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Yadav, R. K., K. Rupa Kumar, and M. Rajeevan. "Climate change scenarios for Northwest India winter season." Quaternary International 213, no. 1-2 (February 2010): 12–19. http://dx.doi.org/10.1016/j.quaint.2008.09.012.
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RATHORE, L. S., K. K. SINGH, S. A. SASEENDRAN, and A. K. BAXLA. "Modelling the impact of climate change on rice production in India." MAUSAM 52, no. 1 (December 29, 2021): 263–74. http://dx.doi.org/10.54302/mausam.v52i1.1693.
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The CERES-Rice crop simulation model, calibrated and validated for the varieties PR106 in NW India. IR36 in central India and Jaya in south India, is used for nalysing the effect of climate change on rice productivity in the country. Plausible climate change scenario for the Indian subcontinent as expected by the middle of the next century taking into account the projected emissions of greenhouse gases and sulphate aerosols, in a coupled atmosphere-ocean model experiment performed at Deutsches Klimarechenzentrum, Germany, is adopted for the study. The adopted scenario represented an increase in monsoon seasonal mean surface temperature of the order of about 1.5° C over the south India and 1°C over northwest and central India in the decade 2040-49 with respect to the 1980s and an increase in rainfall of the order of 2 mm per day over south India while the simulated decrease of the order about -1 mm and -1.5 mm over northwest and central India respectively. The IPCC Business-as-usual scenario projection of plant usable concentration of CO2 about 460 PPM by the middle fo the next century are also used in the crop model simulation (CERES - Rice V3 Model).
Simulation studies carried out with the climate change scenarios over different parts of the country are analysed and interpreted.
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V.P. PRAMOD, B. BAPUJI RAO, S.S.V.S. RAMAKRISHNA, M. MUNESHWAR SINGH, N.R. PATEL, V.M. SANDEEP, V.U.M. RAO, P. S. CHOWDARY, V. NARSIMHA RAO, and P. VIJAYA KUMAR. "Impact of projected climate on wheat yield in India and its adaptation strategies." Journal of Agrometeorology 19, no. 3 (September 1, 2017): 207–16. http://dx.doi.org/10.54386/jam.v19i3.627.
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Wheat is highly sensitive to climate change especially temperature changes experienced in the later phase of crop season. Hence, it is of immense importance to know how and to what extent climate change will affect wheat yields and to assess the adaptive strategies for mitigating possible negative consequences on wheat production. Wheat yield responses to three future climatic periods (2025, 2050 and 2075) were studied by driving DSSAT-Wheat (v4.5) model with daily weather from three CMIP-5 climate models’ (GFDL-ESM2M, MIROC5, and NorESM1-M) as the basic input at four sites (Ludhiana, Raipur, Akola and New Delhi) representing three major wheat growing zones of the country. Projected changes in growing season (November-March) day and night temperatures at four sites differed substantially both in direction and magnitude. Day temperatures are projected to rise conspicuously at Ludhiana, representing northwest parts of the country, and moderately over central parts of India (Akola and Raipur). Positive rainfall anomalies at Ludhiana (+76%) and negative anomalies at Raipur (-15%) are projected in future climates. With these anticipated changes, wheat is likely to experience warmer days (+1.1 °C) at Ludhiana and nights at Raipur (+2.8 °C) and more seasonal moisture availability at Ludhiana in future climates. Negative impacts of climatic change in these sites are found to be minimized by adapting one or a combination of management practices, which are site specific.
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van Oldenborgh, Geert Jan, Sjoukje Philip, Sarah Kew, Michiel van Weele, Peter Uhe, Friederike Otto, Roop Singh, Indrani Pai, Heidi Cullen, and Krishna AchutaRao. "Extreme heat in India and anthropogenic climate change." Natural Hazards and Earth System Sciences 18, no. 1 (January 24, 2018): 365–81. http://dx.doi.org/10.5194/nhess-18-365-2018.
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Abstract. On 19 May 2016 the afternoon temperature reached 51.0 °C in Phalodi in the northwest of India – a new record for the highest observed maximum temperature in India. The previous year, a widely reported very lethal heat wave occurred in the southeast, in Andhra Pradesh and Telangana, killing thousands of people. In both cases it was widely assumed that the probability and severity of heat waves in India are increasing due to global warming, as they do in other parts of the world. However, we do not find positive trends in the highest maximum temperature of the year in most of India since the 1970s (except spurious trends due to missing data). Decadal variability cannot explain this, but both increased air pollution with aerosols blocking sunlight and increased irrigation leading to evaporative cooling have counteracted the effect of greenhouse gases up to now. Current climate models do not represent these processes well and hence cannot be used to attribute heat waves in this area. The health effects of heat are often described better by a combination of temperature and humidity, such as a heat index or wet bulb temperature. Due to the increase in humidity from irrigation and higher sea surface temperatures (SSTs), these indices have increased over the last decades even when extreme temperatures have not. The extreme air pollution also exacerbates the health impacts of heat. From these factors it follows that, from a health impact point of view, the severity of heat waves has increased in India. For the next decades we expect the trend due to global warming to continue but the surface cooling effect of aerosols to diminish as air quality controls are implemented. The expansion of irrigation will likely continue, though at a slower pace, mitigating this trend somewhat. Humidity will probably continue to rise. The combination will result in a strong rise in the temperature of heat waves. The high humidity will make health effects worse, whereas decreased air pollution would decrease the impacts.
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Arumugam, Surendran, Ashok K.R., Suren N. Kulshreshtha., Isaac Vellangany, and Ramu Govindasamy. "Yield variability in rainfed crops as influenced by climate variables." International Journal of Climate Change Strategies and Management 7, no. 4 (November 16, 2015): 442–59. http://dx.doi.org/10.1108/ijccsm-08-2013-0096.
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Purpose – This paper aims to explore the impact of climate change on yields and yield variances in major rainfed crops and measure possible changes in yields under projected climate changes in different agro-climatic zones of Tamil Nadu, India. Although many empirical studies report the influence of climate change on crop yield, only few address the effect on yield variances. Even in such cases, the reported yield variances were obtained through simulation studies rather than from actual observations. In this context, the present study analyzes the impact of climate change on crops yield and yield variance using the observed yields. Design/methodology/approach – The Just-Pope yield function (1978) is used to analyze the impact of climate change on mean yield and variance. The estimated coefficient from Just-Pope yield function and the projected climatic data for the year 2030 are incorporated to capture the projected changes in crop yield and variances. Findings – By the year 2030, the yield of pulses is estimated to decline in all the zones (Northeast, Northwest, Western, Cauvery delta, South and Southern zones), with significant declines in the Northeast zone (6.07 per cent), Cauvery delta zone (3.55 per cent) and South zone (3.54 per cent). Sorghum yield may suffer more in Western zone (2.63 per cent), Southern zone (1.92 per cent) and Northeast zone (1.62 per cent). Moreover, the yield of spiked millet is more likely to decrease in the Southern zone (1.39 per cent), Northeast zone (1.21 per cent) and Cauvery delta zone (0.24 per cent), and the yield of cotton may also decline in the Northeast zone (12.99 per cent), Northwest zone (8.05 per cent) and Western zone (2.10 per cent) of Tamil Nadu, India. Originality/value – The study recommends introducing appropriate crop insurance policies to address possible financial losses to the farmers. Prioritizing area-specific stress-tolerant crop varieties without complementing yield would sustain crops cultivation further.
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Mira Shivani, S., S. Srivastava, and A. Singh. "Critical analysis of hydrological mass variations of northwest India." IOP Conference Series: Earth and Environmental Science 1032, no. 1 (June 1, 2022): 012032. http://dx.doi.org/10.1088/1755-1315/1032/1/012032.
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Abstract With current climate change, water availability is a huge concern. Ground-water (GW) is depleting at a steep rate globally and more specifically in Northwest India. Estimation and analysis of GW availability would be of great use for formulating a proper water management plan for the future. The study is carried out in the north-western part of India with the aim of generating a time series for total water storage (TWS) using different remote sensing and model-based data like GRACE, Landsat, MODIS. From the time series, it is clear-cut that, the TWS is showing a declining trend and this might be due to depletion of groundwater as, other variables like precipitation, evapotranspiration, soil moisture (obtained from MERRA-2 and CFSR data) are not showing any negative trend during the study period (2002 - 2021). Also, from the change detection analysis of land use land cover maps and crop yield statistics of water-intensive crops it can be concluded that croplands in the study area are increasing denoting the usage of water for irrigation at a large scale. Thus, better management of the groundwater is required for avoiding severe water scarcity in the future.
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Petrie, Cameron A., Ravindra N. Singh, Jennifer Bates, Yama Dixit, Charly A. I. French, David A. Hodell, Penelope J. Jones, et al. "Adaptation to Variable Environments, Resilience to Climate Change: InvestigatingLand, Water and Settlementin Indus Northwest India." Current Anthropology 58, no. 1 (February 2, 2017): 1–30. http://dx.doi.org/10.1086/690112.
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Vu, Quyet Manh, and Tri Dan Nguyen. "Agroforestry Suitability Mapping for the Northwest Provinces of Vietnam." Proceedings 36, no. 1 (April 3, 2020): 142. http://dx.doi.org/10.3390/proceedings2019036142.
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This study aims to assess the potential development of selected agroforestry options for three provinces in the Northwest of Vietnam. Available spatial data including Land use/land cover maps and forest inventory maps were used as the base maps in combination with supplementary data and field survey to determine the potential agroforestry areas. Soil types, soil depth, soil texture, elevation, slope, temperature and rainfall were used to evaluate the biophysical suitability of ten typical agroforestry options in the study region. For assessing the impact of climate change to agroforestry suitability in the future, temperature and precipitation data extracted from two climate changes scenarios (Representative Concentration Pathway 4.5 and 8.5 in 2046–2065) were used. The results showed that the suitable areas for agroforestry development in Dien Bien, Sơn La and Yen Bai provinces were 267.74.01 ha, 405,597.96 ha; and 297,995.55 ha, respectively. Changes in temperature and precipitation by 2 climate change scenarios affected significantly to the suitability of Docynia indica + livestock grass, Teak + plum + coffee + grass and Plum + maize + livestock grass options. The map of agroforestry suitability can be served as a useful source in developing and expanding the area of agroforestry in the target provinces, and can be applied for other provinces in the same region in Vietnam.
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Phartiyal, Binita, Sheikh Nawaz Ali, Anupam Sharma, Shailesh Agrawal, Debarati Nag, Pooja Tiwari, Mohan Kumar, et al. "Palaeoclimatic variability during last eight millennia from a morainal lake in Zanskar, northwest Himalaya, India." Journal of Palaeosciences 71, no. 1 (July 22, 2022): 75–88. http://dx.doi.org/10.54991/jop.2022.545.
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Centennial–scale palaeoenvironmental variability has been deduced during past eight millennia using multi–proxy study (textural analysis, environmental magnetic parameters, stable carbon isotopes, palynofacies and elemental concentration), from Khangok–Padam in Zanskar Valley, northwest Himalaya. The multi–proxy record from this morainal lake spanning last ~8200 cal years BP has revealed four hydroclimatic phases. The overall progressively improving hydroclimatic trend is indicated by multi proxy study: sediment size/texture (as a proxy for the energy condition and depositional environment), mineral magnetism (proxy for sediment flux or lithogenic input and lithologic variation), carbon isotope signature (δ13Corg) preserved in organic constituents of sediments (a proxy for palaeovegetation and climate change), elemental geochemistry (proxy for weathering and erosion) and selected samples for palynofacies data (a proxy for changes in biological organic matter). This improving hydroclimatic trend is however punctuated by an abrupt wet spell at ~6200–5200 cal years BP and relatively drier climate during the Little Ice Age between 1400 and 1900 CE. The main driving force implicated for the changes are seen to be the solar output variations. The area lying in a transitional climatic zone of NW Himalaya shows no emphatic record of the events like the 4200 cal. years BP, 2600 cal. years BP and Holocene Climatic Optima. Contrary to the earlier studies in the region (e.g., Tsokar and TsoMorari), our results show an improving hydroclimatic condition in this transition climatic zone between the Indian Summer Monsoon dominated Higher and westerly dominated Trans Himalaya.
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Mukherjee, Avik, S. Y. Wang, and Parichart Promchote. "Examination of the Climate Factors That Reduced Wheat Yield in Northwest India during the 2000s." Water 11, no. 2 (February 18, 2019): 343. http://dx.doi.org/10.3390/w11020343.
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In India, a significant reduction of wheat yield would cause a widespread impact on food security for 1.35 billion people. The two highest wheat producing states, Punjab and Haryana in northern India, experienced a prolonged period of anomalously low wheat yield during 2002–2010. The extent of climate variability and change in influencing this prolonged reduction in wheat yield was examined. Daily air temperature (Tmax and Tave) was used to calculate the number of days above optimum temperature and growing degree days (GDD) anomaly. Two drought indices, the standard precipitation and evapotranspiration index and the radiation-based precipitation index, were used to describe the drought conditions. Groundwater variability was assessed via satellite-based approximation. The analysis results indicate that the wheat yield loss corresponds to the increase in the number of days with a temperature above 35 °C during the maturity stage (March). Reduction in monsoon rainfall led to a depletion of groundwater and reduced surface water for irrigation in the wheat growing season (November–March). Higher temperatures, coupled with water shortage and irregular irrigation, also appear to impact the yield reduction. In hindsight, improving the agronomic practices to minimize crop water usage could be an adaptation strategy to maintain the desired wheat yield in the face of climate-induced drought and precipitation anomaly.
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Sato, Tomonori, and Fujio Kimura. "How Does the Tibetan Plateau Affect the Transition of Indian Monsoon Rainfall?" Monthly Weather Review 135, no. 5 (May 1, 2007): 2006–15. http://dx.doi.org/10.1175/mwr3386.1.
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Abstract The roles of the Tibetan Plateau (TP) upon the transition of precipitation in the south Asian summer monsoon are investigated using a simplified regional climate model. Before the onset of the south Asian monsoon, descending flow in the midtroposphere, which can be considered as a suppressor against precipitation, prevails over northern India as revealed by the NCEP–NCAR reanalysis data. The descending motion gradually weakens and retreats from this region before July, consistent with the northwestward migration of the monsoon rainfall. To examine a hypothesis that the dynamical and thermal effects of TP cause the midtropospheric subsidence and its seasonal variation, a series of numerical experiments are conducted using a simplified regional climate model. The mechanical effect of the TP generates robust descending flow over northern India during winter and spring when the zonal westerly flow is relatively strong, but the effect becomes weaker after April as the westerly flow tends to be weaker. The thermal effect of the TP, contrastingly, enhances the descending flow over north India in the premonsoonal season. The descending flow enhanced by the thermal effect of the TP has a seasonal cycle because the global-scale upper-level westerly changes the energy propagation of the thermal forcing response. The subsidence formed by the mechanical and thermal effects of the TP disappears over northern India after the subtropical westerly shifts north of the plateau, the seasonal change of which is in good agreement with that in the reanalysis data. The retreat of the descending flow can be regarded as the withdrawal of the premonsoon season and the commencement of the south Asian monsoon. After that, the deep convection, indicating the onset of the Indian summer monsoon, is able to develop over north India in relation to the ocean–atmosphere and land–atmosphere interaction processes. Northwest India is known to be the latest region of summer monsoon onset in south Asia. Thus, the thermal and mechanical forcing of the TP has great impact on the transition of the Indian monsoon rainfall by changing the midtropospheric circulation.
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Bates, T. S., T. L. Anderson, T. Baynard, T. Bond, O. Boucher, G. Carmichael, A. Clarke, et al. "Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling." Atmospheric Chemistry and Physics 6, no. 6 (May 22, 2006): 1657–732. http://dx.doi.org/10.5194/acp-6-1657-2006.
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Abstract. The largest uncertainty in the radiative forcing of climate change over the industrial era is that due to aerosols, a substantial fraction of which is the uncertainty associated with scattering and absorption of shortwave (solar) radiation by anthropogenic aerosols in cloud-free conditions (IPCC, 2001). Quantifying and reducing the uncertainty in aerosol influences on climate is critical to understanding climate change over the industrial period and to improving predictions of future climate change for assumed emission scenarios. Measurements of aerosol properties during major field campaigns in several regions of the globe during the past decade are contributing to an enhanced understanding of atmospheric aerosols and their effects on light scattering and climate. The present study, which focuses on three regions downwind of major urban/population centers (North Indian Ocean (NIO) during INDOEX, the Northwest Pacific Ocean (NWP) during ACE-Asia, and the Northwest Atlantic Ocean (NWA) during ICARTT), incorporates understanding gained from field observations of aerosol distributions and properties into calculations of perturbations in radiative fluxes due to these aerosols. This study evaluates the current state of observations and of two chemical transport models (STEM and MOZART). Measurements of burdens, extinction optical depth (AOD), and direct radiative effect of aerosols (DRE – change in radiative flux due to total aerosols) are used as measurement-model check points to assess uncertainties. In-situ measured and remotely sensed aerosol properties for each region (mixing state, mass scattering efficiency, single scattering albedo, and angular scattering properties and their dependences on relative humidity) are used as input parameters to two radiative transfer models (GFDL and University of Michigan) to constrain estimates of aerosol radiative effects, with uncertainties in each step propagated through the analysis. Constraining the radiative transfer calculations by observational inputs increases the clear-sky, 24-h averaged AOD (34±8%), top of atmosphere (TOA) DRE (32±12%), and TOA direct climate forcing of aerosols (DCF – change in radiative flux due to anthropogenic aerosols) (37±7%) relative to values obtained with "a priori" parameterizations of aerosol loadings and properties (GFDL RTM). The resulting constrained clear-sky TOA DCF is −3.3±0.47, −14±2.6, −6.4±2.1 Wm−2 for the NIO, NWP, and NWA, respectively. With the use of constrained quantities (extensive and intensive parameters) the calculated uncertainty in DCF was 25% less than the "structural uncertainties" used in the IPCC-2001 global estimates of direct aerosol climate forcing. Such comparisons with observations and resultant reductions in uncertainties are essential for improving and developing confidence in climate model calculations incorporating aerosol forcing.
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Zheng, Yangxing, Mark A. Bourassa, and M. M. Ali. "The Impact of Rainfall on Soil Moisture Variability in Four Homogeneous Rainfall Zones of India during Strong, Weak, and Normal Indian Summer Monsoons." Water 14, no. 18 (September 8, 2022): 2788. http://dx.doi.org/10.3390/w14182788.
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This observational study mainly examines the impact of rainfall on Indian soil moisture (SM) variability in four homogeneous rainfall zones (i.e., central India (CI), northwest India (NWI), south peninsula India (SPIN), and northeast India (NEI)) as defined by India Meteorological Department (IMD) during strong, weak, and normal Indian summer monsoons (ISMs), which are determined regionally for each homogeneous rainfall zone separately. This study uses the daily gridded (0.25° × 0.25°) rainfall data set provided by IMD and the daily gridded (0.25° × 0.25°) SM combined product version 06.1 from European Space Agency Climate Change Initiative (ESA CCI) over the period 1992–2020. Results reveal that monthly and seasonal mean SM in NWI, CI, and SPIN are overall higher during strong than during weak ISMs. The daily SM and its dependence on rainfall appear to be region-locked in space and phase-locked in time: Strong correlation and large response to rainfall generally occur in most parts of SPIN and NWI during June (June–July) of strong (weak) ISMs where SM values are relatively small; Weak correlation and small response generally occur in CI and NEI in July-September (August–September) of strong (weak) ISMs where SM values are relatively large. The phase-locked feature is associated with the features of ISMs. The region-locked feature is presumably associated with the local features, such as soil and vegetation types and/or environmental conditions. Both region-locked and phase-locked features cause regional distinct features in SM persistence.
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Bates, T. S., T. L. Anderson, T. Baynard, T. Bond, O. Boucher, G. Carmichael, A. Clarke, et al. "Aerosol direct radiative effects over the northwest Atlantic, northwest Pacific, and North Indian Oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling." Atmospheric Chemistry and Physics Discussions 6, no. 1 (January 3, 2006): 175–362. http://dx.doi.org/10.5194/acpd-6-175-2006.
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Abstract. The largest uncertainty in the radiative forcing of climate change over the industrial era is that due to aerosols, a substantial fraction of which is the uncertainty associated with scattering and absorption of shortwave (solar) radiation by anthropogenic aerosols in cloud-free conditions (IPCC, 2001). Quantifying and reducing the uncertainty in aerosol influences on climate is critical to understanding climate change over the industrial period and to improving predictions of future climate change for assumed emission scenarios. Measurements of aerosol properties during major field campaigns in several regions of the globe during the past decade are contributing to an enhanced understanding of atmospheric aerosols and their effects on light scattering and climate. The present study, which focuses on three regions downwind of major urban/population centers (North Indian Ocean (NIO) during INDOEX, the Northwest Pacific Ocean (NWP) during ACE-Asia, and the Northwest Atlantic Ocean (NWA) during ICARTT), incorporates understanding gained from field observations of aerosol distributions and properties into calculations of perturbations in radiative fluxes due to these aerosols. This study evaluates the current state of observations and of two chemical transport models (STEM and MOZART). Measurements of burdens, extinction optical depth (AOD), and direct radiative effect of aerosols (DRE – change in radiative flux due to total aerosols) are used as measurement-model check points to assess uncertainties. In-situ measured and remotely sensed aerosol properties for each region (mixing state, mass scattering efficiency, single scattering albedo, and angular scattering properties and their dependences on relative humidity) are used as input parameters to two radiative transfer models (GFDL and University of Michigan) to constrain estimates of aerosol radiative effects, with uncertainties in each step propagated through the analysis. Constraining the radiative transfer calculations by observational inputs increases the clear-sky, 24-h averaged AOD (34±8%), top of atmosphere (TOA) DRE (32±12%), and TOA direct climate forcing of aerosols (DCF – change in radiative flux due to anthropogenic aerosols) (37±7%) relative to values obtained with "a priori" parameterizations of aerosol loadings and properties (GFDL RTM). The resulting constrained TOA DCF is −3.3±0.47, −14±2.6, −6.4±2.1 Wm−2 for the NIO, NWP, and NWA, respectively. Constraining the radiative transfer calculations by observational inputs reduces the uncertainty range in the DCF in these regions relative to global IPCC (2001) estimates by a factor of approximately 2. Such comparisons with observations and resultant reductions in uncertainties are essential for improving and developing confidence in climate model calculations incorporating aerosol forcing.
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Wang, Chuan-Yang, Shang-Ping Xie, and Yu Kosaka. "ENSO-Unrelated Variability in Indo–Northwest Pacific Climate: Regional Coupled Ocean–Atmospheric Feedback." Journal of Climate 33, no. 10 (May 15, 2020): 4095–108. http://dx.doi.org/10.1175/jcli-d-19-0426.1.
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AbstractRegional ocean–atmospheric interactions in the summer tropical Indo–northwest Pacific region are investigated using a tropical Pacific Ocean–global atmosphere pacemaker experiment with a coupled ocean–atmospheric model (cPOGA) and a parallel atmosphere model simulation (aPOGA) forced with sea surface temperature (SST) variations from cPOGA. Whereas the ensemble mean features pronounced influences of El Niño–Southern Oscillation (ENSO), the ensemble spread represents internal variability unrelated to ENSO. By comparing the aPOGA and cPOGA, this study examines the effect of the ocean–atmosphere coupling on the ENSO-unrelated variability. In boreal summer, ocean–atmosphere coupling induces local positive feedback to enhance the variance and persistence of the sea level pressure and rainfall variability over the northwest Pacific and likewise induces local negative feedback to suppress the variance and persistence of the sea level pressure and rainfall variability over the north Indian Ocean. Anomalous surface heat fluxes induced by internal atmosphere variability cause SST to change, and SST anomalies feed back onto the atmosphere through atmospheric convection. The local feedback is sensitive to the background winds: positive under the mean easterlies and negative under the mean westerlies. In addition, north Indian Ocean SST anomalies reinforce the low-level anomalous circulation over the northwest Pacific through atmospheric Kelvin waves. This interbasin interaction, along with the local feedback, strengthens both the variance and persistence of atmospheric variability over the northwest Pacific. The response of the regional Indo–northwest Pacific mode to ENSO and influences on the Asian summer monsoon are discussed.
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Anoop, T. R., V. Sanil Kumar, P. R. Shanas, G. Johnson, and M. M. Amrutha. "Indian Ocean Dipole modulated wave climate of eastern Arabian Sea." Ocean Science Discussions 12, no. 5 (October 27, 2015): 2473–96. http://dx.doi.org/10.5194/osd-12-2473-2015.
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Abstract. Intrinsic modes of variability have a significant role in driving climatic oscillations in the ocean. In this paper, we investigate the influence of inter-annual variability, the Indian Ocean Dipole (IOD), on the wave climate of the eastern Arabian Sea (AS). Using measured, modeled and reanalysis wave data and reanalysis wind data, we show that the IOD plays a major role in the variability of wave climate of the study region due to the IOD induced changes in equatorial sea surface temperature and sea level pressure. Inter-annual variability in the wave climate over the eastern AS during the IOD is due to the modification of winds from the northern AS. The change in wind field over the AS due to IOD influences the generation or dissipation of wave field and hence causes the decrease in northwest short period waves during positive IOD and increase during negative IOD.
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Kumar, Kmalesh, and Seema Malhotra Baxi. "DESERT SOLAR POWER INDIA: A SYSTEMATIC STUDY OF POTENTIAL DEVELOPMENT OF SOLAR POWER IN THE INDIAN DESERT." International Journal of Advanced Research 9, no. 10 (October 31, 2021): 1411–14. http://dx.doi.org/10.21474/ijar01/13700.
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The deserts of Rajasthan have long been known for their spare beauty and their intense sunshine. Now that sun is being turned into a surge of solar power expansion that may one day power not just Rajasthan but a wide swath of India with clean energy. Rajasthan, with its 300 days a year of sunshine and relatively cheap desert land, has set a goal even more ambitious than Indias. In this years state budget, the newly formed state government announced it hoped to install 25,000 megawatts of solar energy in the state within the next five years, and infrastructure to transmit that power to the national grid. Rajasthan is no newcomer to renewable energy. Since the 1990s, the state has been home to a range of wind energy projects, with about 2,800 megawatts of wind capacity now installed, out of an estimated potential capacity of 5,000 megawatts. Altogether wind power in Rajasthan accounts for about 13 percent of Indias wind energy production. But Rajasthans Great Indian Thar Desert, the test site for Indias first underground explosion of a nuclear weapon 15 years ago, may now help make India a solar power as well. The desert set in Rajasthans largest district Jaisalmer, near the border with Pakistan, it is a place of sand dunes and shrub thickets – but also, increasingly, solar installations that could help change the character of Indias energy development. India committed at the U.N. Framework Convention on Climate Change negotiations in Copenhagen in 2009 to reduce its climate-changing emissions, per unit of GDP, by 20 to 25 percent by 2020, compared to 2005 levels. The country is currently the worlds seventh largest emitter of global warming pollution and the fifth biggest producer of emissions from burning fossil fuels. Sixty-eight percent of those emissions from fossil fuel use come from creating energy for the worlds second most populous country, according to Indias energy ministry. Today the country has 2.28 million megawatts of power generating capacity, and about 12.4 percent of that comes from renewable energy. Of the 2,632 megawatts of solar power now installed in India, Rajasthan so far has only 730 megawatts, putting it in second place behind the state of Gujarat, with 916 megawatts, according to Indias Ministry of New and Renewable Energy. But Rajasthan, Indias largest state and 60 percent covered by sunny desert, is now attracting the worlds interest as a solar hotspot. Around 1 lakh (100,000) square kilometers of barren land is available in the northwest arid belt of the state at cheaper rates that could be utilized for large scale solar projects. The government is formulating the policy to harness the enormous solar potential of the region to meet the countrys growing energy requirements. Besides large solar installations, the government is studying the possibility of grid-connected rooftop solar photovoltaic units for households. The Solar Energy Corporation of India estimates that 130 million homes could potentially be equipped with the units, creating 25,000 megawatts of generating capacity. said Alok, Rajasthans Energy Secretary.
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Zheng, Xiao-Tong, Shang-Ping Xie, and Qinyu Liu. "Response of the Indian Ocean Basin Mode and Its Capacitor Effect to Global Warming*." Journal of Climate 24, no. 23 (December 1, 2011): 6146–64. http://dx.doi.org/10.1175/2011jcli4169.1.
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Abstract The development of the Indian Ocean basin (IOB) mode and its change under global warming are investigated using a pair of integrations with the Geophysical Fluid Dynamics Laboratory Climate Model version 2.1 (CM2.1). In the simulation under constant climate forcing, the El Niño–induced warming over the tropical Indian Ocean (TIO) and its capacitor effect on summer northwest Pacific climate are reproduced realistically. In the simulation forced by increased greenhouse gas concentrations, the IOB mode and its summer capacitor effect are enhanced in persistence following El Niño, even though the ENSO itself weakens in response to global warming. In the prior spring, an antisymmetric pattern of rainfall–wind anomalies and the meridional SST gradient across the equator strengthen via increased wind–evaporation–sea surface temperature (WES) feedback. ENSO decays slightly faster in global warming. During the summer following El Niño decay, the resultant decrease in equatorial Pacific SST strengthens the SST contrast with the enhanced TIO warming, increasing the sea level pressure gradient and intensifying the anomalous anticyclone over the northwest Pacific. The easterly wind anomalies associated with the northwest Pacific anticyclone in turn sustain the SST warming over the north Indian Ocean and South China Sea. Thus, the increased TIO capacitor effect is due to enhanced air–sea interaction over the TIO and with the western Pacific. The implications for the observed intensification of the IOB mode and its capacitor effect after the 1970s are discussed.
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Sandeep, S., R. S. Ajayamohan, William R. Boos, T. P. Sabin, and V. Praveen. "Decline and poleward shift in Indian summer monsoon synoptic activity in a warming climate." Proceedings of the National Academy of Sciences 115, no. 11 (February 26, 2018): 2681–86. http://dx.doi.org/10.1073/pnas.1709031115.
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Cyclonic atmospheric vortices of varying intensity, collectively known as low-pressure systems (LPS), travel northwest across central India and produce more than half of the precipitation received by that fertile region and its ∼600 million inhabitants. Yet, future changes in LPS activity are poorly understood, due in part to inadequate representation of these storms in current climate models. Using a high-resolution atmospheric general circulation model that realistically simulates the genesis distribution of LPS, here we show that Indian monsoon LPS activity declines about 45% by the late 21st century in simulations of a business-as-usual emission scenario. The distribution of LPS genesis shifts poleward as it weakens, with oceanic genesis decreasing by ∼60% and continental genesis increasing by ∼10%; over land the increase in storm counts is accompanied by a shift toward lower storm wind speeds. The weakening and poleward shift of the genesis distribution in a warmer climate are confirmed and attributed, via a statistical model, to the reduction and poleward shift of low-level absolute vorticity over the monsoon region, which in turn are robust features of most coupled model projections. The poleward shift in LPS activity results in an increased frequency of extreme precipitation events over northern India.
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Mehta, Darshan, and S. M. Yadav. "An analysis of rainfall variability and drought over Barmer District of Rajasthan, Northwest India." Water Supply 21, no. 5 (February 22, 2021): 2505–17. http://dx.doi.org/10.2166/ws.2021.053.
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Abstract Climate variability, mainly the annual air temperature and precipitation, have received great attention worldwide. The magnitude of this climate variability changes with variation in location. Rajasthan comes under the arid and semi-arid zone of India in which monsoon is a principal element of water resource. Due to erratic and scanty rainfall in this zone, agriculture is totally dependent on the monsoon. The objective of the present study is to assess the meteorological drought characteristics using Drought Indices Calculator DrinC from the historical rainfall records of the Barmer District of Rajasthan State by employing the criterion of percentage departure (D%), rainfall anomaly index (RAI) and standardized precipitation index (SPI). Trend analysis of seasonal and extreme annual monthly rainfall was carried out for the Barmer District of Rajasthan State using the data period between 1901 and 2002 at the 5% level of significance. Sen's slope estimator was also applied to identify the trend. Temporal analysis is useful to predict and identify the possible drought severity and its duration in the study region. It also helps in understanding its effect on groundwater recharge and increasing the risk of water shortage. Trend analysis of rainfall over 102 years shows an increasing trend in pre-monsoon, post-monsoon, southwest monsoon and annual rainfall and a decreasing trend in winter rainfall. Through this study, policy makers and local administrators will be benefitted, which will help them in taking proactive drought relief decisions in the drought-hit regions.
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Nandargi, S. S., S. S. Mahto, and S. Ram. "Changes in Seasonality Index Over Sub-Divisions of India During 1951-2015." Open Atmospheric Science Journal 11, no. 1 (August 9, 2017): 105–20. http://dx.doi.org/10.2174/1874282301711010105.
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Background: The varied topographical features of the Indian region are responsible for variation in distribution of rainfall over different parts of the country. More than 80% of the country’s rainfall is received during the monsoon season. Researchers noted that there is change in distribution of this monsoon rainfall associated with climate change and global warming. This changing pattern in rainfall can be investigated by seasonality index (SI) of rainfall. Such studies are essential to identify the changes in runoff, infiltration, surface and groundwater management, agricultural planning, etc. Method: The variation in seasonality in rainfall over the Indian region is examined using monthly rainfall values for the period 1951 to 2015 of 34 meteorological sub-divisions excluding two Sea Islands. A seasonality index (SI) of a monthly rainfall is computed on monthly, seasonal (June to September) and annual scale. It is observed that seasonality index of rainfall of 34 sub-divisions for all months are in the range 0.37 (Jammu & Kashmir) to 1.56 (Saurashtra Kutch & Diu). Results: The results show that rainfall is markedly seasonal with a long dry season and most rainfall in less than three months. Most of the rainfall occurs in monsoon months. The seasonality index for monsoon season is computed and it varies from 0.19 (Nagaland, Manipur, Mizoram,Tripura) to 0.59 (Saurashtra Kutch & Diu) resulting in rainfall spread throughout the year, but with a definite wetter season. Conclusion: Trends of this index through the 65-year period are identified and indicate that seasonality is increasing in Uttaranchal, Himachal Pradesh, Gujarat Region-Dadra & Nagar Haveli; Saurashtra-Kutch & Diu, Konkan & Goa, Madhya Maharashtra, Marathwada, Chattisgarh, Tamilnadu & Pondicherry. The analysis clearly showed the climate change impact on northwest sub-divisions of the country showing increase in SI values leading to dryness during the monsoon season. The negative trend in SI values was observed in Sub- Himalayan West Bengal, Haryana-Delhi-Chandigarh, Punjab, Jammu & Kashmir, West and east Rajasthan, coastal Andhra Pradesh showing increasing wetness for an already wet months although rainfall occurs in a very short period of just a month or two.
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Kuttippurath, Jayanarayanan, Vikas Kumar Patel, Gopalakrishna Pillai Gopikrishnan, and Hamza Varikoden. "Changes in Air Quality, Meteorology and Energy Consumption during the COVID-19 Lockdown and Unlock Periods in India." Air 1, no. 2 (May 4, 2023): 125–38. http://dx.doi.org/10.3390/air1020010.
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The increasing population and its associated amenities demand innovative devices, infrastructure, methods, plans and policies. Regional climate has a great role in deciding the air quality and energy demand, and therefore, weather and climate have an indisputable role in its consumption and storage. Here, we present the changes in trace gases and associated regional weather in India during lockdown and unlock periods of COVID-19. We observe a reduction of about 30% in sulphur dioxide (SO2) and 10–20% in aerosols in the Indo-Gangetic Plain (IGP), large cities, industrial sites, mining areas and thermal power plants during lockdown as compared to the same period in the previous year and with respect to its climatology. However, a considerable increase in aerosols is found, particularly over IGP during Unlock 1.0 (1–30 June 2020), because of the relaxation of lockdown restrictions. The analyses also show a decrease in temperature by 1–3 °C during lockdown compared to its climatology for the same period, mainly in IGP and Central India, possibly due to the significant reduction in absorbing aerosols such as black carbon and decrease in humidity during the period. The west coast, northwest and central India show reduced wind speed when compared to its previous year and climatological values, suggesting that there was a change in regional weather due to the lockdown. Energy demand in India decreased by about 25–30% during the first phase of lockdown and about 20% during the complete lockdown period. This study thus suggests that the reduction of pollution could also modify local weather, and these results would be useful for drafting policy decisions on air pollution reduction, urban development, the energy sector, agriculture and water resources.
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Hu, Wenfeng, Junqiang Yao, Qing He, and Jing Chen. "Changes in precipitation amounts and extremes across Xinjiang (northwest China) and their connection to climate indices." PeerJ 9 (January 25, 2021): e10792. http://dx.doi.org/10.7717/peerj.10792.
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Xinjiang is a major part of China’s arid region and its water resource is extremely scarcity. The change in precipitation amounts and extremes is of significant importance for the reliable management of regional water resources in this region. Thus, this study explored the spatiotemporal changes in extreme precipitation using the Mann–Kendall (M–K) trend analysis, mutation test, and probability distribution functions, based on the observed daily precipitation data from 89 weather stations in Xinjiang, China during 1961–2018. We also examined the correlations between extreme precipitation and climate indices using the cross-wavelet analysis. The results indicated that the climate in Xinjiang is becoming wetter and the intensity and frequency of extreme precipitation has begun to strengthen, with these trends being more obvious after the 1990s. Extreme precipitation trends displayed spatial heterogeneity in Xinjiang. Extreme precipitation was mainly concentrated in mountainous areas, northern Xinjiang, and western Xinjiang. The significant increasing trend of extreme precipitation was also concentrated in the Tianshan Mountains and in northern Xinjiang. In addition, the climate indices, North Atlantic Oscillation, Atlantic Multidecadal Oscillation, Multivariate ENSO Index and Indian Ocean Dipole Index had obvious relationships with extreme precipitation in Xinjiang. The relationships between the extreme precipitation and climate indices were not clearly positive or negative, with many correlations advanced or delayed in phase. At the same time, extreme precipitation displayed periodic changes, with a frequency of approximately 1–3 or 4–7 years. These periodic changes were more obvious after the 1990s; however, the exact mechanisms involved in this require further study.
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Ahmad, Firoz, Md Meraj Uddin, and Laxmi Goparaju. "An evaluation of vegetation health and the socioeconomic dimension of the vulnerability of Jharkhand state of India in climate change scenarios and their likely impact: a geospatial approach." Environmental & Socio-economic Studies 6, no. 4 (December 1, 2018): 39–47. http://dx.doi.org/10.2478/environ-2018-0026.
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AbstractGeospatial evaluation of various datasets is extremely important because it gives a better comprehension of the past, present and future and can therefore be significantly utilized in effective decision making strategies. This study examined the relationships, using geospatial tools, between various diversified datasets such as land use/land cover (LULC), long term Normalized Difference Vegetation Index (NDVI) based changes, long term forest fire points, poverty percentage, tribal percentage, forest fire hotspots, climate change vulnerability, agricultural vulnerability and future (2030) climate change anomalies (RCP-6) of Jharkhand state, India, for a better understanding and knowledge of its vegetation health, LULC, poverty, tribal population and future climate change impact. The long term NDVI (1982-2006) evaluation revealed negative change trends in seven northwest districts of Jharkhand state, these were: Hazaribag, Ramgarh, Palamu, Lohardaga, Chatra, Garhwa and Latehar. The forests as well as the agriculture of these districts have lost their greenness during this period. The forest fire frequency events were found to be more pronounced in the land use/land cover of “tropical lowland forests, broadleaved, evergreen, <1000 m” category, and were roughly twice the intensity of the “tropical mixed deciduous and dry deciduous forests” category. In the nine districts of Jharkhand it was found that 40 % of the population was living below the poverty line which is around twice the national average. The highest poverty districts, in percentage, were: Garwah (53.93), Palamu (49.24), Latehar (47.99) and Chatra (46.2). The southwest and south of Jharkhand state shows a tribal population density of more than 40%. The climate change vulnerability was found to be highest in the district of Saraikela followed by Pashchim Singhbhum, whereas agricultural vulnerability was found to be highest in the district of Pashchim Singhbhum followed by Saraikela, Garhwa, Simdega, Latehar, Palamu and Lohardaga. The temperature anomalies prediction for the year 2030 shows an increasing trend in temperature with values of 0.8°C to 1°C in the state of Jharkhand. The highest increases were observed in the districts of Pashchim Singhbhum, Simdega and Saraikela. Based on these evaluations we can conclude that a few of the districts of Jharkhand, such as Pashchim Singhbhum, Garhwa, Palamu and Latehar need to be prioritized for development on an urgent basis. The outcomes of this study would certainly guide the policymakers to prepare more robust plans when keeping in mind the future climate change impacts for the prioritization of various districts of Jharkhand which suffer from extreme poverty, diminished livelihood and insignificant agricultural productivity for the betterment of the people of Jharkhand based on their adaptive capacity.
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Meehl, Gerald A., Julie M. Arblaster, and William D. Collins. "Effects of Black Carbon Aerosols on the Indian Monsoon." Journal of Climate 21, no. 12 (June 15, 2008): 2869–82. http://dx.doi.org/10.1175/2007jcli1777.1.
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Abstract A six-member ensemble of twentieth-century simulations with changes to only time-evolving global distributions of black carbon aerosols in a global coupled climate model is analyzed to study the effects of black carbon (BC) aerosols on the Indian monsoon. The BC aerosols act to increase lower-tropospheric heating over South Asia and reduce the amount of solar radiation reaching the surface during the dry season, as noted in previous studies. The increased meridional tropospheric temperature gradient in the premonsoon months of March–April–May (MAM), particularly between the elevated heat source of the Tibetan Plateau and areas to the south, contributes to enhanced precipitation over India in those months. With the onset of the monsoon, the reduced surface temperatures in the Bay of Bengal, Arabian Sea, and over India that extend to the Himalayas act to reduce monsoon rainfall over India itself, with some small increases over the Tibetan Plateau. Precipitation over China generally decreases due to the BC aerosol effects. There is a weakened latitudinal SST gradient resulting from BC aerosols in the model simulations as seen in the observations, and this is present in the multiple-forcings experiments with the Community Climate System Model, version 3 (CCSM3), which includes natural and anthropogenic forcings (including BC aerosols). The BC aerosols and consequent weakened latitudinal SST gradient in those experiments are associated with increased precipitation during MAM in northern India and over the Tibetan Plateau, with some decreased precipitation over southwest India, the Bay of Bengal, Burma, Thailand, and Malaysia, as seen in observations. During the summer monsoon season, the model experiments show that BC aerosols have likely contributed to observed decreasing precipitation trends over parts of India, Bangladesh, Burma, and Thailand. Analysis of single ensemble members from the multiple-forcings experiment suggests that the observed increasing precipitation trends over southern China appear to be associated with natural variability connected to surface temperature changes in the northwest Pacific.
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Butcher, Andrea. "Keeping the Faith: Divine Protection and Flood Prevention in Modern Buddhist Ladakh." Worldviews 17, no. 2 (2013): 103–14. http://dx.doi.org/10.1163/15685357-01702002.
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In August 2010 the Himalayan Region of Ladakh, Northwest India, experienced severe flash-flooding and mudslides, causing widespread death and destruction. The causes cited were climate change, karmic retribution, and the wrath of an agentive sentient landscape. Ladakhis construct, order and maintain the physical and moral universe through religious engagement with this landscape. The Buddhist monastic incumbents—the traditional mediators between the human world and the sentient landscape—explain supernatural retribution as the result of karmic demerit that requires ritual intervention. Social, economic, and material transformations have distorted the proper order, generating a physically and morally unfamiliar landscape. As a result, the mountain deities that act as guardians and protectors of the land below are confused and angry, sending destructive water to show their displeasure. Thus, the locally-contextualized response demonstrates the agency of the mountain gods in establishing a moral universe whereby water can give life and destroy it.
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Hu, Kaiming, Gang Huang, Xiao-Tong Zheng, Shang-Ping Xie, Xia Qu, Yan Du, and Lin Liu. "Interdecadal Variations in ENSO Influences on Northwest Pacific–East Asian Early Summertime Climate Simulated in CMIP5 Models." Journal of Climate 27, no. 15 (July 29, 2014): 5982–98. http://dx.doi.org/10.1175/jcli-d-13-00268.1.
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Abstract The present study investigates interdecadal modulations of the El Niño–Southern Oscillation (ENSO) influence on the climate of the northwest Pacific (NWP) and East Asia (EA) in early boreal summer following a winter ENSO event, based on 19 simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5). In the historical run, 8 out of 19 models capture a realistic relationship between ENSO and NWP early summer climate—an anomalous anticyclone develops over the NWP following a winter El Niño event—and the interdecadal modulations of this correlation. During periods when the association between ENSO and NWP early summer climate is strong, ENSO variance and ENSO-induced anomalies of summer sea surface temperature (SST) and tropospheric temperature over the tropical Indian Ocean (TIO) all strengthen relative to periods when the association is weak. In future projections with representative concentration pathways 4.5 and 8.5, the response of TIO SST, tropospheric temperature, and NWP anomalous anticyclone to ENSO all strengthen regardless of ENSO amplitude change. In a warmer climate, low-level specific humidity response to interannual SST variability strengthens following the Clausius–Clapeyron equation. The resultant intensification of tropospheric temperature response to interannual TIO warming is suggested as the mechanism for the strengthened ENSO effect on NWP–EA summer climate.
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Gilder, Eric, and Dilip K. Pal. "Climate Change – Probable Socio-Economic Systems (SES) Implications And Impacts In The Anthropocene Epoch." International conference KNOWLEDGE-BASED ORGANIZATION 21, no. 2 (June 1, 2015): 308–17. http://dx.doi.org/10.1515/kbo-2015-0052.
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Abstract It is vital for security experts to learn from the historical records of global climate change as to how the human society has been impacted by its consequences in the “new” Anthropocene Epoch. Some of these consequences of global climate change include the perishing of several human settlements in different parts of the globe at different times, e.g., in 1700 B.C., prolonged drought contributed to the demise of Harappan civilization in northwest India. In 1200 B.C., under a similar climatic extremity, the Mycenaean civilization in present-day Greece (as well as the Mill Creek culture of the northwestern part of the present-day US state of Iowa) perished. Why did some societies under such climatic events perish while others survived? Lack of preparedness of one society and its failure to anticipate and adapt to the extreme climatic events might have attributed to their extinction. The authors will also analyze the extinction of one European Norse society in Greenland during the Little Ice Age (about 600 years ago), as compared to the still-surviving Inuit society in the northern segment of Greenland, which faced even harsher climatic conditions during the Little Ice Age than the extinct Norsemen. This is how the adaptability and “expectation of the worst” matter for the survival of a particular community against climatic “black swan” events (Taleb, 2007). Similar impacts in terms of sea-level rise expected by the year 2100 whereby major human populations of many parts of the world are expected to lose their environmental evolutionary “niche” will be discussed. Rising temperature will not only complicate human health issues, but also will it take its toll on the staple food producing agricultural belts in some latitudinal expanse. It will also worsen the living condition of the populace living in areas where climate is marginal. Through the Socio-Economic Systems Model provided by Vadineanu (2001), the authors will next consider the effect of extant policy-making “prisms” responding to climate change (such as the “Club of Rome” versus the “Club for Growth” visions) as concerns the ongoing process of globalization and survival of the nation-state.
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Jiang, Wenping, Gang Huang, Ping Huang, and Kaiming Hu. "Weakening of Northwest Pacific Anticyclone Anomalies during Post–El Niño Summers under Global Warming." Journal of Climate 31, no. 9 (May 2018): 3539–55. http://dx.doi.org/10.1175/jcli-d-17-0613.1.
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The northwest Pacific anticyclone (NWPAC) anomalies during post–El Niño summers are a key predictor of the summer climate in East Asia and the northwestern Pacific (NWP). Understanding how this will change under global warming is crucial to project the changes in the variability of the northwest Pacific summer monsoon. Outputs from 18 selected coupled models from phase 5 of the Coupled Model Intercomparison Project show that the anomalous NWPAC response to El Niño will likely be weakened under global warming, which is attributed to the decreased zonal contrast between the tropical Indian Ocean (TIO) warming and the NWP cooling during post–El Niño summers. Under global warming, the NWPAC anomalies during the El Niño mature winter are weakened because of decreased atmospheric circulation in response to El Niño–Southern Oscillation (ENSO), which leads to the weakening of local air–sea interaction and then decreases the cold NWP SST anomalies. Furthermore, the decreased surface heat flux anomalies, the weakened anticyclone anomalies over the southeastern Indian Ocean, and the slackened anomalous easterlies over the north Indian Ocean weaken the warm TIO SST anomalies. However, the strengthened tropospheric temperature anomalies could enhance the anomalous TIO warming. Although the changes in TIO SST anomalies are indistinctive, the weakening of the SST anomaly gradient between the TIO and the NWP is robust to weaken the NWPAC anomalies during post–El Niño summers. Moreover, the positive feedback between the TIO–NWP SST anomalies and the NWPAC anomalies will enhance the weakening of NWPAC under global warming.
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Sea, Debra S., and Cathy Whitlock. "Postglacial Vegetation and Climate of the Cascade Range, Central Oregon." Quaternary Research 43, no. 3 (May 1995): 370–81. http://dx.doi.org/10.1006/qres.1995.1043.
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AbstractPollen data from two sites provide information on the postglacial vegetation and climate history of the Cascade Range. Indian Prairie in the western Cascade Range was colonized by subalpine forests of Pinus, Picea, and Tsuga and open meadows prior to ca. 12,400 14C yr B.P. The treeline lay 500 to 1000 m below its modern elevation and conditions were cooler than at present. From ca. 12,400 to ca. 9950 14C yr B.P. Abies became important and the forest resembled that presently found at middle elevations in the western Cascade Range. The pollen record implies a rise in treeline and warmer conditions than before. From ca. 10,000 to 4000-4500 14C yr B.P., conditions that were warmer and effectively drier than today led to the establishment of a closed forest composed of Pseudotsuga, Abies, and, at lower elevations, Quercus and Corylus. During this period, Gold Lake Bog in the High Cascades was surrounded by closed forest of Pinus and Abies. The early-Holocene pollen assemblages at both Indian Prairie and Gold Lake Bog lack modern analogues, and it is likely that greater-than-present summer radiation fostered unique climatic conditions and vegetation associations at middle and high elevations. In the late Holocene, beginning ca. 4000-4500 14C yr B.P., cooler and more humid conditions prevailed and the modern vegetation was established. A comparison of these sites with others in the Pacific Northwest suggests that major patterns of vegetational change at individual sites were a response to large-scale changes in the climate system that affected the entire region.
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Singh, Nityanand, and Ashwini Ranade. "The Wet and Dry Spells across India during 1951–2007." Journal of Hydrometeorology 11, no. 1 (February 1, 2010): 26–45. http://dx.doi.org/10.1175/2009jhm1161.1.
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Abstract Characteristics of wet spells (WSs) and intervening dry spells (DSs) are extremely useful for water-related sectors. The information takes on greater significance in the wake of global climate change and climate-change scenario projections. The features of 40 parameters of the rainfall time distribution as well as their extremes have been studied for two wet and dry spells for 19 subregions across India using gridded daily rainfall available on 1° latitude × 1° longitude spatial resolution for the period 1951–2007. In a low-frequency-mode, intra-annual rainfall variation, WS (DS) is identified as a “continuous period with daily rainfall equal to or greater than (less than) daily mean rainfall (DMR) of climatological monsoon period over the area of interest.” The DMR shows significant spatial variation from 2.6 mm day−1 over the extreme southeast peninsula (ESEP) to 20.2 mm day−1 over the southern-central west coast (SCWC). Climatologically, the number of WSs (DSs) decreases from 11 (10) over the extreme south peninsula to 4 (3) over northwestern India as a result of a decrease in tropical and oceanic influences. The total duration of WSs (DSs) decreases from 101 (173) to 45 (29) days, and the duration of individual WS (DS) from 12 (18) to 7 (11) days following similar spatial patterns. Broadly, the total rainfall of wet and dry spells, and rainfall amount and rainfall intensity of actual and extreme wet and dry spells, are high over orographic regions and low over the peninsula, Indo-Gangetic plains, and northwest dry province. The rainfall due to WSs (DSs) contributes ∼68% (∼17%) to the respective annual total. The start of the first wet spell is earlier (19 March) over ESEP and later (22 June) over northwestern India, and the end of the last wet spell occurs in reverse, that is, earlier (12 September) from northwestern India and later (16 December) from ESEP. In recent years/decades, actual and extreme WSs are slightly shorter and their rainfall intensity higher over a majority of the subregions, whereas actual and extreme DSs are slightly (not significantly) longer and their rainfall intensity weaker. There is a tendency for the first WS to start approximately six days earlier across the country and the last WS to end approximately two days earlier, giving rise to longer duration of rainfall activities by approximately four days. However, a spatially coherent, robust, long-term trend (1951–2007) is not seen in any of the 40 WS/DS parameters examined in the present study.
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Xie, Shang-Ping, Yan Du, Gang Huang, Xiao-Tong Zheng, Hiroki Tokinaga, Kaiming Hu, and Qinyu Liu. "Decadal Shift in El Niño Influences on Indo–Western Pacific and East Asian Climate in the 1970s*." Journal of Climate 23, no. 12 (June 15, 2010): 3352–68. http://dx.doi.org/10.1175/2010jcli3429.1.
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Abstract El Niño’s influence on the subtropical northwest (NW) Pacific climate increased after the climate regime shift of the 1970s. This is manifested in well-organized atmospheric anomalies of suppressed convection and a surface anticyclone during the summer (June–August) of the El Niño decay year [JJA(1)], a season when equatorial Pacific sea surface temperature (SST) anomalies have dissipated. In situ observations and ocean–atmospheric reanalyses are used to investigate mechanisms for the interdecadal change. During JJA(1), the influence of the El Niño–Southern Oscillation (ENSO) on the NW Pacific is indirect, being mediated by SST conditions over the tropical Indian Ocean (TIO). The results here show that interdecadal change in this influence is due to changes in the TIO response to ENSO. During the postregime shift epoch, the El Niño teleconnection excites downwelling Rossby waves in the south TIO by anticyclonic wind curls. These Rossby waves propagate slowly westward, causing persistent SST warming over the thermocline ridge in the southwest TIO. The ocean warming induces an antisymmetric wind pattern across the equator, and the anomalous northeasterlies cause the north Indian Ocean to warm through JJA(1) by reducing the southwesterly monsoon winds. The TIO warming excites a warm Kelvin wave in tropospheric temperature, resulting in robust atmospheric anomalies over the NW Pacific that include the surface anticyclone. During the preregime shift epoch, ENSO is significantly weaker in variance and decays earlier than during the recent epoch. Compared to the epoch after the mid-1970s, SST and wind anomalies over the TIO are similar during the developing and mature phases of ENSO but are very weak during the decay phase. Specifically, the southern TIO Rossby waves are weaker, so are the antisymmetric wind pattern and the North Indian Ocean warming during JJA(1). Without the anchor in the TIO warming, atmospheric anomalies over the NW Pacific fail to develop during JJA(1) prior to the mid-1970s. The relationship of the interdecadal change to global warming and implications for the East Asian summer monsoon are discussed.
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Emeis, Kay-Christian, David M. Anderson, Heidi Doose, Dick Kroon, and Detlef Schulz-Bull. "Sea-Surface Temperatures and the History of Monsoon Upwelling in the Northwest Arabian Sea during the Last 500,000 Years." Quaternary Research 43, no. 3 (May 1995): 355–61. http://dx.doi.org/10.1006/qres.1995.1041.
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AbstractArabian Sea sediments record changes in the upwelling system off Arabia, which is driven by the monsoon circulation system over the NW Indian Ocean. In accordance with climate models, and differing from other large upwelling areas of the tropical ocean, a 500,000-yr record of productivity at ODP Site 723 shows consistently stronger upwelling during interglaciations than during glaciations. Sea-surface temperatures (SSTs) reconstructed from the alkenone unsaturation index (UK′37) are high (up to 27°C) during interglaciations and low (22-24°C) during glaciations, indicating a glacial-interglacial temperature change of >3°C in spite of the dampening effect of enhanced or weakened upwelling. The increased productivity is attributed to stronger monsoon winds during interglacial times relative to glacial times, whereas the difference in SSTs must be unrelated to upwelling and to the summer monsoon intensity. The winter (NE) monsoon was more effective in cooling the Arabian Sea during glaciations then it is now.
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Kaskaoutis, D. G., S. K. Kharol, P. R. Sinha, R. P. Singh, K. V. S. Badarinath, W. Mehdi, and M. Sharma. "Contrasting aerosol trends over South Asia during the last decade based on MODIS observations." Atmospheric Measurement Techniques Discussions 4, no. 4 (August 16, 2011): 5275–323. http://dx.doi.org/10.5194/amtd-4-5275-2011.
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Abstract. Atmospheric aerosols over south Asia constitute a major environmental and climate issue. Thus, extensive land and cruise campaigns have been conducted over the area focusing on investigating the aerosol properties and climate implications. Except from the ground-based instrumentation, several studies dealt with analyzing the aerosol properties from space, focusing mainly on the spatial distribution of the aerosol optical depth (AOD) and possible feedbacks of aerosols on the monsoon system. However, except from some works using ground-based instrumentation or satellite observations over a specific region, there is lack of studies dealing with monitoring of the aerosol trend over south Asia. The present work analyzes the variations and trends in aerosol load over south Asia using Terra-MODIS AOD550 data in the period 2000–2009. Overall, an increasing trend of 10.17 % in AOD is found over whole south Asia, which exhibits large spatio-temporal variation. More specifically, the AOD550 increasing trend is more pronounced in winter, and especially over northern India. The present study shows an evidence of a decreasing AOD550 trend over the densely-populated Indo-Gangetic Plains (IGP) during the period April–September, which has never been reported before. This decreasing trend is not statistically significant and leads to an AOD change of −0.01 per year in June, when the dust activity is at its maximum. The AOD decrease seems to be attributed to weakness of dust activity in the northwest of India, closely associated with expansion of the vegetated areas and increase in precipitation over the Thar desert. Similarly, GOCART simulations over south Asia show a pronounced decreasing trend in dust AOD in accordance with MODIS. However, much more analysis and longer dataset are required for establishing this evidence.
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Huang, Gang, Kaiming Hu, and Shang-Ping Xie. "Strengthening of Tropical Indian Ocean Teleconnection to the Northwest Pacific since the Mid-1970s: An Atmospheric GCM Study*." Journal of Climate 23, no. 19 (October 1, 2010): 5294–304. http://dx.doi.org/10.1175/2010jcli3577.1.
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Abstract The correlation of northwest (NW) Pacific climate anomalies during summer with El Niño–Southern Oscillation (ENSO) in the preceding winter strengthens in the mid-1970s and remains high. This study investigates the hypothesis that the tropical Indian Ocean (TIO) response to ENSO is key to this interdecadal change, using a 21-member ensemble simulation with the Community Atmosphere Model, version 3 (CAM3) forced by the observed history of sea surface temperature (SST) for 1950–2000. In the model hindcast, the TIO influence on the summer NW Pacific strengthens in the mid-1970s, and the strengthened TIO teleconnection coincides with an intensification of summer SST variability over the TIO. This result is corroborated by the fact the model’s skills in simulating NW Pacific climate anomalies during summer increase after the 1970s shift. During late spring to early summer, El Niño–induced TIO warming decays rapidly for the epoch prior to the 1970s shift but grows and persists through summer for the epoch occurring after it. This difference in the evolution of the TIO warming determines the strength of the TIO teleconnection to the NW Pacific in the subsequent summer. An antisymmetric wind pattern develops in spring across the equator over the TIO, and the associated northeasterly anomalies aid the summer warming over the north Indian Ocean by opposing the prevailing southwest monsoon. In the model, this antisymmetric spring wind pattern is well developed after but absent before the 1970s shift.
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Aryal, Sugam, Narayan Prasad Gaire, Nawa Raj Pokhrel, Prabina Rana, Basant Sharma, Deepak Kumar Kharal, Buddi Sagar Poudel, et al. "Spring Season in Western Nepal Himalaya is not yet Warming: A 400-Year Temperature Reconstruction Based on Tree-Ring Widths of Himalayan Hemlock (Tsuga dumosa)." Atmosphere 11, no. 2 (January 24, 2020): 132. http://dx.doi.org/10.3390/atmos11020132.
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The Himalayan region has already witnessed profound climate changes detectable in the cryosphere and the hydrological cycle, already resulting in drastic socio-economic impacts. We developed a 619-yea-long tree-ring-width chronology from the central Nepal Himalaya, spanning the period 1399–2017 CE. However, due to low replication of the early part of the chronology, only the section after 1600 CE was used for climate reconstruction. Proxy climate relationships indicate that temperature conditions during spring (March–May) are the main forcing factor for tree growth of Tsuga dumosa at the study site. We developed a robust climate reconstruction model and reconstructed spring temperatures for the period 1600–2017 CE. Our reconstruction showed cooler conditions during 1658–1681 CE, 1705–1722 CE, 1753–1773 CE, 1796–1874 CE, 1900–1936 CE, and 1973 CE. Periods with comparably warmer conditions occurred in 1600–1625 CE, 1633–1657 CE, 1682–1704 CE, 1740–1752 CE, 1779–1795 CE, 1936–1945 CE, 1956–1972 CE, and at the beginning of the 21st century. Tropical volcanic eruptions showed only a sporadic impact on the reconstructed temperature. Also, no consistent temperature trend was evident since 1600 CE. Our temperature reconstruction showed positive teleconnections with March–May averaged gridded temperature data for far west Nepal and adjacent areas in Northwest India and on the Southwest Tibetan plateau. We found spectral periodicities of 2.75–4 and 40–65 years frequencies in our temperature reconstruction, indicating that past climate variability in central Nepal might have been influenced by large-scale climate modes, like the Atlantic Multi-decadal Oscillation, the North Atlantic Oscillation, and the El Niño-Southern Oscillation.
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Zou, Fang, Robert Tenzer, and Shuanggen Jin. "Water Storage Variations in Tibet from GRACE, ICESat, and Hydrological Data." Remote Sensing 11, no. 9 (May 9, 2019): 1103. http://dx.doi.org/10.3390/rs11091103.
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The monitoring of water storage variations is essential not only for the management of water resources, but also for a better understanding of the impact of climate change on hydrological cycle, particularly in Tibet. In this study, we estimated and analyzed changes of the total water budget on the Tibetan Plateau from the Gravity Recovery And Climate Experiment (GRACE) satellite mission over 15 years prior to 2017. To suppress overall leakage effect of GRACE monthly solutions in Tibet, we applied a forward modeling technique to reconstruct hydrological signals from GRACE data. The results reveal a considerable decrease in the total water budget at an average annual rate of −6.22 ± 1.74 Gt during the period from August 2002 to December 2016. In addition to the secular trend, seasonal variations controlled mainly by annual changes in precipitation were detected, with maxima in September and minima in December. A rising temperature on the plateau is likely a principal factor causing a continuous decline of the total water budget attributed to increase melting of mountain glaciers, permafrost, and snow cover. We also demonstrate that a substantial decrease in the total water budget due to melting of mountain glaciers was partially moderated by the increasing water storage of lakes. This is evident from results of ICESat data for selected major lakes and glaciers. The ICESat results confirm a substantial retreat of mountain glaciers and an increasing trend of major lakes. An increasing volume of lakes is mainly due to an inflow of the meltwater from glaciers and precipitation. Our estimates of the total water budget on the Tibetan Plateau are affected by a hydrological signal from neighboring regions. Probably the most significant are aliasing signals due to ground water depletion in Northwest India and decreasing precipitation in the Eastern Himalayas. Nevertheless, an integral downtrend in the total water budget on the Tibetan Plateau caused by melting of glaciers prevails over the investigated period.
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Renssen, Hans. "Climate model experiments on the 4.2 ka event: The impact of tropical sea-surface temperature anomalies and desertification." Holocene 32, no. 5 (February 4, 2022): 378–89. http://dx.doi.org/10.1177/09596836221074031.
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The 4.2 ka event is one of the most prominent climate events of the Holocene. In this study, several climate model experiments were performed to investigate its causal mechanism. The focus in these experiments was on the impact of anomalies in sea surface temperatures (SSTs) associated with enhanced El Nino activity, as this has been proposed as an important driver for the event. Six different SST anomaly scenarios were considered, covering the tropical sectors of the Pacific, Indian, and Atlantic Oceans. In addition, the possible impact of desertification in Northern Africa and Arabia was taken into account. The model results were evaluated against the global humidity anomaly signature for the 4.2 ka event as provided by proxy-based reconstructions from 129 different sites. It is found that a scenario with desertification and warm Pacific SSTs and cold Atlantic SSTs provides the best match with these proxies. This experiment produces significant decreases in precipitation in South Asia, West and East Africa, and increases in South America and northwest North America. These results are partly forced by the strong increase in albedo in North Africa and Arabia, leading to regional cooling and more stable atmospheric conditions, and partly by enhanced atmospheric moisture transport to South America related to an enhanced land-sea thermal contrast. Based on these results, it is proposed that the 4.2 ka event was caused by tropical SST anomalies, leading to drying in North Africa, assisted by ongoing desertification in Northern Africa and Arabia.
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Lin, Zhongda. "The South Atlantic–South Indian Ocean Pattern: a Zonally Oriented Teleconnection along the Southern Hemisphere Westerly Jet in Austral Summer." Atmosphere 10, no. 5 (May 9, 2019): 259. http://dx.doi.org/10.3390/atmos10050259.
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Extratropical teleconnections significantly affect the climate in subtropical and mid-latitude regions. Understanding the variability of atmospheric teleconnection in the Southern Hemisphere, however, is still limited in contrast with the well-documented counterpart in the Northern Hemisphere. This study investigates the interannual variability of mid-latitude circulation in the Southern Hemisphere in austral summer based on the ERA-Interim reanalysis dataset during 1980–2016. A stationary mid-latitude teleconnection is revealed along the strong Southern Hemisphere westerly jet over the South Atlantic and South Indian Ocean (SAIO). The zonally oriented SAIO pattern represents the first EOF mode of interannual variability of meridional winds at 200 hPa over the region, with a vertical barotropic structure and a zonal wavenumber of 4. It significantly modulates interannual climate variations in the subtropical Southern Hemisphere in austral summer, especially the opposite change in rainfall and surface air temperature between Northwest and Southeast Australia. The SAIO pattern can be efficiently triggered by divergences over mid-latitude South America and the southwest South Atlantic, near the entrance of the westerly jet, which is probably related to the zonal shift of the South Atlantic Convergence Zone. The triggered wave train is then trapped within the Southern Hemisphere westerly jet waveguide and propagates eastward until it diverts northeastward towards Australia at the jet exit, in addition to portion of which curving equatorward at approximately 50° E towards the southwest Indian Ocean.
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SINGH, O. P., K. RUPA KUMAR, P. K. MISHRA, K. KRISHNA KUMAR, and S. K. PATWARDHAN. "Simulation of characteristic features of Asian summer monsoon using a regional climate model." MAUSAM 57, no. 2 (November 25, 2021): 221–30. http://dx.doi.org/10.54302/mausam.v57i2.469.
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Lkkj & bl 'kks/k&i= esa HkweaMyh; tyok;q ifjorZu ds ifj.kkeLo:i 'krkCnh ds e/; ¼2041&60½ ds nkSjku ,f’k;kbZ xzh"edkyhu ekulwu ds fof’k"V y{k.kksa dk iwokZuqeku djus ds mÌs’; ls vuqdj.k iz;ksxksa ds ifj.kke izLrqr fd, x, gSaA blds fy, gSMys tyok;q iwokZuqeku vkSj vuqla/kku dsUnz] ;w- ds- dk {ks=h; tyok;q ekWMy gSM vkj- ,e- 2 dk mi;ksx fd;k x;k gSA ,f’k;kbZ {ks= ds fy, 20 o"kksZa dh vof/k ds nks vuqdj.k iz;ksx fd, x, gSa uker% igyk] 1990 Lrjksa ds vuq:i xzhu gkml xSl lkanz.k dh fu/kkZfjr ek=k] ftls dUVªksy ¼lh- Vh- ,y-½ iz;ksx dgk x;k gS vkSj nwljk 1990 ls ysdj 2041&60 rd ds fy, xzhu gkml xSl lkanz.k ds okf"kZd feJ.k esa 1 izfr’kr dh o`f) lesr ftls vkxs xzhu gkml xSl ¼th- ,p- th-½ iz;ksx dgk x;k gSA xzhu gkml xSl lkanz.k esa okf"kZd feJ.k esa 1 izfr’kr dh o`f) tyok;q ifjorZu ds var% ljdkjh iSuy vkbZ- ih- lh- lh- }kjk rS;kj dh xbZ ;kstuk ls yh xbZ gSA
bu iz;ksxksa ls 'krkCnh ds e/; ds nkSjku ,f’k;kbZ xzh"edkyhu ekulwu esa ik, tkus okys fof’k"V y{k.kksa esa gksus okys dqN ifjorZuksa dk irk pyk gS ftudk c<+s gq, ekuotfur mRltZdksa ds dkj.k gksuk LokHkkfor gSA lewph ekulwu _rq ds nkSjku Hkkjrh; {ks= ij fuEu {kksHk eaMy ¼850 gSDVkikLdy½ esa ekulwu nzks.kh ¼,e- Vh- ½ dk mRrj dh vksj lkekU; :i ls c<+uk lcls vf/kd egRoiw.kZ ifjorZu izrhr gksrk gSA vuqdj.k ifj.kkeksa ls ekulwu _rq ds nkSjku vjc lkxj esa leqnz Lrj nkc ¼,l- ,y- ih-½ esa yxHkx 1&2 gS- ik- dh o`f) dk irk pyk gS ftlds ifj.kkeLo:i fuEu {kksHk eaMy esa vlkekU; izfrpØokr gksrs gSaA bldk vFkZ ;g gqvk fd fuEu Lrjh; tsV ¼,y- ,y- ts-½ vkSj vjc lkxj esa ekulwu dh /kkjk det+ksj iM+ tkrh gSA
;g ekWMy m".krj leqnz lrg dh fLFkfr;ksa esa fgan egklkxj ds mRrj esa ekulwuh pØokrh; fo{kksHkksa dh vko`fr esa deh dks vuqdfjr djrk gS tks gky gh ds n’kdksa esa ekulwu ds vonkcksa dh vko`fr esa deh dh izo`fr;ksa ds vuq:i ikbZ xbZ gSA
bu iz;ksxksa ls ;g irk pyrk gS fd ikfdLrku vkSj mlds lehiorhZ mRrjh if’peh Hkkjr ds Åij Å"ek fuEunkc rhoz gks ldrk gS vkSj ekulwu _rq ds nkSjku FkksM+k iwoZ dh vksj c<+ ldrh gSA ;g ekWMy] Hkkjrh; leqnz ds nf{k.kh Hkkxksa esa 8° & 10° m- ds chp 100 gS- ik- ¼Vh- bZ- ts- dksj dk Lrj½ ij fo’ks"kdj ekulwu ds iwokZ)Z ds nkSjku m".kdfVca/kh; iwokZfHkeq[kh tsV¼Vh- bZ- ts-½ dks izHkkfor djrk gSA
The paper presents the results of simulation experiments aimed at predicting the characteristic features of Asian Summer Monsoon during the middle of the century (2041-60) resulting from global climate change. The model used is HadRM2 regional climate model of the Hadley Centre for Climate Prediction and Research, UK. Two simulation experiments of 20 years length have been performed for the Asian domain, namely, one with a fixed amount of greenhouse gas concentration corresponding to 1990 levels called the 'control' (CTL) experiment and the other with the annual compound increase of 1 % in the greenhouse gas concentration for 2041-60 from 1990 onwards called the 'greenhouse gas' (GHG) experiment. The annual compound increment of 1 %, in the greenhouse gas concentration has been adopted from the projection given by the Intergovernmental Panel for Climate Change (IPCC).
The experiments have brought out some of the changes in the characteristic features of mid-century Asian summer monsoons that are expected to occur due to increased anthropogenic emissions. The most significant change seems to be a general northward shift of the monsoon trough (MT) in the lower troposphere (850 hPa) throughout the monsoon season over the Indian region. The simulation results have shown an increase of about 1-2 hPa in the sea level pressure (SLP) over the Arabian Sea during the monsoon resulting in an anomalous anticyclone over there in the lower troposphere. This would mean the weakening of Low Level Jet (LLJ) and the Arabian sea branch of the monsoon current.
The model has simulated a decrease in the frequency of the monsoonal cyclonic disturbances over the north Indian Ocean under the warmer sea surface conditions which conforms to the observed decreasing trends in the frequency of monsoon depressions in recent decades.
The experiments have shown that the Heat Low over Pakistan and adjoining northwest India, may intensify and shift slightly eastward during the monsoon. The model has simulated the strengthening of Tropical Easterly Jet (TEJ) at 100 hPa (the location of TEJ core ) over the southern parts of Indian sea between 8° - 10° N, especially during the first half of the monsoon season.
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Joswiak, D. R., T. Yao, G. Wu, B. Xu, and W. Zheng. "A 70-yr record of oxygen-18 variability in an ice core from the Tanggula Mountains, central Tibetan Plateau." Climate of the Past 6, no. 2 (April 8, 2010): 219–27. http://dx.doi.org/10.5194/cp-6-219-2010.
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Abstract. A 33 m ice core was retrieved from the Tanggula Mts, central Tibetan Plateau at 5743 m a.s.l. in August 2005. Annual average δ18O values were determined for the upper 17 m depth (14.6 m w.eq.), representing the time series since the mid-1930s. Data are compared to previous results of an ice core from Mt. Geladaindong, 100 km to the northwest, for the period 1935–2003. During the time 1935–1960, δ18O values differed by 2–3‰ between the two ice cores, with generally lower ratios preserved in the Tanggula 2005 core. Differences in interannual variability and overall average ratios between the two study locations highlight the spatially variable climate controls on ice core isotope ratios within the boundary of monsoon- and westerly-impacted regions of the central Tibetan Plateau. Average annual net accumulation was 261 mm w.eq. for the period 1935–2004. The overall average δ18O value was −13.2‰ and exhibited a statistically significant increase from the 1935–1969 average (−13.7‰) to the 1970–2004 average (−12.6‰). Despite the observed increase in isotope ratios, isotopic temperature dependence was not evident, based on comparison with long-term data from meteorological stations to the north and southwest of the study location. Lack of correlation between average δ18O values and temperature is likely due to monsoon influence, which results in relatively greater isotopic depletion of moisture during the warm season. Evidence of monsoon impacts on precipitation in the central Tibetan Plateau has been previously documented, and statistically significant negative correlation (r=−0.37, p<0.01) between the annual average ice core δ18O values and North India monsoon rainfall was observed for the period 1935–2004. Although the δ18O data agree well with the monsoon rainfall amount, no significant correlation was observed between the core accumulation and the monsoon rainfall amount. Previous model and observational results suggest monsoon impact on δ18O in precipitation may extend beyond the immediate extent of heavy monsoon rainfall, reaching the central Tibetan Plateau. These results provide evidence that the δ18O variability at this study location may be sensitive to southern monsoon intensity.
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Riley, Collin, Summer Rupper, James W. Steenburgh, Courtenay Strong, Adam K. Kochanski, and Savanna Wolvin. "Characteristics of Historical Precipitation in High Mountain Asia Based on a 15-Year High Resolution Dynamical Downscaling." Atmosphere 12, no. 3 (March 8, 2021): 355. http://dx.doi.org/10.3390/atmos12030355.
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The mountains of High Mountain Asia serve as an important source of water for roughly one billion people living downstream. This research uses 15 years of dynamically downscaled precipitation produced by the Weather Research and Forecasting (WRF) model to delineate contrasts in precipitation characteristics and events between regions dominated by the Indian Summer Monsoon (ISM) versus westerly disturbances during the cool season (December to March). Cluster analysis reveals a more complex spatial pattern than indicated by some previous studies and illustrates the increasing importance of westerly disturbances at higher elevations. Although prior research suggests that a small number of westerly disturbances dominate precipitation in the western Himalaya and Karakoram, the WRF-downscaled precipitation is less dominated by infrequent large events. Integrated vapor transport (IVT) and precipitation are tightly coupled in both regions during the cool season, with precipitation maximizing for IVT from the south-southwest over the Karakoram and southeast-southwest over the western Himalaya. During the ISM, Karakoram precipitation is not strongly related to IVT direction, whereas over the western Himalaya, primary and secondary precipitation maxima occur for flow from the west-southwest and northwest, respectively. These differences in the drivers and timing of precipitation have implications for hydrology, glacier mass balance, snow accumulation, and their sensitivity to climate variability and change.
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Hoyos, Carlos D., and Peter J. Webster. "The Role of Intraseasonal Variability in the Nature of Asian Monsoon Precipitation." Journal of Climate 20, no. 17 (September 1, 2007): 4402–24. http://dx.doi.org/10.1175/jcli4252.1.
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Abstract The structure of the mean precipitation of the south Asian monsoon is spatially complex. Embedded in a broad precipitation maximum extending eastward from 70°E to the northwest tropical Pacific Ocean are strong local maxima to the west of the Western Ghats mountain range of India, in Cambodia extending into the eastern China Sea, and over the eastern tropical Indian Ocean and the Bay of Bengal (BoB), where the strongest large-scale global maximum in precipitation is located. In general, the maximum precipitation occurs over the oceans and not over the land regions. Distinct temporal variability also exists with time scales ranging from days to decades. Neither the spatial nor temporal variability of the monsoon can be explained simply as the response to the cross-equatorial pressure gradient force between the continental regions of Asia and the oceans of the Southern Hemisphere, as suggested in classical descriptions of the monsoon. Monthly (1979–2005) and daily (1997–present) rainfall estimates from the Global Precipitation Climatology Project (GPCP), 3-hourly (1998–present) rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM) microwave imager (TMI) estimates of sea surface temperature (SST), reanalysis products, and satellite-determined outgoing longwave radiation (OLR) data were used as the basis of a detailed diagnostic study to explore the physical basis of the spatial and temporal nature of monsoon precipitation. Propagation characteristics of the monsoon intraseasonal oscillations (MISOs) and biweekly signals from the South China Sea, coupled with local and regional effects of orography and land–atmosphere feedbacks are found to modulate and determine the locations of the mean precipitation patterns. Long-term variability is found to be associated with remote climate forcing from phenomena such as El Niño–Southern Oscillation (ENSO), but with an impact that changes interdecadally, producing incoherent responses of regional rainfall. A proportion of the interannual modulation of monsoon rainfall is found to be the direct result of the cumulative effect of rainfall variability on intraseasonal (25–80 day) time scales over the Indian Ocean. MISOs are shown to be the main modulator of weather events and encompass most synoptic activity. Composite analysis shows that the cyclonic system associated with the northward propagation of a MISO event from the equatorial Indian Ocean tends to drive moist air toward the Burma mountain range and, in so doing, enhances rainfall considerably in the northeast corner of the bay, explaining much of the observed summer maximum oriented parallel to the mountains. Similar interplay occurs to the west of the Ghats. While orography does not seem to play a defining role in MISO evolution in any part of the basin, it directly influences the cumulative MISO-associated rainfall, thus defining the observed mean seasonal pattern. This is an important conclusion since it suggests that in order for the climate models to reproduce the observed seasonal monsoon rainfall structure, MISO activity needs to be well simulated and sharp mountain ranges well represented.
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SINGH, B. B., R. N. SHARMA, J. P. S. GILL, R. S. AULAKH, and S. BANGAH. "Climate change, zoonoses and India." Revue Scientifique et Technique de l'OIE 30, no. 3 (December 1, 2011): 779–88. http://dx.doi.org/10.20506/rst.30.3.2073.
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Saryal, Rajnish. "Climate Change Policy of India." South Asia Research 38, no. 1 (January 22, 2018): 1–19. http://dx.doi.org/10.1177/0262728017745385.
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Since the 1970s, and especially following the 1992 Rio Earth Summit, climate change has become an area of high politics, engaging the whole world at the international and diplomatic level. What matters, though, is how this translates into tangible policies at national and local levels, and how these different scales interact. Highlighting India’s unique position in international climate negotiations, this article first scrutinises various official statements and documents of the Government of India (GOI) on climate change and puts them into an analytical framework that demonstrates continuities, but also significant recent shifts. Investigating the reasons for such modifying trends and examining their consequences, the article then suggests that partly owing to recent changes in global and (geo)political contexts, but also due to an Indian re-thinking of responsibility for addressing global climate change, there is a significant new development. This seems to augur a South Asian ‘silent revolution’ in green technologies, a prudent, economically and ecologically beneficial step, not only for India but possibly a sustainable global model.
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Brubaker, Michael, James Berner, Raj Chavan, and John Warren. "Climate change and health effects in Northwest Alaska." Global Health Action 4, no. 1 (October 18, 2011): 8445. http://dx.doi.org/10.3402/gha.v4i0.8445.
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White, P. Troy, Kattlyn J. Wolf, Jodi L. Johnson-Maynard, Jonathan J. Velez, and Sanford D. Eigenbrode. "Secondary Climate Change Education in the Pacific Northwest." Natural Sciences Education 43, no. 1 (May 13, 2014): 85–93. http://dx.doi.org/10.4195/nse2014.01.0001.
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Shi, Yafeng, Yongping Shen, Ersi Kang, Dongliang Li, Yongjian Ding, Guowei Zhang, and Ruji Hu. "Recent and Future Climate Change in Northwest China." Climatic Change 80, no. 3-4 (August 10, 2006): 379–93. http://dx.doi.org/10.1007/s10584-006-9121-7.
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Markoff, Matthew S., and Alison C. Cullen. "Impact of climate change on Pacific Northwest hydropower." Climatic Change 87, no. 3-4 (July 25, 2007): 451–69. http://dx.doi.org/10.1007/s10584-007-9306-8.
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Yao, Xuyang, Mingjun Zhang, Yu Zhang, Hanyu Xiao, and Jiaxin Wang. "Research on Evaluation of Climate Comfort in Northwest China under Climate Change." Sustainability 13, no. 18 (September 9, 2021): 10111. http://dx.doi.org/10.3390/su131810111.
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Based on the monthly observation data of major surface meteorological observatories in Northwest China from 1960 to 2019, this paper uses the temperature and humidity index (THI), wind efficiency index (WEI), and clothing index (ICL) to construct a comprehensive climate comfort index evaluation model. This model was used to quantitatively evaluate the change characteristics of climate comfort in Northwest China against the background of climate warming. The results show that the overall climate comfort index in Northwest China is on the rise. In terms of space, an increase in the climate comfort index means an increase in the comfort zone, with the largest increase in the southeastern part of Gansu Province and the southern part of Shaanxi Province. The trend of change is that the increase in the north is greater than that in the south, and the higher the latitude, the greater the change. The space range of the comfort zone and the sub-comfort zone is generally expanding, and the climate is gradually becoming more comfortable. In terms of time, an increase in the climate comfort index means an increase in the climate comfort period, and the annual comfort index shows an increasing trend. The comfort period is mostly distributed in summer, with the most suitable cities in May and September, followed by June.