а также их частичной миграции в Салатавию. The published article examines the issue of mutual penetration and historical contacts of the population of the border regions of Chechnya and Dagestan - Gumbet, Andi and Salatavia. The study provides a number of documentary, narrative (manuscripts) and ethnographic sources that allow a more thorough look at the issue of the ethnogenesis of societies in these historical and geographical areas. In addition, a pattern is revealed according to which a number of toponyms and communities are widespread in the space between the Argun and Kara-Koisu rivers (a tributary of the Sulak), whose names reveal the basis of the Gun / Hun / Khon, which, as can be seen from the sources, is associated with the Caucasian Huns , or hons. Also, in the context of the problems touched upon, the movement of ethnic masses from the west (Nashkha, Shubut, etc.) and south (Ichkeria) to the Andi region and further to Salatavia through the Gumbet region is indicated. An attempt is made to determine the time of the emergence of the Andi aul, as well as to identify the societies and individuals who took part in the founding of the village and acted as an ethnic substratum, at least, of the northern group of Andean settlements and Tohums. The role of Unsur (Ensur), his brothers Bashi and Arash, as well as the rulers of Anush and Kharchi-khan, who took the first in the Andean basin after his exodus “from the village of Shubut” due to the bloodshed, is noted. Based on a multifaceted analysis, with the involvement of archival materials, the authors point out the participation of the communities of Dishny, Guna, Washandara, Kharacha, Benoy, Zumsoy, etc. as a substrate in the formation of North Indian settlements, as well as their partial migration to Salatavia.

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Liu, M., K. Rajagopalan, S. H. Chung, X. Jiang, J. Harrison, T. Nergui, A. Guenther, et al. "What is the importance of climate model bias when projecting the impacts of climate change on land surface processes?" Biogeosciences Discussions 10, no. 11 (November 4, 2013): 17145–92. http://dx.doi.org/10.5194/bgd-10-17145-2013.

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Abstract. Regional climate change impact (CCI) studies have widely involved downscaling and bias-correcting (BC) Global Climate Model (GCM)-projected climate for driving land surface models. However, BC may cause uncertainties in projecting hydrologic and biogeochemical responses to future climate due to the impaired spatiotemporal covariance of climate variables and a breakdown of physical conservation principles. Here we quantify the impact of BC on simulated climate-driven changes in water variables (evapotranspiration, ET; runoff; snow water equivalent, SWE; and water demand for irrigation), crop yield, biogenic volatile organic compounds (BVOC), nitric oxide (NO) emissions, and dissolved inorganic nitrogen (DIN) export over the Pacific Northwest (PNW) Region. We also quantify the impacts on net primary production (NPP) over a small watershed in the region (HJ Andrews). Simulation results from the coupled ECHAM5/MPI-OM model with A1B emission scenario were firstly dynamically downscaled to 12 km resolutions with WRF model. Then a quantile mapping based statistical downscaling model was used to downscale them into 1/16th degree resolution daily climate data over historical and future periods. Two series climate data were generated according to the option of bias-correction (i.e. with bias-correction (BC) and without bias-correction, NBC). Impact models were then applied to estimate hydrologic and biogeochemical responses to both BC and NBC meteorological datasets. These impact models include a macro-scale hydrologic model (VIC), a coupled cropping system model (VIC-CropSyst), an ecohydrologic model (RHESSys), a biogenic emissions model (MEGAN), and a nutrient export model (Global-NEWS). Results demonstrate that the BC and NBC climate data provide consistent estimates of the climate-driven changes in water fluxes (ET, runoff, and water demand), VOCs (isoprene and monoterpenes) and NO emissions, mean crop yield, and river DIN export over the PNW domain. However, significant differences rise from projected SWE, crop yield from dry lands, and HJ Andrews's ET between BC and NBC data. Even though BC post-processing has no significant impacts on most of the studied variables when taking PNW as a whole, their effects have large spatial variations and some local areas are substantially influenced. In addition, there are months during which BC and NBC post-processing produces significant differences in projected changes, such as summer runoff. Factor-controlled simulations indicate that BC post-processing of precipitation and temperature both substantially contribute to these differences at region scales. We conclude that there are trade-offs between using BC climate data for offline CCI studies vs. direct modeled climate data. These trade-offs should be considered when designing integrated modeling frameworks for specific applications; e.g., BC may be more important when considering impacts on reservoir operations in mountainous watersheds than when investigating impacts on biogenic emissions and air quality (where VOCs are a primary indicator).

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Horan, Robyn, R. Gowri, Pawan S. Wable, Helen Baron, Virginie D. J. Keller, Kaushal K. Garg, Pradeep P. Mujumdar, Helen Houghton-Carr, and Gwyn Rees. "A Comparative Assessment of Hydrological Models in the Upper Cauvery Catchment." Water 13, no. 2 (January 11, 2021): 151. http://dx.doi.org/10.3390/w13020151.

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This paper presents a comparison of the predictive capability of three hydrological models, and a mean ensemble of these models, in a heavily influenced catchment in Peninsular India: GWAVA (Global Water AVailability Assessment) model, SWAT (Soil Water Assessment Tool) and VIC (Variable Infiltration Capacity) model. The performance of the three models and their ensemble were investigated in five sub-catchments in the upstream reaches of the Cauvery river catchment. Model performances for monthly streamflow simulations from 1983–2005 were analysed using Nash-Sutcliffe efficiency, Kling-Gupta efficiency and percent bias. The predictive capability for each model was compared, and the ability to accurately represent key catchment hydrological processes is discussed. This highlighted the importance of an accurate spatial representation of precipitation for input into hydrological models, and that comprehensive reservoir functionality is paramount to obtaining good results in this region. The performance of the mean ensemble was analysed to determine whether the application of a multi-model ensemble approach can be useful in overcoming the uncertainties associated with individual models. It was demonstrated that the ensemble mean has a better predictive ability in catchments with reservoirs than the individual models, with Nash-Sutcliffe values between 0.49 and 0.92. Therefore, utilising multiple models could be a suitable methodology to offset uncertainty in input data and poor reservoir operation functionality within individual models.

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Horan, Robyn, R. Gowri, Pawan S. Wable, Helen Baron, Virginie D. J. Keller, Kaushal K. Garg, Pradeep P. Mujumdar, Helen Houghton-Carr, and Gwyn Rees. "A Comparative Assessment of Hydrological Models in the Upper Cauvery Catchment." Water 13, no. 2 (January 11, 2021): 151. http://dx.doi.org/10.3390/w13020151.

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This paper presents a comparison of the predictive capability of three hydrological models, and a mean ensemble of these models, in a heavily influenced catchment in Peninsular India: GWAVA (Global Water AVailability Assessment) model, SWAT (Soil Water Assessment Tool) and VIC (Variable Infiltration Capacity) model. The performance of the three models and their ensemble were investigated in five sub-catchments in the upstream reaches of the Cauvery river catchment. Model performances for monthly streamflow simulations from 1983–2005 were analysed using Nash-Sutcliffe efficiency, Kling-Gupta efficiency and percent bias. The predictive capability for each model was compared, and the ability to accurately represent key catchment hydrological processes is discussed. This highlighted the importance of an accurate spatial representation of precipitation for input into hydrological models, and that comprehensive reservoir functionality is paramount to obtaining good results in this region. The performance of the mean ensemble was analysed to determine whether the application of a multi-model ensemble approach can be useful in overcoming the uncertainties associated with individual models. It was demonstrated that the ensemble mean has a better predictive ability in catchments with reservoirs than the individual models, with Nash-Sutcliffe values between 0.49 and 0.92. Therefore, utilising multiple models could be a suitable methodology to offset uncertainty in input data and poor reservoir operation functionality within individual models.

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46

OH, DAEYANG. "Changes in Bronze Age Culture Before the Emergence of Lute-shaped Bronze Swords - Focusing on Weiyingzi Culture in Liaoxi area." Yeongnam Archaeological Society, no. 83 (January 30, 2019): 127–67. http://dx.doi.org/10.47417/yar.2019.83.127.

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Weiyingzi Culture was early Bronze Age culture developed around Dalinghe and Xiaolinghe River in the west of Yoha. The period was approximately between 1300 - 1000 B.C and the culture was characterized by dominance of Material Culture of the Steppe region, relics including Zhongyuan-style bronze ritual ware, tomb system using wooden coffins, and so on. The typical type of the Culture was earthen cookware with three legs which was represented by flower-pattern decoration along the mouth (huabiankouyanli, 花邊口沿鬲 ), patternless blown belly (tongfuli, 筒腹鬲 ), and combined form of flat-bottom and patternless rice bowel (bo, 鉢). This study attempted a preliminary study for reinvestigation on the characteristics and formation process of Weiyingzi Culture by removing differences in recognition and errors in previous studies on such themes and finding out inherent characteristics and external factors of the Culture. In conclusion, one of the reasons for the formation of Weiyingzi Culture in around 1300 B.C. was introduction of Material Culture of the Steppe region, which was also found in the surrounding areas such as Hebei, southeast of Inner Mongolia, and Fuxin. In consideration of the distribution status and characteristics of buried ritual bronzeware in Zhongyuan and that the Material Culture of the Steppe was widely found in Shanxi and north region of Shanxi along the migration route of the Steppe tribe, it was assumed that the migration route of the Weiyingzi Culture was via Ordos Plateau, passing through Liaoxi Zoulang region in the northeast of Hebei. Weiyingzi Culture is suspected to have brought by those who contacted Zhongyuan Culture. Meanwhile, it was noted that Weiyingzi Culture has a few significant factors inherent in Gaotaishan. Since Gaotaishan culture had also strong characteristics of Steppe Culture, it was suspected that the people who remained in that area could accept Steppe Culture easily. As for the surrounding areas, community group who had strong color of Upper Zhangjiayuan Culture advanced to the borderline region with Hebei. Xiquegou-decendant community group who had more connected with Lower Xiajiadian Culture advanced to the borderline regions with southeast of Inner Mongolia and Liaoxi. In the borderline regions with Liaoxi and Liadong, community group of Gaotaishan culture lived there. People in those areas accepted Material Culture of the Steppe region which started to get in from the west without much resistance while the Lower Xiajiadian Culture that had dominated these areas for about 500 years still remained. In that aspect, there was high possibility of significant level of affinity and cultural exchange, although the background cultures were different to each other. It was found that part of natives who remained in Liaoxi area after being subjected to Lower Xiajiadian Culture had blood ties and cultural connections with Gaotaishan culture in the East. Based on that, it was assumed that they selectively accepted Material Culture of the Steppe region flown into that area via Zhongyuan and Hebei and contributed to the formation of Weiyingzi Culture.

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Zhao, Yanqiong, Jinhua Cheng, Yongguang Zhu, and Yanpu Zhao. "Spatiotemporal Evolution and Regional Differences in the Production-Living-Ecological Space of the Urban Agglomeration in the Middle Reaches of the Yangtze River." International Journal of Environmental Research and Public Health 18, no. 23 (November 27, 2021): 12497. http://dx.doi.org/10.3390/ijerph182312497.

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The urban agglomeration in the middle reaches of the Yangtze River, which is the second largest urban agglomeration in China, represents a typical land space range of ecological vulnerability in China. Large differences occur in economic development mode between resource- and non-resource-based cities in this basin area. Accurate identification of the evolution and regional differences in the production-living-ecological space (PLES) is very important in order to elucidate the development and utilization of land space in the region. At present, relevant research has largely focused on the classification and determination of PLES temporal and spatial patterns. Temporal and spatial pattern research has mainly considered a single scale of administrative division, whereas fewer studies have analyzed the temporal and spatial patterns and regional differences in the PLES in ecologically fragile natural watersheds. Therefore, based on PLES classification, the regional differences in the PLES between two types of cities in the basin are measured via the Theil index and exploratory spatial data analysis (ESDA). First, the ecological space (ES) of these two types of cities in the urban agglomeration in the middle reaches of the Yangtze River is compressed by the production space (PS) and living space (LS), in which the ES of resource-based cities is compressed for a longer period, and the phenomenon involving PS compression by the LS and ES mainly occurs in non-resource-based cities within the urban agglomeration in the middle reaches of the Yangtze River. Second, the PLES of these two types of cities exhibits the characteristics of spatial aggregation, and high- and low-density areas of the PLES remain relatively stable. Third, the regional differences in the PLES of the urban agglomeration in the middle reaches of the Yangtze River mainly originate from intraregional differences. The PLES of these two types of cities in the urban agglomeration in the middle reaches of the Yangtze River is more sensitive to changes in economic development than to those in the population distribution.

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Wang, Haoran, Mengdi Zhang, Chuanying Wang, Kaiyue Wang, Chen Wang, Yang Li, Xiuling Bai, and Yunkai Zhou. "Spatial and Temporal Changes of Landscape Patterns and Their Effects on Ecosystem Services in the Huaihe River Basin, China." Land 11, no. 4 (April 1, 2022): 513. http://dx.doi.org/10.3390/land11040513.

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Landscape pattern changes caused by human activities are among the most important driving factors affecting ecosystem spatial structure and components, and significantly impact ecosystem services. Understanding the relationship between landscape patterns and ecosystem services is important for improving regional conservation and establishing ecosystem management strategies. Taking the Huaihe River Basin as an example, this study used land-use data, meteorological data, and topographic data to analyze the spatial and temporal changes in landscape patterns via landscape transfer matrix and landscape indices, and measured four ecosystem services (water retention, soil retention, carbon storage, and biodiversity conservation) with the InVEST models. Furthermore, correlation analysis and global spatial autocorrelation coefficient were used to analyze the impact of landscape pattern changes on ecosystem services. The results showed grassland and farmland areas had continuously decreased, while built-up land and affected water had significantly increased. Landscape fragmentation was reduced, the connectivity between patches was weakened, landscape heterogeneity, evenness, and patch irregularity were increased. Changes in landscape composition and configuration have affected the ecosystem services of the Huaihe River Basin. The reduction in grassland areas and the increase in built-up land areas have significantly reduced the capacity for soil retention, carbon storage, and biodiversity conservation. Spatially, regions with low landscape fragmentation and high patch connectivity had a higher water retention capacity and biodiversity conservation, while soil retention and carbon storage were opposite. Temporally, reduction of landscape fragmentation and increase of patch shape irregularity had a negative effect on water retention, carbon storage, and biodiversity conservation, while soil retention was not sensitive to these changes. The findings in this paper promote an understanding of the relationship between landscape patterns and ecosystem services on a large scale and provide theoretical guidance for ecosystem management and protection planning in the Huaihe River Basin, China.

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Liu, M., K. Rajagopalan, S. H. Chung, X. Jiang, J. Harrison, T. Nergui, A. Guenther, et al. "What is the importance of climate model bias when projecting the impacts of climate change on land surface processes?" Biogeosciences 11, no. 10 (May 16, 2014): 2601–22. http://dx.doi.org/10.5194/bg-11-2601-2014.

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Abstract. Regional climate change impact (CCI) studies have widely involved downscaling and bias correcting (BC) global climate model (GCM)-projected climate for driving land surface models. However, BC may cause uncertainties in projecting hydrologic and biogeochemical responses to future climate due to the impaired spatiotemporal covariance of climate variables and a breakdown of physical conservation principles. Here we quantify the impact of BC on simulated climate-driven changes in water variables (evapotranspiration (ET), runoff, snow water equivalent (SWE), and water demand for irrigation), crop yield, biogenic volatile organic compounds (BVOC), nitric oxide (NO) emissions, and dissolved inorganic nitrogen (DIN) export over the Pacific Northwest (PNW) region. We also quantify the impacts on net primary production (NPP) over a small watershed in the region (HJ-Andrews). Simulation results from the coupled ECHAM5–MPI-OM model with A1B emission scenario were first dynamically downscaled to 12 km resolution with the WRF model. Then a quantile-mapping-based statistical downscaling model was used to downscale them into 1/16° resolution daily climate data over historical and future periods. Two climate data series were generated, with bias correction (BC) and without bias correction (NBC). Impact models were then applied to estimate hydrologic and biogeochemical responses to both BC and NBC meteorological data sets. These impact models include a macroscale hydrologic model (VIC), a coupled cropping system model (VIC-CropSyst), an ecohydrological model (RHESSys), a biogenic emissions model (MEGAN), and a nutrient export model (Global-NEWS). Results demonstrate that the BC and NBC climate data provide consistent estimates of the climate-driven changes in water fluxes (ET, runoff, and water demand), VOCs (isoprene and monoterpenes) and NO emissions, mean crop yield, and river DIN export over the PNW domain. However, significant differences rise from projected SWE, crop yield from dry lands, and HJ-Andrews's ET between BC and NBC data. Even though BC post-processing has no significant impacts on most of the studied variables when taking PNW as a whole, their effects have large spatial variations and some local areas are substantially influenced. In addition, there are months during which BC and NBC post-processing produces significant differences in projected changes, such as summer runoff. Factor-controlled simulations indicate that BC post-processing of precipitation and temperature both substantially contribute to these differences at regional scales. We conclude that there are trade-offs between using BC climate data for offline CCI studies versus directly modeled climate data. These trade-offs should be considered when designing integrated modeling frameworks for specific applications; for example, BC may be more important when considering impacts on reservoir operations in mountainous watersheds than when investigating impacts on biogenic emissions and air quality, for which VOCs are a primary indicator.

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Hu, Jun, Yichen Li, Tianliang Zhao, Jane Liu, Xiao-Ming Hu, Duanyang Liu, Yongcheng Jiang, Jianming Xu, and Luyu Chang. "An important mechanism of regional O3 transport for summer smog over the Yangtze River Delta in eastern China." Atmospheric Chemistry and Physics 18, no. 22 (November 15, 2018): 16239–51. http://dx.doi.org/10.5194/acp-18-16239-2018.

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Abstract. Severe ozone (O3) pollution episodes plague a few regions in eastern China at certain times of the year, e.g., the Yangtze River Delta (YRD). However, the formation mechanisms, including meteorological factors, contributing to these severe pollution events remain elusive. A severe summer smog stretched over the YRD region from 22 to 25 August 2016. This event displayed hourly surface O3 concentrations that exceeded 300 µg m−3 on 25 August in Nanjing, an urban area in the western YRD. The weather pattern during this period was characterized by near-surface prevailing easterly winds and continuous high air temperatures. The formation mechanism responsible for this O3 pollution episode over the YRD region, particularly the extreme values over the western YRD, was investigated using observation data and by running simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem). The results showed that the extremely high surface O3 concentration in the western YRD area on 25 August was largely due to regional O3 transport in the nocturnal residual layer (RL) and the diurnal change in the atmospheric boundary layer. On 24 August, high O3 levels, with peak values of 220 µg m−3, occurred in the daytime mixing layer over the eastern YRD region. During nighttime from 24 to 25 August, a shallow stable boundary layer formed near the surface which decoupled the RL above it from the surface. Ozone in the decoupled RL remained quite constant, which resulted in an O3-rich “reservoir” forming in this layer. This reservoir persisted due to the absence of O3 consumption from nitrogen oxide (NO) titration or dry deposition during nighttime. The prevailing easterly winds in the lower troposphere governed the regional transport of this O3-rich air mass in the nocturnal RL from the eastern to the western YRD. As the regional O3 transport reached the RL over the western YRD, O3 concentrations in the RL accumulated and rose to 200 µg m−3 over the western Nanjing site during the sunrise hours on 25 August. The development of the daytime convective boundary layer after sunrise resulted in the disappearance of the RL, as the vertical mixing in the convective boundary layer uniformly redistributed O3 from the upper levels via the entrainment of O3-rich RL air down to the O3-poor air at the ground. This net downward transport flux reached up to 35 µg m−3 h−1, and contributed a considerable surface O3 accumulation, resulting in severe daytime O3 pollution during the summer smog event on 25 August in the western YRD region. The mechanism of regional O3 transport through the nocturnal RL revealed in this study has great implications regarding understanding O3 pollution and air quality change.

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