Journal articles on the topic 'Hydrological flux'
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1
Zhou, Wen-Jun, Hua-Zheng Lu, Yi-Ping Zhang, Li-Qing Sha, Douglas Allen Schaefer, Qing-Hai Song, Yun Deng, and Xiao-Bao Deng. "Hydrologically transported dissolved organic carbon influences soil respiration in a tropical rainforest." Biogeosciences 13, no. 19 (October 4, 2016): 5487–97. http://dx.doi.org/10.5194/bg-13-5487-2016.
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Abstract. To better understand the effect of dissolved organic carbon (DOC) transported by hydrological processes (rainfall, throughfall, litter leachate, and surface soil water; 0–20 cm) on soil respiration in tropical rainforests, we detected the DOC flux in rainfall, throughfall, litter leachate, and surface soil water (0–20 cm), compared the seasonality of δ13CDOC in each hydrological process, and δ13C in leaves, litter, and surface soil, and analysed the throughfall, litter leachate, and surface soil water (0–20 cm) effect on soil respiration in a tropical rainforest in Xishuangbanna, south-west China. Results showed that the surface soil intercepted 94.4 ± 1.2 % of the annual litter leachate DOC flux and is a sink for DOC. The throughfall and litter leachate DOC fluxes amounted to 6.81 and 7.23 % of the net ecosystem exchange respectively, indicating that the DOC flux through hydrological processes is an important component of the carbon budget, and may be an important link between hydrological processes and soil respiration in a tropical rainforest. Even the variability in soil respiration is more dependent on the hydrologically transported water than DOC flux insignificantly, soil temperature, and soil-water content (at 0–20 cm). The difference in δ13C between the soil, soil water (at 0–20 cm), throughfall, and litter leachate indicated that DOC is transformed in the surface soil and decreased the sensitivity indices of soil respiration of DOC flux to water flux, which suggests that soil respiration is more sensitive to the DOC flux in hydrological processes, especially the soil-water DOC flux, than to soil temperature or soil moisture.
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Brownlee, James, Pallav Ray, Mukul Tewari, and Haochen Tan. "Relative Role of Turbulent and Radiative Flux on the Near-Surface Temperature in a Single-Layer Urban Canopy Model over Houston." Journal of Applied Meteorology and Climatology 56, no. 8 (August 2017): 2173–87. http://dx.doi.org/10.1175/jamc-d-17-0088.1.
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AbstractNumerical simulations without hydrological processes tend to overestimate the near-surface temperatures over urban areas. This is presumably due to underestimation of surface latent heat flux. To test this hypothesis, the existing single-layer urban canopy model (SLUCM) within the Weather Research and Forecasting Model is evaluated over Houston, Texas. Three simulations were conducted during 24–26 August 2000. The simulations include the use of the default “BULK” urban scheme, the SLUCM without hydrological processes, and the SLUCM with hydrological processes. The results show that the BULK scheme was least accurate, and it overestimated the near-surface temperatures and winds over the urban regions. In the presence of urban hydrological processes, the SLUCM underestimates these parameters. An analysis of the surface heat fluxes suggests that the error in the BULK scheme is due to a lack of moisture at the urban surface, whereas the error in the SLUCM with hydrological processes is due to increases in moisture at the urban surface. These results confirm earlier studies in which changes in near-surface temperature were primarily due to the changes in the turbulent (latent and sensible heat) fluxes in the presence of hydrological processes. The contribution from radiative flux was about one-third of that from turbulent flux. In the absence of hydrological processes, however, the results indicate that the changes in radiative flux contribute more to the near-surface temperature changes than the turbulent heat flux. The implications of these results are discussed.
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McCormack, T., O. Naughton, P. M. Johnston, and L. W. Gill. "Quantifying the nutrient flux within a lowland karstic catchment." Hydrology and Earth System Sciences Discussions 12, no. 10 (October 9, 2015): 10221–60. http://dx.doi.org/10.5194/hessd-12-10221-2015.
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Abstract. Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over three years. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Within the turloughs, nutrient concentrations were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification during stable flooded periods (typically 3–4 months per year) was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly via sedimentation and subsequent soil deposition. The results from this study suggest that, in stable conditions, ephemeral lakes can impart considerable nutrient losses on a karst groundwater system.
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McCormack, T., O. Naughton, P. M. Johnston, and L. W. Gill. "Quantifying the nutrient flux within a lowland karstic catchment." Hydrology and Earth System Sciences Discussions 12, no. 1 (January 7, 2015): 93–134. http://dx.doi.org/10.5194/hessd-12-93-2015.
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Abstract. Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were collected and tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over a three year period. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Results indicated that at the system outlet to the sea, autogenic recharge had added approximately 35% to the total flow and approximately 85% to the total N-load. Within some turloughs, nutrient loads were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly within the diffuse/epikarst zone.
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Peters-Lidard, Christa D., Martyn Clark, Luis Samaniego, Niko E. C. Verhoest, Tim van Emmerik, Remko Uijlenhoet, Kevin Achieng, Trenton E. Franz, and Ross Woods. "Scaling, similarity, and the fourth paradigm for hydrology." Hydrology and Earth System Sciences 21, no. 7 (July 20, 2017): 3701–13. http://dx.doi.org/10.5194/hess-21-3701-2017.
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Abstract. In this synthesis paper addressing hydrologic scaling and similarity, we posit that roadblocks in the search for universal laws of hydrology are hindered by our focus on computational simulation (the third paradigm) and assert that it is time for hydrology to embrace a fourth paradigm of data-intensive science. Advances in information-based hydrologic science, coupled with an explosion of hydrologic data and advances in parameter estimation and modeling, have laid the foundation for a data-driven framework for scrutinizing hydrological scaling and similarity hypotheses. We summarize important scaling and similarity concepts (hypotheses) that require testing; describe a mutual information framework for testing these hypotheses; describe boundary condition, state, flux, and parameter data requirements across scales to support testing these hypotheses; and discuss some challenges to overcome while pursuing the fourth hydrological paradigm. We call upon the hydrologic sciences community to develop a focused effort towards adopting the fourth paradigm and apply this to outstanding challenges in scaling and similarity.
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Branfireun, B. A., and N. T. Roulet. "Controls on the fate and transport of methylmercury in a boreal headwater catchment, northwestern Ontario, Canada." Hydrology and Earth System Sciences 6, no. 4 (August 31, 2002): 785–94. http://dx.doi.org/10.5194/hess-6-785-2002.
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Abstract. The fate and transport of methylmercury (MeHg) were studied in a small boreal catchment. Hydrological processes largely govern the magnitude of the flux of MeHg. Seasonal and inter-annual variability in hydrology produce variable source strengths of MeHg throughout the catchment. The mass flux of MeHg within, and from the catchment is dependent on the mass flux of water and the relative placement of landscape units in the catchment hydrological cascade. Hydrology also governs the maintenance of the methylating environments in the catchment. Specifically, hydrological processes maintain zones of anoxia in both the catchment uplands and peatlands that support obligate anaerobic sulphate-reducing bacteria. In addition, groundwater flow paths are an essential control on the delivery of sulphate to these bacteria that facilitate in situ mercury methylation. Keywords: methylmercury, methylation, hydrology, boreal catchment, peatland, Ontario, Canada
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Antico, Andrés, Olivier Marchal, Lawrence A. Mysak, and Françoise Vimeux. "Milankovitch Forcing and Meridional Moisture Flux in the Atmosphere: Insight from a Zonally Averaged Ocean–Atmosphere Model." Journal of Climate 23, no. 18 (September 15, 2010): 4841–55. http://dx.doi.org/10.1175/2010jcli3273.1.
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Abstract A 1-Myr-long time-dependent solution of a zonally averaged ocean–atmosphere model subject to Milankovitch forcing is examined to gain insight into long-term changes in the planetary-scale meridional moisture flux in the atmosphere. The model components are a one-dimensional (latitudinal) atmospheric energy balance model with an active hydrological cycle and an ocean circulation model representing four basins (Atlantic, Indian, Pacific, and Southern Oceans). This study finds that the inclusion of an active hydrological cycle does not significantly modify the responses of annual-mean air and ocean temperatures to Milankovitch forcing found in previous integrations with a fixed hydrological cycle. Likewise, the meridional overturning circulation of the North Atlantic Ocean is not significantly affected by hydrological changes. Rather, it mainly responds to precessionally driven variations of ocean temperature in subsurface layers (between 70- and 500-m depth) of this basin. On the other hand, annual and zonal means of evaporation rate and meridional flux of moisture in the atmosphere respond notably to obliquity-driven changes in the meridional gradient of annual-mean insolation. Thus, when obliquity is decreased (increased), the meridional moisture flux in the atmosphere is intensified (weakened). This hydrological response is consistent with deuterium excess records from polar ice cores, which are characterized by dominant obliquity cycles.
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SHIMIZU, Yuta, Shin-ichi ONODERA, and Kenji MATSUMORI. "Estimating nitrogen flux from a watershed using hydrological model." Journal of Japanese Association of Hydrological Sciences 44, no. 4 (2014): 207–23. http://dx.doi.org/10.4145/jahs.44.207.
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Quinn, P. F., B. Ostendorf, K. Beven, and J. Tenhunen. "Spatial and temporal predictions of soil moisture patterns and evaporative losses using TOPMODEL and the GASFLUX model for an Alaskan catchment." Hydrology and Earth System Sciences 2, no. 1 (March 31, 1998): 51–64. http://dx.doi.org/10.5194/hess-2-51-1998.
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Abstract. By using topographic indices as derived from a Digital Terrain Models (DTM), it is possible to represent the heterogeneity within a landscape. This heterogeneity can reflect both long term evolutionary patterns seen in a landscape and the short term forcing of flow dynamics during storm events. By spatial analysis, the linkage between the geomorphological- hydrological-plant physiological phenomena can be examined. In this study, a direct link will be established between the topographically-driven hydrological phenomena and the eco-physiological response. The topographic distribution function of TOPMODEL is used to control the spatial and temporal flux of the channel flow and water table. The plant physiological model GAS-FLUX is used to give a spatially and temporally dissaggregated species-sensitive estimate of evapotranspiration flux. Evapotranspiration is sensitive to the vegetation phonology, to tundra community physiology and to the temperature regime. A simple linking of TOPMODEL and the GAS-FLUX model is applied to a summer snow-free period to the Imnavait catchment, Alaska (2.2 km2). A species-sensitive evapotranspiration model proved to give the highest quality results when validated against flow observations. Predicted dynamics of variable source area and the component hydrological processes are illustrated.
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Johansson, Markus, Saija Saarni, and Jouni Sorvari. "Ultra-High-Resolution Monitoring of the Catchment Response to Changing Weather Conditions Using Online Sediment Trapping." Quaternary 2, no. 2 (May 12, 2019): 18. http://dx.doi.org/10.3390/quat2020018.
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The purpose of this study was to identify relationships between meteorological and hydrological observations and sediment flux rate changes, in order to better understand catchment dynamics. The meteorological and hydrological observations included local air temperature, wind speed, water temperature, and ice cover, while the sediment flux rate was observed in the lake basin using a modified sediment trap technique. This study demonstrates the advantages of a new online methodology applied in conventional sediment trapping to obtain flux rate information with daily resolution. A prototype of a high-resolution online sediment trap was tested in Savilahti Bay, Lake Kallavesi, eastern Finland, during the period from 22 October 2017 to 6 October 2018. The daily resolutions of meteorological, hydrological, and sediment flux rate data were analyzed using statistical methods. The results indicate relationships between temperature, precipitation, wind speed, and sediment flux rate, but the urban site also showed erosional changes due to anthropogenic land use. Sediment flux ceased during winter season and spring floods were recorded as pronounced peaks in sediment flux, while the growing season showed generally higher sediment accumulation rates. This research also provides valuable information on the catchment response to short-term weather events. The influence of a storm led to larger sediment flux for several days. The importance of wind speed and frost formation on sedimentation, which has been difficult to address due to trap deployment times of typically several months, is now supported. Used together with varved sediment archives, online sediment trapping will facilitate the interpretation of paleoclimatic proxy records and modeling of detailed weather and erosion conditions that are related to climate change.
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Goeller, S., M. Thoma, K. Grosfeld, and H. Miller. "A balanced water layer concept for subglacial hydrology in large scale ice sheet models." Cryosphere Discussions 6, no. 6 (December 17, 2012): 5225–53. http://dx.doi.org/10.5194/tcd-6-5225-2012.
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Abstract. There is currently no doubt about the existence of a wide-spread hydrological network under the Antarctic ice sheet, which lubricates the ice base and thus leads to increased ice velocities. Consequently, ice models should incorporate basal hydrology to obtain meaningful results for future ice dynamics and their contribution to global sea level rise. Here, we introduce the balanced water layer concept, covering two prominent subglacial hydrological features for ice sheet modeling on a continental scale: the evolution of subglacial lakes and balance water fluxes. We couple it to the thermomechanical ice-flow model RIMBAY and apply it to a synthetic model domain inspired by the Gamburtsev Mountains, Antarctica. In our experiments we demonstrate the dynamic generation of subglacial lakes and their impact on the velocity field of the overlaying ice sheet, resulting in a negative ice mass balance. Furthermore, we introduce an elementary parametrization of the water flux–basal sliding coupling and reveal the predominance of the ice loss through the resulting ice streams against the stabilizing influence of less hydrologically active areas. We point out, that established balance flux schemes quantify these effects only partially as their ability to store subglacial water is lacking.
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Goeller, S., M. Thoma, K. Grosfeld, and H. Miller. "A balanced water layer concept for subglacial hydrology in large-scale ice sheet models." Cryosphere 7, no. 4 (July 13, 2013): 1095–106. http://dx.doi.org/10.5194/tc-7-1095-2013.
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Abstract. There is currently no doubt about the existence of a widespread hydrological network under the Antarctic Ice Sheet, which lubricates the ice base and thus leads to increased ice velocities. Consequently, ice models should incorporate basal hydrology to obtain meaningful results for future ice dynamics and their contribution to global sea level rise. Here, we introduce the balanced water layer concept, covering two prominent subglacial hydrological features for ice sheet modeling on a continental scale: the evolution of subglacial lakes and balance water fluxes. We couple it to the thermomechanical ice-flow model RIMBAY and apply it to a synthetic model domain. In our experiments we demonstrate the dynamic generation of subglacial lakes and their impact on the velocity field of the overlaying ice sheet, resulting in a negative ice mass balance. Furthermore, we introduce an elementary parametrization of the water flux–basal sliding coupling and reveal the predominance of the ice loss through the resulting ice streams against the stabilizing influence of less hydrologically active areas. We point out that established balance flux schemes quantify these effects only partially as their ability to store subglacial water is lacking.
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Kreye, Phillip, Marlene Gelleszun, Manickam Somasundaram, and Günter Meon. "Classification of Hydrological Relevant Parameters by Soil Hydraulic Behaviour." Geosciences 9, no. 5 (May 8, 2019): 206. http://dx.doi.org/10.3390/geosciences9050206.
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Soil water simulations on hydrological meso- or macroscale require parameters that describe the physical characteristics of the soil. At these scales, information regarding soil properties is mostly only available on very coarse spatial resolutions with texture based soil characterisations, where it is difficult to select representative soil hydraulic parameters. We improved the parameter estimation by introducing a new soil classification system, which is based on soil hydraulic behaviour in order to realistically reproduce the soil water interaction within meso-scaled hydrological models. The time series of soil water flux were simulated based on one million different parameterisations, which were then utilised for similarity analyses while applying the k-means clustering. The resulting classes show a different pattern when compared to the United States Department of Agriculture (USDA) texture based classes. Representative time series of water flux representative of the new classes were compared to time series of the USDA texture classification. The new classes show remarkably lower uncertainties. The bandwidth of the time series within a class is orders of magnitudes higher for the USDA system when compared to the new system. The evaluation of similarity of the simulated water flux time series within one and the same class were also clearly better for the new system.
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Koirala, Sujan, Hyungjun Kim, Yukiko Hirabayashi, Shinjiro Kanae, and Taikan Oki. "Sensitivity of Global Hydrological Simulations to Groundwater Capillary Flux Parameterizations." Water Resources Research 55, no. 1 (January 2019): 402–25. http://dx.doi.org/10.1029/2018wr023434.
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Dewey, Janet, Jeff Hatten, Byoungkoo Choi, Clay Mangum, and Ying Ouyang. "Climate Drivers and Sources of Sediment and Organic Matter Fluxes in Intermittent Rivers and Ephemeral Streams (IRES) of a Subtropical Watershed, USA." Climate 8, no. 10 (October 16, 2020): 117. http://dx.doi.org/10.3390/cli8100117.
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Climate-driven hydrological models rarely incorporate intermittent rivers and ephemeral streams (IRES) due to monitoring difficulties and their perceived minor effect on river networks. Worldwide, IRES represent approximately 50% of river networks and up to 60% of annual flow and are recognized as conduits and processors of organic matter (OM). Climate induced changes in precipitation and discharge (Q) may impact OM fluxes from IRES. We assessed storm-driven source and flux of total suspended solids (TSS) and OM from small IRES in Mississippi, USA. We used linear Pearson correlations to evaluate relationships between water and storm characteristics (e.g., discharge). Stepwise regression was used to predict change in flux. Dissolved OM was derived from saturated flow through soil whereas particulate OM was derived from channel extension during storms. A power log relationship between Q and materials flux indicated that Q was the driver for flux. A 5% increase in Q within IRES may result in flux increase of 2% TSS and 1.7–2.8% OM. Climate change projections of increased storm intensity over a shorter water year will increase channel extension and soil water transfer resulting in higher material flux to downstream reaches. Climate-driven hydrological models of OM flux should incorporate IRES.
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Li, Guangwei, Xianhong Meng, Eleanor Blyth, Hao Chen, Lele Shu, Zhaoguo Li, Lin Zhao, and Yingsai Ma. "Impact of Fully Coupled Hydrology-Atmosphere Processes on Atmosphere Conditions: Investigating the Performance of the WRF-Hydro Model in the Three River Source Region on the Tibetan Plateau, China." Water 13, no. 23 (December 2, 2021): 3409. http://dx.doi.org/10.3390/w13233409.
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The newly developed WRF-Hydro model is a fully coupled atmospheric and hydrological processes model suitable for studying the intertwined atmospheric hydrological processes. This study utilizes the WRF-Hydro system on the Three-River source region. The Nash-Sutcliffe efficiency for the runoff simulation is 0.55 compared against the observed daily discharge amount of three stations. The coupled WRF-Hydro simulations are better than WRF in terms of six ground meteorological elements and turbulent heat flux, compared to the data from 14 meteorological stations located in the plateau residential area and two flux stations located around the lake. Although WRF-Hydro overestimates soil moisture, higher anomaly correlation coefficient scores (0.955 versus 0.941) were achieved. The time series of the basin average demonstrates that the hydrological module of WRF-hydro functions during the unfrozen period. The rainfall intensity and frequency simulated by WRF-Hydro are closer to global precipitation mission (GPM) data, attributed to higher convective available potential energy (CAPE) simulated by WRF-Hydro. The results emphasized the necessity of a fully coupled atmospheric-hydrological model when investigating land-atmosphere interactions on a complex topography and hydrology region.
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Tziperman, Eli, and Hezi Gildor. "The Stabilization of the Thermohaline Circulation by the Temperature–Precipitation Feedback." Journal of Physical Oceanography 32, no. 9 (September 1, 2002): 2707–14. http://dx.doi.org/10.1175/1520-0485-32.9.2707.
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Abstract The meridional freshwater flux in the atmosphere, and hence the strength of the hydrological cycle, undergoes variations on glacial–interglacial as well as on some shorter timescales. A significant portion of these changes to the hydrological cycle are due to the temperature–precipitation feedback according to which there is more precipitation over the higher latitudes during warm periods when the moisture holding capacity of the atmosphere is higher. It is proposed here that this feedback may play an important role in determining the stability of the thermohaline circulation (THC). The THC stability to different parameterizations of the meridional atmospheric freshwater flux is therefore investigated using a simple box model of the ocean, atmosphere, and sea ice. It is demonstrated that parameterizations that are consistent with the temperature–precipitation feedback, and hence with the observed variations of the hydrological cycle during glacial–interglacial cycles, stabilize the THC for a wide range of forcing parameters.
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van Nooijen, R. R. P., and A. G. Kolechkina. "A problem in hydrological model calibration in the case of averaged flux input and flux output." Environmental Modelling & Software 37 (November 2012): 167–78. http://dx.doi.org/10.1016/j.envsoft.2012.03.017.
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Westhoff, M. C., and E. Zehe. "Maximum entropy production: can it be used to constrain conceptual hydrological models?" Hydrology and Earth System Sciences Discussions 9, no. 10 (October 9, 2012): 11551–81. http://dx.doi.org/10.5194/hessd-9-11551-2012.
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Abstract. In recent years, optimality principles have been proposed to constrain hydrological models. The principle of Maximum Entropy Production (MEP) is one of the proposed principles and is subject of this study. It states that a steady state system is organized in such a way that entropy production is maximized. However, within hydrology, tests against observations are still missing. The aim of this paper is to test the MEP principle to reduce equifinality of a simple conceptual (bucket) model. We used the principle of maximizing power, which is equivalent to MEP when a constant temperature is assumed. Power is determined by multiplying a flux with its gradient. We thus defined for each flux in the model a gradient and checked if parameter sets that maximize power also reproduce the observed water balance. Subsequently we concluded that with the used model concept, this does not work. It would be easy to reject the MEP hypothesis to explain our findings, but we believe that our test is incomplete. By referring to the flaws in our own model concept, we believe that many issues can be learned about how to use MEP to constrain hydrological models. Among others, the most important are: (1) fluxes should be defined as a gradient divided by a resistance, where the flux feeds back on the gradient; (2) there should be a trade-off between two or more different fluxes, where, in principle, only one resistance can be optimized and (3) each process should have the right degrees of freedom: what are the feedbacks on this flux and what limits the flux?
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McCormack, T., O. Naughton, P. M. Johnston, and L. W. Gill. "Quantifying the influence of surface water–groundwater interaction on nutrient flux in a lowland karst catchment." Hydrology and Earth System Sciences 20, no. 5 (June 1, 2016): 2119–33. http://dx.doi.org/10.5194/hess-20-2119-2016.
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Abstract. Nutrient contamination of surface waters and groundwaters is an issue of growing importance as the risks associated with agricultural run-off escalate due to increasing demands on global food production. In this study, the influence of surface water–groundwater interaction on the nutrient flux in a lowland karst catchment was investigated with the aid of alkalinity sampling and a hydrological model. The objective of the study was to determine the impact of ephemeral karst lakes (turloughs) on the surface water–groundwater nutrient flux, and whether these lakes act as sources or sinks of nutrients within the groundwater flow system. Water samples were tested from a variety of rivers, turloughs, boreholes and springs at monthly intervals over 3 years. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenically and autogenically derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Within the turloughs, recorded nutrient concentrations were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this would not occur under conservative conditions. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification during stable flooded periods (typically 3–4 months per year) was deemed to be the main process reducing nitrogen concentrations within the turloughs, whereas phosphorus loss is thought to occur mostly via sedimentation and subsequent soil deposition. The results from this study suggest that, in stable conditions, ephemeral lakes can impart considerable nutrient losses on a karst groundwater system.
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Chevuturi, Amulya, Nicholas P. Klingaman, Andrew G. Turner, Liang Guo, and Pier Luigi Vidale. "Projected Changes in the East Asian Hydrological Cycle for Different Levels of Future Global Warming." Atmosphere 13, no. 3 (March 1, 2022): 405. http://dx.doi.org/10.3390/atmos13030405.
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Recent decades have shown significant changes to the hydrological cycle over East Asia (EA), and further changes are expected due to future global warming. This study evaluates projected seasonal changes in the EA hydrological cycle using simulations that are 1.5 °C, 2.0 °C and 3.0 ∘C warmer than pre-industrial, from the Met Office Unified Model (MetUM) Global Ocean Mixed Layer model version 2.0 (GOML2.0), compared against present-day conditions. The moisture sources of the warming-induced precipitation changes are identified over five hydrologically unique regions within EA. Precipitation over EA increases with warming (except over southeastern EA in the spring and autumn) due to the intensified hydrological cycle. The projected seasonal changes in the hydrological cycle are usually nonlinear, with the rate of change between 1.5 ∘C and 2.0 ∘C larger than the rate of change between 2.0 ∘C and 3.0 ∘C of warming. The warming-induced precipitation increases are mainly associated with an increase in remote moisture convergence rather than local moisture recycling, except over the Tibetan Plateau. Decomposition of the changes in moisture sources by direction and flux component indicate that changes from the west are dominated by changes to moisture and changes from the north are more circulation driven. The changes from the south are moisture driven over southern EA and driven by moisture and circulation change over northern EA. Our results highlight the regionally and seasonally diverse projected changes to the EA hydrological cycle due to global warming, which will be useful for region-specific climate mitigation policies and the implementation of seasonally varying adaptation methods.
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Han, Heechan, Jungho Kim, V. Chandrasekar, Jeongho Choi, and Sanghun Lim. "Modeling Streamflow Enhanced by Precipitation from Atmospheric River Using the NOAA National Water Model: A Case Study of the Russian River Basin for February 2004." Atmosphere 10, no. 8 (August 14, 2019): 466. http://dx.doi.org/10.3390/atmos10080466.
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This study aims to address hydrological processes and impacts of an atmospheric river (AR) event that occurred during 15–18 February 2004 in the Russian River basin in California. The National Water Model (NWM), a fully distributed hydrologic model, was used to evaluate the hydrological processes including soil moisture flux, overland flow, and streamflow. Observed streamflow and volumetric soil water content data were used to evaluate the performance of the NWM using various error metrics. The simulation results showed that this AR event (15–18 February 2004) with a long duration of precipitation could cause not only deep soil saturation, but also high direct runoff depth. Taken together, the analysis revealed the complex interaction between precipitation and land surface response to the AR event. The results emphasize the significance of a change of water contents in various soil layers and suggest that soil water content monitoring could aid in improving flood forecasting accuracy caused by the extreme events such as the AR.
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Samaniego, Luis, Rohini Kumar, Stephan Thober, Oldrich Rakovec, Matthias Zink, Niko Wanders, Stephanie Eisner, et al. "Toward seamless hydrologic predictions across spatial scales." Hydrology and Earth System Sciences 21, no. 9 (September 1, 2017): 4323–46. http://dx.doi.org/10.5194/hess-21-4323-2017.
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Abstract. Land surface and hydrologic models (LSMs/HMs) are used at diverse spatial resolutions ranging from catchment-scale (1–10 km) to global-scale (over 50 km) applications. Applying the same model structure at different spatial scales requires that the model estimates similar fluxes independent of the chosen resolution, i.e., fulfills a flux-matching condition across scales. An analysis of state-of-the-art LSMs and HMs reveals that most do not have consistent hydrologic parameter fields. Multiple experiments with the mHM, Noah-MP, PCR-GLOBWB, and WaterGAP models demonstrate the pitfalls of deficient parameterization practices currently used in most operational models, which are insufficient to satisfy the flux-matching condition. These examples demonstrate that J. Dooge's 1982 statement on the unsolved problem of parameterization in these models remains true. Based on a review of existing parameter regionalization techniques, we postulate that the multiscale parameter regionalization (MPR) technique offers a practical and robust method that provides consistent (seamless) parameter and flux fields across scales. Herein, we develop a general model protocol to describe how MPR can be applied to a particular model and present an example application using the PCR-GLOBWB model. Finally, we discuss potential advantages and limitations of MPR in obtaining the seamless prediction of hydrological fluxes and states across spatial scales.
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Brunet, R. C., and K. Brian Astin. "Variation in phosphorus flux during a hydrological season: the River Adour." Water Research 32, no. 3 (March 1998): 547–58. http://dx.doi.org/10.1016/s0043-1354(97)00317-5.
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Zhang, Hua, Kevan B. Moffett, Lisamarie Windham-Myers, and Steven M. Gorelick. "Hydrological Controls on Methylmercury Distribution and Flux in a Tidal Marsh." Environmental Science & Technology 48, no. 12 (May 28, 2014): 6795–804. http://dx.doi.org/10.1021/es500781g.
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Baumgarten, Manuela, Wendelin Weis, Angelika Kühn, Katharina May, and Rainer Matyssek. "Forest transpiration—targeted through xylem sap flux assessment versus hydrological modeling." European Journal of Forest Research 133, no. 4 (March 11, 2014): 677–90. http://dx.doi.org/10.1007/s10342-014-0796-4.
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Moatar, Florentina, Michel Meybeck, Sébastien Raymond, François Birgand, and Florence Curie. "River flux uncertainties predicted by hydrological variability and riverine material behaviour." Hydrological Processes 27, no. 25 (August 2, 2012): 3535–46. http://dx.doi.org/10.1002/hyp.9464.
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Achite, Mohammed, and Sylvain Ouillon. "Recent changes in climate, hydrology and sediment load in the Wadi Abd, Algeria (1970–2010)." Hydrology and Earth System Sciences 20, no. 4 (April 6, 2016): 1355–72. http://dx.doi.org/10.5194/hess-20-1355-2016.
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Abstract. Here we investigate the changes of temperature, precipitation, river runoff and sediment transport in the Wadi Abd in northwest Algeria over a time series of 40 hydrological years (1970–2010). Temperature increased and precipitation decreased with the reduction in rainfall being relatively higher during the rainy season. A shift towards an earlier onset of first rains during summer was also found with cascading effects on hydrology (hydrological regimes, vegetation, etc.) and thus on erosion and sediment yield. During the 1980s, the flow regime shifted from perennial to intermittent with an amplification of the variations of discharge and a modification of the sediment regime with higher and more irregular suspended particulate flux. Sediment flux was shown to almost double every decade from the 1970s to the 2000s. The sediment regime shifted from two equivalent seasons of sediment yield (spring and fall) to a single major season regime. In the 2000s, autumn produced over 4 times more sediment than spring. The enhanced scatter of the C–Q pairs denotes an increase of hysteresis phenomena in the Wadi Abd that is probably related to the change in the hydrologic regime. At the end of the period, due to irregularity of the discharge, the ability of a rating curve to derive suspended sediment concentration from river discharge was poor.
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Tang, Qiuhong, Taikan Oki, Shinjiro Kanae, and Heping Hu. "The Influence of Precipitation Variability and Partial Irrigation within Grid Cells on a Hydrological Simulation." Journal of Hydrometeorology 8, no. 3 (June 1, 2007): 499–512. http://dx.doi.org/10.1175/jhm589.1.
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Abstract The effects of natural and anthropogenic heterogeneity on a hydrological simulation are evaluated using a distributed biosphere hydrological model (DBHM) system. The DBHM embeds a biosphere model into a distributed hydrological scheme, representing both topography and vegetation in a mesoscale hydrological simulation, and the model system includes an irrigation scheme. The authors investigated the effects of two kinds of variability, precipitation variability and the variability of irrigation redistributing runoff, representing natural and anthropogenic heterogeneity, respectively, on hydrological processes. Runoff was underestimated if rainfall was placed spatially uniformly over large grid cells. Accounting for precipitation heterogeneity improved the runoff simulation. However, the negative runoff contribution, namely, the situation that mean annual precipitation is less than evapotranspiration, cannot be simulated by only considering the natural heterogeneity. This constructive model shortcoming can be eliminated by accounting for anthropogenic heterogeneity caused by irrigation water withdrawals. Irrigation leads to increased evapotranspiration and decreased runoff, and surface soil moisture in irrigated areas increases because of irrigation. Simulations performed for the Yellow River basin of China indicated streamflow decreases of 41% due to irrigation effects. The latent heat flux in the peak irrigation season [June–August (JJA)] increased 3.3 W m−2 with a decrease in the ground surface temperature of 0.1 K for the river basin. The maximum simulated increase in the latent heat flux was 43 W m−2, and the ground temperature decrease was 1.6 K in the peak irrigation season.
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Loritz, Ralf, Axel Kleidon, Conrad Jackisch, Martijn Westhoff, Uwe Ehret, Hoshin Gupta, and Erwin Zehe. "A topographic index explaining hydrological similarity by accounting for the joint controls of runoff formation." Hydrology and Earth System Sciences 23, no. 9 (September 18, 2019): 3807–21. http://dx.doi.org/10.5194/hess-23-3807-2019.
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Abstract. Surface topography is an important source of information about the functioning and form of a hydrological landscape. Because of its key role in explaining hydrological processes and structures, and also because of its wide availability at good resolution in the form of digital elevation models (DEMs), it is frequently used to inform hydrological analyses. Not surprisingly, several hydrological indices and models have been proposed for linking geomorphic properties of a landscape with its hydrological functioning; a widely used example is the “height above the nearest drainage” (HAND) index. From an energy-centered perspective HAND reflects the gravitational potential energy of a given unit mass of water located on a hillslope, with the reference level set to the elevation of the nearest corresponding river. Given that potential energy differences are the main drivers for runoff generation, HAND distributions provide important proxies to explain runoff generation in catchments. However, as expressed by the second law of thermodynamics, the driver of a flux explains only one aspect of the runoff generation mechanism, with the driving potential of every flux being depleted via entropy production and dissipative energy loss. In fact, such losses dominate when rainfall becomes runoff, and only a tiny portion of the driving potential energy is actually transformed into the kinetic energy of streamflow. In recognition of this, we derive a topographic index called reduced dissipation per unit length index (rDUNE) by reinterpreting and enhancing HAND following a straightforward thermodynamic argumentation. We compare rDUNE with HAND, and with the frequently used topographic wetness index (TWI), and show that rDUNE provides stronger discrimination of catchments into groups that are similar with respect to their dominant runoff processes. Our analysis indicates that accounting for both the driver and resistance aspects of flux generation provides a promising approach for linking the architecture of a system with its functioning and is hence an appropriate basis for developing similarity indices in hydrology.
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Achite, M., and S. Ouillon. "Recent changes in climate, hydrology and sediment load in the Wadi Abd, Algeria (1970–2010)." Hydrology and Earth System Sciences Discussions 12, no. 10 (October 14, 2015): 10457–513. http://dx.doi.org/10.5194/hessd-12-10457-2015.
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Abstract. Here we investigate the changes of temperature, precipitation, river runoff and sediment transport in the Wadi Abd in NW Algeria over a time series of 40 hydrological years (1970–2010). Temperature increased and precipitation decreased with the reduction in rainfall being relatively higher during the rainy season. A shift towards an earlier onset of first rains during summer was also found with cascading effects on hydrology (hydrological regimes, vegetation etc) and thus on erosion and sediment yield. During the 1980s, the flow regime shifted from perennial to intermittent with an amplification of the variations of discharge and a modification of the sediment regime with higher and more irregular suspended particulate flux. Sediment flux was shown to almost double every decade from 1970s to 2000s. The sediment regime shifted from two equivalent seasons of sediment delivery (spring and autumn) to a single major season regime. In 2000s, autumn produced over 4 times more sediment than spring. The enhanced scatter denotes an increase of hysteresis phenomena in the Wadi Abd that is probably related to the change in the hydrologic regime. The increased erosion of the watershed is accompanied by a decrease in the coefficient b of its rating curves and a decrease in the erosive power of the river. At the end of the period, due to the irregularity of the discharge, the ability of a rating curve to derive suspended sediment concentration from river discharge was poor.
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Remy, Frédérique, and Benoît Legresy. "Subglacial hydrological networks in Antarctica and their impact on ice flow." Annals of Glaciology 39 (2004): 67–72. http://dx.doi.org/10.3189/172756404781814401.
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AbstractDeep beneath the thick ice cover of the Antarctic continent there exist subglacial hydrological networks, within which basal meltwater can flow. In this paper, we use surface elevation data from European Remote-sensing Satellite radar altimetry to map these subglacial hydrological networks for the whole continent. We observe a confused pattern of subglacial systems, linking regions where basal melting takes place. In some regions, channels can be followed over some hundreds of kilometres. Some of these meet the ice-sheet margin, suggesting that meltwater can be transported all the way to the ocean. We observe an east–west gradient in the distribution of hydrological networks that could be explained by the geothermal flux pattern.
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Schuurmans, J. M., P. A. Troch, A. A. Veldhuizen, W. G. M. Bastiaanssen, and M. F. P. Bierkens. "Assimilation of remotely sensed latent heat flux in a distributed hydrological model." Advances in Water Resources 26, no. 2 (February 2003): 151–59. http://dx.doi.org/10.1016/s0309-1708(02)00089-1.
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Llubes, Muriel, Cédric Lanseau, and Frédérique Rémy. "Relations between basal condition, subglacial hydrological networks and geothermal flux in Antarctica." Earth and Planetary Science Letters 241, no. 3-4 (January 2006): 655–62. http://dx.doi.org/10.1016/j.epsl.2005.10.040.
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Unwin, H. Juliette T., Garth N. Wells, and Andrew W. Woods. "dissolution in a background hydrological flow." Journal of Fluid Mechanics 789 (January 26, 2016): 768–84. http://dx.doi.org/10.1017/jfm.2015.752.
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During $\text{CO}_{2}$ sequestration into a deep saline aquifer of finite vertical extent, $\text{CO}_{2}$ will tend to accumulate in structural highs such as offered by an anticline. Over times of tens to thousands of years, some of the $\text{CO}_{2}$ will dissolve into the underlying groundwater to produce a region of relatively dense, saturated water directly below the plume of $\text{CO}_{2}$. Continued dissolution then requires the supply of unsaturated aquifer water. In an aquifer of finite vertical extent, this may be provided by a background hydrological flow, or a laterally-spreading buoyancy-driven flow caused by the greater density of the $\text{CO}_{2}$ saturated water relative to the original aquifer water.We investigate long time steady-state dissolution in the presence of a background hydrological flow. In steady state, the distribution of $\text{CO}_{2}$ in the groundwater upstream of the aquifer involves a balance between three competing effects: (i) the buoyancy-driven flow of $\text{CO}_{2}$ saturated water; (ii) the diffusion of $\text{CO}_{2}$ from saturated to under-saturated water; and (iii) the advection associated with the oncoming background flow. This leads to three limiting regimes. In the limit of very slow diffusion, a nearly static intrusion of dense fluid may extend a finite distance upstream, balanced by the pressure gradient associated with the oncoming background flow. In the limit of fast diffusion relative to the flow, a gradient zone may become established in which the along-aquifer diffusive flux balances the advection associated with the background flow. However, if the buoyancy-driven flow speed exceeds the background hydrological flow speed, then a third, intermediate regime may become established. In this regime, a convective recirculation develops upstream of the anticline involving the vertical diffusion of $\text{CO}_{2}$ from an upstream propagating flow of dense $\text{CO}_{2}$ saturated water into the downstream propagating flow of $\text{CO}_{2}$ unsaturated water. For each limiting case, we find analytical solutions for the distribution of $\text{CO}_{2}$ upstream of the anticline, and test our analysis with full numerical simulations. A key result is that, although there may be very different controls on the distribution and extent of $\text{CO}_{2}$ bearing water upstream of the anticline, in each case the dissolution rate is given by the product of the background volume flux and the difference in concentration between the $\text{CO}_{2}$ saturated water and the original aquifer water upstream.
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Maheu, Audrey, Islem Hajji, François Anctil, Daniel F. Nadeau, and René Therrien. "Using the maximum entropy production approach to integrate energy budget modelling in a hydrological model." Hydrology and Earth System Sciences 23, no. 9 (September 20, 2019): 3843–63. http://dx.doi.org/10.5194/hess-23-3843-2019.
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Abstract. Total terrestrial evaporation, also referred to as evapotranspiration, is a key process for understanding the hydrological impacts of climate change given that warmer surface temperatures translate into an increase in the atmospheric evaporative demand. To simulate this flux, many hydrological models rely on the concept of potential evaporation (PET), although large differences have been observed in the response of PET models to climate change. The maximum entropy production (MEP) model of land surface fluxes offers an alternative approach for simulating terrestrial evaporation in a simple way while fulfilling the physical constraint of energy budget closure and providing a distinct estimation of evaporation and transpiration. The objective of this work is to use the MEP model to integrate energy budget modelling within a hydrological model. We coupled the MEP model with HydroGeoSphere (HGS), an integrated surface and subsurface hydrologic model. As a proof of concept, we performed one-dimensional soil column simulations at three sites of the AmeriFlux network. The coupled model (HGS-MEP) produced realistic simulations of soil water content (root-mean-square error – RMSE – between 0.03 and 0.05 m3 m−3; NSE – Nash–Sutcliffe efficiency – between 0.30 and 0.92) and terrestrial evaporation (RMSE between 0.31 and 0.71 mm d−1; NSE between 0.65 and 0.88) under semi-arid, Mediterranean and temperate climates. At the daily timescale, HGS-MEP outperformed the stand-alone HGS model where total terrestrial evaporation is derived from potential evaporation, which we computed using the Penman–Monteith equation, although both models had comparable performance at the half-hourly timescale. This research demonstrated the potential of the MEP model to improve the simulation of total terrestrial evaporation in hydrological models, including for hydrological projections under climate change.
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Rodriguez, Daniel Andrés, and Iracema F. Albuquerque Cavalcanti. "Simulations of the Hydrological Cycle over Southern South America Using the CPTEC/COLA AGCM." Journal of Hydrometeorology 7, no. 5 (October 1, 2006): 916–36. http://dx.doi.org/10.1175/jhm534.1.
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Abstract The La Plata River basin is the second largest basin of South America after the Amazon basin, and it is located in an international area that occupies territories of Argentina, Uruguay, Brazil, Paraguay, and Bolivia, areas of great economic activity. In the present work, the water budget over the region was studied and the atmospheric and terrestrial components were analyzed to investigate the Center for Weather Forecast and Climate Studies/Center for Ocean–Land–Atmosphere Studies (CPTEC/COLA) atmospheric general circulation model (AGCM) behavior in a simulation of 10 yr. The analysis was performed considering two sectors, northern and southern, because of their different behaviors, and the main characteristics were simulated by the model. The northern sector presents a well-defined annual cycle with well-established wet conditions in the summer, when there is development of the South Atlantic convergence zone (SACZ). In the southern sector, there is a weak annual cycle and the hydrological variables do not have large seasonal variations as in the northern sector. A period of maximum precipitation is identified at the end of spring in the southern sector. Moisture flux convergence (MFC) in the model occurs over southeast Brazil during summer and over northern Argentina in the spring, consistent with observations. Analysis of the meridional and zonal moisture fluxes reveals that there is an intrusion of moisture from the tropical region, southward, and also flux from the Atlantic Ocean, that feed both sectors. The flux from the Amazon region was the main source of external moisture during the summer season, while the flux from the Atlantic Ocean was dominant during winter. Additional analysis of El Niño 1982/83 and La Niña 1988/89 episodes showed the importance of Amazon and Atlantic moisture fluxes to the La Plata basin region. During El Niño 1982/83 there was more moisture flux from the Amazon region to the southern sector than during La Niña 1988/89. This feature was related to droughts during La Niña and floods during El Niño in the La Plata region.
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Zhang, Zhicai, Xi Chen, Qinbo Cheng, and Chris Soulsby. "Storage dynamics, hydrological connectivity and flux ages in a karst catchment: conceptual modelling using stable isotopes." Hydrology and Earth System Sciences 23, no. 1 (January 7, 2019): 51–71. http://dx.doi.org/10.5194/hess-23-51-2019.
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Abstract. We developed a new tracer-aided hydrological model that disaggregates cockpit karst terrain into the two dominant landscape units of hillslopes and depressions (with fast and slow flow systems). The new model was calibrated by using high temporal resolution hydrometric and isotope data in the outflow of Chenqi catchment in Guizhou Province of south-western China. The model could track hourly water and isotope fluxes through each landscape unit and estimate the associated storage and water age dynamics. From the model results we inferred that the fast flow reservoir in the depression had the smallest water storage and the slow flow reservoir the largest, with the hillslope intermediate. The estimated mean ages of water draining the hillslope unit, and the fast and slow flow reservoirs during the study period, were 137, 326 and 493 days, respectively. Distinct seasonal variability in hydroclimatic conditions and associated water storage dynamics (captured by the model) were the main drivers of non-stationary hydrological connectivity between the hillslope and depression. During the dry season, slow flow in the depression contributes the largest proportion (78.4 %) of flow to the underground stream draining the catchment, resulting in weak hydrological connectivity between the hillslope and depression. During the wet period, with the resulting rapid increase in storage, the hillslope unit contributes the largest proportion (57.5 %) of flow to the underground stream due to the strong hydrological connectivity between the hillslope and depression. Meanwhile, the tracer-aided model can be used to identify the sources of uncertainty in the model results. Our analysis showed that the model uncertainty of the hydrological variables in the different units relies on their connectivity with the outlet when the calibration target uses only the outlet information. The model uncertainty was much lower for the “newer” water from the fast flow system in the depression and flow from the hillslope unit during the wet season and higher for “older” water from the slow flow system in the depression. This suggests that to constrain model parameters further, increased high-resolution hydrometric and tracer data on the internal dynamics of systems (e.g. groundwater responses during low flow periods) could be used in calibration.
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Hrachowitz, M., H. Savenije, T. A. Bogaard, D. Tetzlaff, and C. Soulsby. "What can flux tracking teach us about water age distribution patterns and their temporal dynamics?" Hydrology and Earth System Sciences 17, no. 2 (February 7, 2013): 533–64. http://dx.doi.org/10.5194/hess-17-533-2013.
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Abstract. The complex interactions of runoff generation processes underlying the hydrological response of streams remain not entirely understood at the catchment scale. Extensive research has demonstrated the utility of tracers for both inferring flow path distributions and constraining model parameterizations. While useful, the common use of linearity assumptions, i.e. time invariance and complete mixing, in these studies provides only partial understanding of actual process dynamics. Here we use long-term (<20 yr) precipitation, flow and tracer (chloride) data of three contrasting upland catchments in the Scottish Highlands to inform integrated conceptual models investigating different mixing assumptions. Using the models as diagnostic tools in a functional comparison, water and tracer fluxes were then tracked with the objective of exploring the differences between different water age distributions, such as flux and resident water age distributions, and characterizing the contrasting water age pattern of the dominant hydrological processes in the three study catchments to establish an improved understanding of the wetness-dependent temporal dynamics of these distributions. The results highlight the potential importance of partial mixing processes which can be dependent on the hydrological functioning of a catchment. Further, tracking tracer fluxes showed that the various components of a model can be characterized by fundamentally different water age distributions which may be highly sensitive to catchment wetness history, available storage, mixing mechanisms, flow path connectivity and the relative importance of the different hydrological processes involved. Flux tracking also revealed that, although negligible for simulating the runoff response, the omission of processes such as interception evaporation can result in considerably biased water age distributions. Finally, the modeling indicated that water age distributions in the three study catchments do have long, power-law tails, which are generated by the interplay of flow path connectivity, the relative importance of different flow paths as well as by the mixing mechanisms involved. In general this study highlights the potential of customized integrated conceptual models, based on multiple mixing assumptions, to infer system internal transport dynamics and their sensitivity to catchment wetness states.
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Bettella, Francesco, Vincenzo D'Agostino, and Lucia Bortolini. "Drainage flux simulation of green roofs under wet conditions." Journal of Agricultural Engineering 49, no. 4 (December 19, 2018): 242–52. http://dx.doi.org/10.4081/jae.2018.838.
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The role of green roofs in reducing drainage fluxes is known, but despite extensive analysis in the literature, methods to predict the hydrologic performance for a given green roof composition are scarce. These methods are useful for the hydraulic design and for planning regulations that impose specific hydrological responses. This research investigates on the prediction of the drainage fluxes produced below a green roof with initial water content equal to its water retention capacity (worst-case scenario). Laboratory tests were performed to analyse the rainfall-drainage relationship for green-roof and single components (growing media and drainage storage layers) under specific rainfall intensities. Two types of largely used drainage/storage layers and growth media were analysed, both singularly and in combination. The experiments consider two rainfall events lasting 10 min with constant intensity. The results indicate that the Curve Number (CN) method (U.S. Soil Conservation Service) with a simple adaptation can be used to reproduce the green-roof hydrologic behaviour under antecedent moisture conditions comparable with those of the experiments. In fact, the water retention capacity, controlling the water-output initiation below the green roof, can be used as threshold variable of a step function, above which the CN method is applicable and below which drainage fluxes are practically null. Through this position, the CN assignment for a composite greenroof can be consistently estimated using the proprieties of the single components (drainage/storage layer and growing medium) and it provides values that are very close to those of waterproof media and quite higher than those suggested in companion researches. Drainage amounts are predicted with a standard error equal to 1.50 mm, which corresponds to 5.7% of the mean value observed. After rain initiation, the steady state condition of the drainage flux has proved to be markedly affected by the growing medium and drainage layer composing the system, which result effective in discriminating the green roof performance.
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Guzinski, R., H. Nieto, S. Stisen, and R. Fensholt. "Inter-comparison of energy balance and hydrological models for land surface energy flux estimation over a whole river catchment." Hydrology and Earth System Sciences 19, no. 4 (April 24, 2015): 2017–36. http://dx.doi.org/10.5194/hess-19-2017-2015.
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Abstract. Evapotranspiration (ET) is the main link between the natural water cycle and the land surface energy budget. Therefore water-balance and energy-balance approaches are two of the main methodologies for modelling this process. The water-balance approach is usually implemented as a complex, distributed hydrological model, while the energy-balance approach is often used with remotely sensed observations of, for example, the land surface temperature (LST) and the state of the vegetation. In this study we compare the catchment-scale output of two remote sensing models based on the two-source energy-balance (TSEB) scheme, against a hydrological model, MIKE SHE, calibrated over the Skjern river catchment in western Denmark. The three models utilize different primary inputs to estimate ET (LST from different satellites in the case of remote sensing models and modelled soil moisture and heat flux in the case of the MIKE SHE ET module). However, all three of them use the same ancillary data (meteorological measurements, land cover type and leaf area index, etc.) and produce output at similar spatial resolution (1 km for the TSEB models, 500 m for MIKE SHE). The comparison is performed on the spatial patterns of the fluxes present within the catchment area as well as on temporal patterns on the whole catchment scale in 8-year long time series. The results show that the spatial patterns of latent heat flux produced by the remote sensing models are more similar to each other than to the fluxes produced by MIKE SHE. The temporal patterns produced by the remote sensing and hydrological models are quite highly correlated (r &approx; 0.8). This indicates potential benefits to the hydrological modelling community of integrating spatial information derived through remote sensing methodology (contained in the ET maps derived with the energy-balance models, satellite based LST or another source) into the hydrological models. How this could be achieved and how to evaluate the improvements, or lack of thereof, is still an open research question.
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Zeng, Zhi, Yufang Wu, Zhijie Chen, Quanjia Huang, Yinghui Wang, and Yang Luo. "Runoff Estimation of Jiulong River Based on Acoustic Doppler Current Profiler Online Monitoring Data and Its Implication for Pollutant Flux Estimation." International Journal of Environmental Research and Public Health 19, no. 23 (December 6, 2022): 16363. http://dx.doi.org/10.3390/ijerph192316363.
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The runoff of the Jiulong River (JLR) is a key parameter that affects the estimation of pollutant flux into Xiamen Bay (XMB). The precise runoff estimation of the JLR can be used to determine the accuracy of the pollutant flux estimation flowing into XMB. In this study, to analyze the hydrological dynamic characteristics and identify the correlation between fixed-site real-time ocean current observations and cross-sectional navigation flow observations, we conducted six navigation observations on two cross-sections of the JLR estuary during the spring tide and neap tide in the normal season, wet season, and dry season in 2020. Simultaneously, we measured hydrological observation data by a fixed-site buoy located in the JLR estuary and collected runoff data that were measured upstream of the JLR. The results showed that the average correlation coefficient between the average velocity of the fixed-point buoy and average velocity of the section was more than 0.90, higher than expected, the minimum average deviation was 4%, and the minimum sample standard error was 5.7%, which was a good result. In this study, we constructed a model for estimating the runoff of the JLR into the sea. The findings demonstrated that Acoustic Doppler Current Profiler (ADCP) online monitoring data were useful to estimate runoff of the JLR with high accuracy, could promote the accuracy of estimated pollutant flux of the JLR’s discharge into XMB, and could provide more scientific and reliable basic data for future load flux estimation research.
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Montenegro, S. M. G. L., B. B. da Silva, A. C. D. Antonino, J. R. S. Lima, E. S. de Souza, L. M. M. de Oliveira, A. E. S. S. de Moura, and R. M. S. Souza. "Hydrological studies in experimental and representative basins in Pernambuco State, Brazil." Proceedings of the International Association of Hydrological Sciences 364 (September 16, 2014): 422–28. http://dx.doi.org/10.5194/piahs-364-422-2014.
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Abstract. Hydrological studies in experimental and representative basins are of fundamental importance for water resources management. This paper presents some activities of hydrological research in experimental and representative basins of the State of Pernambuco, Brazil. The study areas are located at Tapacurá and Mundaú representative basins and at the Gameleira experimental basin, and in experimental plots in Pajeú basin. In the Tapacurá basin, three studies were performed: (1) different monthly coefficients "k" of the Thornthwaite method were tested to calculate the effective temperature and, consequently, the reference evapotranspiration, giving rise to the method identified as Modified Thornthwaite; (2) the spatial variability of the retention curve and hydraulic conductivity parameters were analysed using the Beerkan method; (3) changes in vegetation cover were evaluated through the NDVI and NDWI indexes using TM–Landsat 5 images. In the Mundaú representative basin, the performance of different evapotranspiration methods was evaluated and compared to the FAO standard method, Penman-Monteith. In the Pajeú basin, the experimental plot is covered by pasture and sensors were installed to monitor the following variables: rainfall, air temperature, the energy balance components (net radiation, latent and sensible heat, and soil heat flux), wind velocity and CO2 flux into atmosphere, soil moisture and runoff.
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Western, Andrew W., and Rodger B. Grayson. "The Tarrawarra Data Set: Soil moisture patterns, soil characteristics, and hydrological flux measurements." Water Resources Research 34, no. 10 (October 1998): 2765–68. http://dx.doi.org/10.1029/98wr01833.
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Wang, Wang, and Zhang. "Interplays between State and Flux Hydrological Variables across Vadose Zones: A Numerical Investigation." Water 11, no. 6 (June 20, 2019): 1295. http://dx.doi.org/10.3390/w11061295.
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Knowledge of both state (e.g., soil moisture) and flux (e.g., actual evapotranspiration (ETa) and groundwater recharge (GR)) hydrological variables across vadose zones is critical for understanding ecohydrological and land-surface processes. In this study, a one-dimensional process-based vadose zone model with generated soil hydraulic parameters was utilized to simulate soil moisture, ETa, and GR. Daily hydrometeorological data were obtained from different climate zones to drive the vadose zone model. On the basis of the field phenomenon of soil moisture temporal stability, reasonable soil moisture spatiotemporal structures were reproduced from the model. The modeling results further showed that the dependence of ETa and GR on soil hydraulic properties varied considerably with climatic conditions. In particular, the controls of soil hydraulic properties on ETa and GR greatly weakened at the site with an arid climate. In contrast, the distribution of mean relative difference (MRD) of soil moisture was still significantly correlated with soil hydraulic properties (most notably residual soil moisture content) under arid climatic conditions. As such, the correlations of MRD with ETa and GR differed across different climate regimes. In addition, the simulation results revealed that samples with average moisture conditions did not necessarily produce average values of ETa and GR (and vice versa), especially under wet climatic conditions. The loose connection between average state and flux hydrological variables across vadose zones is partly because of the high non-linearity of subsurface processes, which leads to the complex interactions of soil moisture, ETa, and GR with soil hydraulic properties. This study underscores the importance of using soil moisture information from multiple sites for inferring areal average values of ETa and GR, even with the knowledge of representative sites that can be used to monitor areal average moisture conditions.
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Walker, Jeffrey P., Garry R. Willgoose, and Jetse D. Kalma. "The Nerrigundah Data Set: Soil moisture patterns, soil characteristics, and hydrological flux measurements." Water Resources Research 37, no. 11 (November 2001): 2653–58. http://dx.doi.org/10.1029/2001wr000545.
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Ficchì, Andrea, Charles Perrin, and Vazken Andréassian. "Hydrological modelling at multiple sub-daily time steps: Model improvement via flux-matching." Journal of Hydrology 575 (August 2019): 1308–27. http://dx.doi.org/10.1016/j.jhydrol.2019.05.084.
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Syvitski, James P. M. "Supply and flux of sediment along hydrological pathways: research for the 21st century." Global and Planetary Change 39, no. 1-2 (October 2003): 1–11. http://dx.doi.org/10.1016/s0921-8181(03)00008-0.
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Quinton, William, Aaron Berg, Michael Braverman, Olivia Carpino, Laura Chasmer, Ryan Connon, James Craig, et al. "A synthesis of three decades of hydrological research at Scotty Creek, NWT, Canada." Hydrology and Earth System Sciences 23, no. 4 (April 24, 2019): 2015–39. http://dx.doi.org/10.5194/hess-23-2015-2019.
Full textAbstract:
Abstract. Scotty Creek, Northwest Territories (NWT), Canada, has been the focus of hydrological research for nearly three decades. Over this period, field and modelling studies have generated new insights into the thermal and physical mechanisms governing the flux and storage of water in the wetland-dominated regions of discontinuous permafrost that characterises much of the Canadian and circumpolar subarctic. Research at Scotty Creek has coincided with a period of unprecedented climate warming, permafrost thaw, and resulting land cover transformations including the expansion of wetland areas and loss of forests. This paper (1) synthesises field and modelling studies at Scotty Creek, (2) highlights the key insights of these studies on the major water flux and storage processes operating within and between the major land cover types, and (3) provides insights into the rate and pattern of the permafrost-thaw-induced land cover change and how such changes will affect the hydrology and water resources of the study region.
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Oshima, Kazuhiro, and Koji Yamazaki. "Atmospheric hydrological cycles in the Arctic and Antarctic during the past four decades." Czech Polar Reports 7, no. 2 (June 1, 2017): 169–80. http://dx.doi.org/10.5817/cpr2017-2-17.
Full textAbstract:
Atmospheric hydrological cycles over the Arctic and Antarctic have been investigated in the previous studies and there are some similarity and dissimilarity in the two polar regions. The Arctic and Antarctic are areas of moisture flux convergence through the year. So the precipitation (P) exceeds the evaporation (E) and the net precipitation (P-E) is positive. Therefore, the atmospheric moisture transport is a primary input of water into the polar regions. Meanwhile the climatological seasonal cycles of P-E over these regions are dominated by transient moisture flux associated with cyclone activities, the interannual variations are governed by the stationary flux associated with the Arctic Oscillation and the Antarctic Oscillation (AAO). In addition, recent climate changes influence the polar hydrological cycles. Our analyses using an atmospheric reanalysis up to recent years indicated that there were no significant long-term changes in the poleward moisture transport into both the Arctic and Antarctic during 1979-2016. On the other hand, the water vapor (precipitable water) were clearly increasing over the Arctic and gradually decreasing over the Antarctic during the same period. As expected, the increasing trend of water vapor was due to the large warming over the Arctic. There were two reasons for the gradually decreasing trend of water vapor over the Antarctic. The first one was the positive trend of AAO in summer and the second was deepening trend of the Amundsen low in autumn. The trends in water vapor and temperature during the past 38 years further suggest that both polar regions were getting dryer in several seasons. The trend, however, needs to be confirmed by follow-up climatological analyses.