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Yaning Chen - One of the best experts on this subject based on the ideXlab platform.
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potential risks and challenges of climate change in the Arid Region of northwestern china
Regional Sustainability, 2020Co-Authors: Yaning Chen, Gonghuan Fang, Xueqi Zhang, Fei Wang, Jingxiu Qin, Fan SunAbstract:Abstract In the Arid Region of northwestern China (ARNC), water resources are the most critical factor restricting socioeconomic development and influencing the stability of the area’s ecological systems. The Region’s complex water system and unique hydrological cycle show distinctive characteristics. Moreover, the intensified hydrological cycle and extreme climatic and hydrological events resulting from global warming have led to increased uncertainty around water resources as well as heightened conflict between water supply and water demand. All of these factors are exerting growing pressures on the socioeconomic development and vulnerable ecological environment in the Region. This research evaluates the impacts of climate change on water resources, hydrological processes, agricultural system, and desert ecosystems in the ARNC, and addresses some associated risks and challenges specific to this area. The temperature is rising at a rate of 0.31 °C per decade during 1961–2017 and hydrological processes are being significantly influenced by changes in glaciers, snow cover, and precipitation form, especially in the rivers recharged primarily by melt water. Ecosystems are also largely influenced by climate change, with the Normalized Difference Vegetation Index (NDVI) of natural vegetation exhibited an increasing trend prior to 1998, and then reversed in Xinjiang while the Hexi Corridor of Gansu showed the opposite trends. Furthermore, the desert-oasis transition zone showed a reduction in area due to the warming trend and the recent rapid expansion of irrigated area. Both the warming and intensified drought are threatening agriculture security. The present study could shed light on sustainable development in this Region under climate change and provides scientific basis to the construction of the “Silk Road Economic Belt”.
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evaluation of multiple gridded precipitation datasets for the Arid Region of northwestern china
Atmospheric Research, 2020Co-Authors: Yaning Chen, Junqiang Yao, Yong Zhao, Xuefeng Guan, Lianmei YangAbstract:Abstract Gridded precipitation datasets for the Arid Region of northwestern China (ARNC) are thought to have large discrepancies. This study systematically evaluated the performance of multiple datasets for the ARNC over the period 1980–2014 using the observed gridded precipitation dataset (OBS) from the China Meteorological Administration (CMA). The various datasets include two National Center for Environmental Prediction (NCEP) reanalyses (NCEP-1 and NCEP-2), two Climate Prediction Center (CPC) Merged Analyses of Precipitation (CMAP-1 and CMAP-2), the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA-Interim), the Global Precipitation Climatology Project (GPCP), the Climatic Research Unit, University of East Anglia, UK (CRU), and the second Modern-Era Retrospective Analysis for Research and Application system (MERRA-2). The results show that all the multiple datasets reasonably reproduce the climatology, seasonality, interannual variability, and spatiotemporal patterns of ARNC precipitation, but there are discrepancies in the long-term trends. MERRA-2 and CMAP-2 best capture the spatial distributions and inter-annual variability of mean annual precipitation (MAP). CRU best reproduced the seasonality and temporal variability of MAP. However, ERA-Interim and NCEP overestimated the precipitation amount in mountainous Regions, and MERRA-2 underestimated precipitation in almost all seasons. Empirical orthogonal function (EOF) analysis indicated that GPCP and CMAP-2 better described both the spatial modes and principal components of the first two EOF patterns. The systematic evaluation in this study indicated that, overall, most of the satellite-merged datasets (GPCP, MERRA-2, and CMAP-2) perform better than gauge-based and reanalysis datasets alone. This study demonstrates that a systematic evaluation of the differences between multiple datasets is critical for reducing discrepancies.
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hydrological and water cycle processes of inland river basins in the Arid Region of northwest china
Journal of Arid Land, 2019Co-Authors: Yaning Chen, L I Baofu, Gonghuan FangAbstract:The increasing shortage in water resources is a key factor affecting sustainable socio-economic development in the Arid Region of Northwest China (ARNC). Water shortages also affect the stability of the Region’s oasis ecosystem. This paper summarizes the hydrological processes and water cycle of inland river basins in the ARNC, focusing on the following aspects: the spatial-temporal features of water resources (including air water vapor resources, runoff, and glacial meltwater) and their driving forces; the characteristics of streamflow composition in the inland river basins; the characteristics and main controlling factors of baseflow in the inland rivers; and anticipated future changes in hydrological processes and water resources. The results indicate that: (1) although the runoff in most inland rivers in the ARNC showed a significant increasing trend, both the glaciated area and glacial ice reserves have been reduced in the mountains; (2) snow melt and glacier melt are extremely important hydrological processes in the ARNC, especially in the Kunlun and Tianshan mountains; (3) baseflow in the inland rivers of the ARNC is the result of climate change and human activities, with the main driving factors being the reduction in forest area and the over-exploitation and utilization of groundwater in the river basins; and (4) the contradictions among water resources, ecology and economy will further increase in the future. The findings of this study might also help strengthen the ecological, economic and social sustainable development in the study Region.
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linear trend and abrupt changes of climate indices in the Arid Region of northwestern china
Atmospheric Research, 2017Co-Authors: Huaijun Wang, Yaning Chen, Zhengwei YeAbstract:Abstract In recent years, climate extreme events have caused increasing direct economic and social losses in the Arid Region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with − 1.89%days/decade, 0.65 °C/decade and − 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual Regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the Regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices, which will have serious impacts on water resources and ecological environment in the Arid Region of China.
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comparison of three drought indices and their evolutionary characteristics in the Arid Region of northwestern china
Atmospheric Science Letters, 2017Co-Authors: Huaijun Wang, Yingping Pan, Yaning ChenAbstract:Drought evolutions in the Arid Region of northwestern China from 1960 to 2010 were analyzed based on the standardized precipitation index (SPI), the standardized precipitation-evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI). All three forms of drought indices were significantly correlated with each other. No statistically significant differences were found for the severity of drought, as assessed by both the SPI and SPEI. The SC-PDSI was generally an index representing water deficits at a medium period. For the entire geographical area of study, wet conditions dominated during 1987–2010, whereas persistent drought conditions occurred from 1960 to 1986.
Huaijun Wang - One of the best experts on this subject based on the ideXlab platform.
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linear trend and abrupt changes of climate indices in the Arid Region of northwestern china
Atmospheric Research, 2017Co-Authors: Huaijun Wang, Yaning Chen, Zhengwei YeAbstract:Abstract In recent years, climate extreme events have caused increasing direct economic and social losses in the Arid Region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with − 1.89%days/decade, 0.65 °C/decade and − 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual Regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the Regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices, which will have serious impacts on water resources and ecological environment in the Arid Region of China.
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comparison of three drought indices and their evolutionary characteristics in the Arid Region of northwestern china
Atmospheric Science Letters, 2017Co-Authors: Huaijun Wang, Yingping Pan, Yaning ChenAbstract:Drought evolutions in the Arid Region of northwestern China from 1960 to 2010 were analyzed based on the standardized precipitation index (SPI), the standardized precipitation-evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI). All three forms of drought indices were significantly correlated with each other. No statistically significant differences were found for the severity of drought, as assessed by both the SPI and SPEI. The SC-PDSI was generally an index representing water deficits at a medium period. For the entire geographical area of study, wet conditions dominated during 1987–2010, whereas persistent drought conditions occurred from 1960 to 1986.
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progress and prospects of climate change impacts on hydrology in the Arid Region of northwest china
Environmental Research, 2015Co-Authors: Yaning Chen, Huaijun Wang, Zhi Li, Haijun DengAbstract:Abstract The Arid Region of Northwest China, located in the central Asia, responds sensitively to global climate change. Based on the newest research results, this paper analyzes the impacts of climate change on hydrology and the water cycle in the Arid Region of Northwest China. The analysis results show that: (1) In the northwest Arid Region, temperature and precipitation experienced “sharply” increasing in the past 50 years. The precipitation trend changed in 1987, and since then has been in a state of high volatility, during the 21st century, the increasing rate of precipitation was diminished. Temperature experienced a “sharply” increase in 1997; however, this sharp increasing trend has turned to an apparent hiatus since the 21st century. The dramatic rise in winter temperatures in the northwest Arid Region is an important reason for the rise in the average annual temperature, and substantial increases in extreme winter minimum temperature play an important role in the rising average winter temperature; (2) There was a significant turning point in the change of pan evaporation in the northwest Arid area in 1993, i.e., in which a significant decline reversed to a significant upward trend. In the 21st century, the negative effects of global warming and increasing levels of evaporation on the ecology of the northwest Arid Region have been highlighted; (3) Glacier change has a significant impact on hydrology in the northwest Arid area, and glacier inflection points have appeared in some rivers. The melting water supply of the Tarim River Basin possesses a large portion of water supplies (about 50%). In the future, the amount of surface water will probably remain at a high state of fluctuation.
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spatial distribution and temporal trends of mean precipitation and extremes in the Arid Region northwest of china during 1960 2010
Hydrological Processes, 2013Co-Authors: Huaijun Wang, Yaning Chen, Zhongsheng ChenAbstract:On the basis of daily precipitation records at 76 meteorological stations in the Arid Region, northwest of China, the spatial and temporal distribution of mean precipitation and extremes were analysed during 1960–2010. The Mann–Kendall trend test and linear least square method were utilized to detect monotonic trends and magnitudes in annual and seasonal mean precipitation and extremes. The results obtained indicate that both the mean precipitation and the extremes have increased except in consecutive dry days, which showed the opposite trend. The changes in amplitude of both mean precipitation and extremes show seasonal variability. On an annual basis, the number of rain days (R0.1) has significantly increased. Meanwhile, the precipitation intensity as reflected by simple daily intensity index (SDII), number of heavy precipitation days (R10), very wet days (R95p), max 1-day precipitation amount (RX1day) and max 5-day precipitation amount (RX5day) has also significantly increased. This suggests that the precipitation increase in the Arid Region is due to the increase in both precipitation frequency and intensity. Trends in extremes are very highly correlated with mean trends of precipitation. The spatial correlation between trends in extremes and trends in the mean is stronger for winter (DJF) than for annual and other seasons. The Regional annual and seasonal precipitation and extremes are observed the step jump in mean in the late 1980s. Overall, the results of this study are good indicators of local climate change, which will definitely enhance human mitigation to natural hazards caused by precipitation extremes. Copyright © 2012 John Wiley & Sons, Ltd.
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runoff responses to climate change in Arid Region of northwestern china during 1960 2010
Chinese Geographical Science, 2013Co-Authors: Huaijun Wang, Yaning Chen, Haijun DengAbstract:Based on runoff, air temperature, and precipitation data from 1960 to 2010, the effects of climate change on water resources in the Arid Region of the northwestern China were investigated. The long-term trends of hydroclimatic variables were studied by using both Mann-Kendall test and distributed-free cumulative sum (CUSUM) chart test. Results indicate that the mean annual air temperature increases significantly from 1960 to 2010. The annual precipitation exhibits an increasing trend, especially in the south slope of the Tianshan Mountains and the North Uygur Autonomous Region of Xinjiang in the study period. Step changes occur in 1988 in the mean annual air temperature time series and in 1991 in the precipitation time series. The runoff in different basins shows different trends, i.e., significantly increasing in the Kaidu River, the Aksu River and the Shule River, and decreasing in the Shiyang River. Correlation analysis reveals that the runoff in the North Xinjiang (i.e., the Weigan River, the Heihe River, and the Shiyang River) has a strong positive relationship with rainfall, while that in the south slope of the Tianshan Mountains, the middle section of the north slope of the Tianshan Mountains and the Shule River has a strong positive relationship with air temperature. The trends of runoff have strong negative correlations with glacier coverage and the proportion of glacier water in runoff. From the late 1980s, the climate has become warm and wet in the Arid Region of the northwestern China. The change in runoff is interacted with air temperature, precipitation and glacier coverage. The results show that streamflow in the Arid Region of the northwestern China is sensitive to climate change, which can be used as a reference for Regional water resource assessment and management.
Haijun Deng - One of the best experts on this subject based on the ideXlab platform.
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progress and prospects of climate change impacts on hydrology in the Arid Region of northwest china
Environmental Research, 2015Co-Authors: Yaning Chen, Huaijun Wang, Zhi Li, Haijun DengAbstract:Abstract The Arid Region of Northwest China, located in the central Asia, responds sensitively to global climate change. Based on the newest research results, this paper analyzes the impacts of climate change on hydrology and the water cycle in the Arid Region of Northwest China. The analysis results show that: (1) In the northwest Arid Region, temperature and precipitation experienced “sharply” increasing in the past 50 years. The precipitation trend changed in 1987, and since then has been in a state of high volatility, during the 21st century, the increasing rate of precipitation was diminished. Temperature experienced a “sharply” increase in 1997; however, this sharp increasing trend has turned to an apparent hiatus since the 21st century. The dramatic rise in winter temperatures in the northwest Arid Region is an important reason for the rise in the average annual temperature, and substantial increases in extreme winter minimum temperature play an important role in the rising average winter temperature; (2) There was a significant turning point in the change of pan evaporation in the northwest Arid area in 1993, i.e., in which a significant decline reversed to a significant upward trend. In the 21st century, the negative effects of global warming and increasing levels of evaporation on the ecology of the northwest Arid Region have been highlighted; (3) Glacier change has a significant impact on hydrology in the northwest Arid area, and glacier inflection points have appeared in some rivers. The melting water supply of the Tarim River Basin possesses a large portion of water supplies (about 50%). In the future, the amount of surface water will probably remain at a high state of fluctuation.
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abrupt change of temperature and precipitation extremes in the Arid Region of northwest china
Quaternary International, 2014Co-Authors: Yaning Chen, Haijun DengAbstract:Abstract Trends and abrupt detection of temperature and precipitation extremes are important in climate change research. Based on the meteorological data from 68 stations in the Arid Region of Northwest China (ARNC), we analyzed the trend and abrupt change in temperature and precipitation extremes from 1961 to 2010. Results showed that abrupt change in both temperature and precipitation extremes in Northwest China occurred in around 1986. Interestingly, an abrupt change in Index B of the Tibetan Plateau (TPI_B) was detected in 1985. The temperature and precipitation extremes had strong and significant associations with TPI_B over the period of 1961–2010 ( R = 0.685, p R = 0.441, p
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runoff responses to climate change in Arid Region of northwestern china during 1960 2010
Chinese Geographical Science, 2013Co-Authors: Huaijun Wang, Yaning Chen, Haijun DengAbstract:Based on runoff, air temperature, and precipitation data from 1960 to 2010, the effects of climate change on water resources in the Arid Region of the northwestern China were investigated. The long-term trends of hydroclimatic variables were studied by using both Mann-Kendall test and distributed-free cumulative sum (CUSUM) chart test. Results indicate that the mean annual air temperature increases significantly from 1960 to 2010. The annual precipitation exhibits an increasing trend, especially in the south slope of the Tianshan Mountains and the North Uygur Autonomous Region of Xinjiang in the study period. Step changes occur in 1988 in the mean annual air temperature time series and in 1991 in the precipitation time series. The runoff in different basins shows different trends, i.e., significantly increasing in the Kaidu River, the Aksu River and the Shule River, and decreasing in the Shiyang River. Correlation analysis reveals that the runoff in the North Xinjiang (i.e., the Weigan River, the Heihe River, and the Shiyang River) has a strong positive relationship with rainfall, while that in the south slope of the Tianshan Mountains, the middle section of the north slope of the Tianshan Mountains and the Shule River has a strong positive relationship with air temperature. The trends of runoff have strong negative correlations with glacier coverage and the proportion of glacier water in runoff. From the late 1980s, the climate has become warm and wet in the Arid Region of the northwestern China. The change in runoff is interacted with air temperature, precipitation and glacier coverage. The results show that streamflow in the Arid Region of the northwestern China is sensitive to climate change, which can be used as a reference for Regional water resource assessment and management.
D M Muir - One of the best experts on this subject based on the ideXlab platform.
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pressure acid leaching of Arid Region nickel laterite ore part i effect of water quality
Hydrometallurgy, 2003Co-Authors: B I Whittington, J.a. Johnson, R.g. Mcdonald, D M MuirAbstract:The effect of water salinity on the reactions occurring during pressure acid leaching of an Arid-Region laterite ore, using hypersaline water, seawater, sub-potable water and tap water, is examined. Particular emphasis is placed on the mineralogy of the residue and its implications with regard to residue volume/mass, overall acid consumption and nickel extraction. Analysis of a pressure acid leach residue by electron microprobe indicates that the residual nickel is present in phases that contain silicon and varying concentrations of aluminium, but are deficient in sulphur. Incomplete extraction of nickel from the ore may not be attributed to any one mineral phase.
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pressure acid leaching of Arid Region nickel laterite ore part ii effect of ore type
Hydrometallurgy, 2003Co-Authors: B I Whittington, J.a. Johnson, R.g. Mcdonald, L P Quan, D M MuirAbstract:A comparison of the leach chemistry and residue mineralogy has been carried out on the pressure acid leaching of nontronite, limonite and saprolite ores, using hypersaline water. Results are also compared with a typical Arid-Region laterite feed from Bulong, which consists of a blend of these ore types. Particular emphasis is placed on the influence of ore type on liquor analysis of iron, aluminium and magnesium, residue mineralogy and nickel extraction. Microprobe evidence is presented that incomplete nickel extraction results from the presence of unreacted minor phases present in the original ore, or from the presence of nickel in the amorphous silica, in apparent association with magnesium.
Polpass Arul Jose - One of the best experts on this subject based on the ideXlab platform.
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biosynthetic potential of bioactive streptomycetes isolated from Arid Region of the thar desert rajasthan india
Frontiers in Microbiology, 2018Co-Authors: Meeta Masand, Kunjukrishnan Kamalakshi Sivakala, Ekta Menghani, Thangathurai Thinesh, Rangasamy Anandham, Gaurav Sharma, Natesan Sivakumar, Solomon Robinson David Jebakumar, Polpass Arul JoseAbstract:Acquisition of Actinobacteria, especially Streptomyces from previously underexplored habitats and the exploration of their biosynthetic potential have gained much attention in the rejuvenated antibiotics search programs. Herein, we isolated some Streptomyces strains, from an Arid Region of the Great Indian Thar Desert, which possess an ability to produce novel bioactive compounds. Twenty-one morphologically distinctive strains differing in their aerial and substrate mycelium were isolated by employing a stamping method. Among them, 12 strains were identified by a two-level antimicrobial screening method, exerting antimicrobial effects against a panel of indicator strains including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus species. Based on their potent antimicrobial activity, four isolates were further explored by 16S rRNA gene-based identification, genetic screening, and metabolomic analysis; and it was found that these strains belong to the genus Streptomyces. The selected strains were found to have polyketide synthase and non-ribosomal peptide synthetase systems. In addition, extracellular metabolomic screening revealed that the isolates produced analogs of doxorubicinol, pyrromycin, erythromycin, and 6-13 other putative novel metabolites. These results demonstrate the significance of Streptomyces inhabiting the Arid Region of Thar Desert, suggesting that similar Arid environments can be considered as the reservoirs of novel Streptomyces strains that could have biotechnological significance.
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Data_Sheet_1_Biosynthetic Potential of Bioactive Streptomycetes Isolated From Arid Region of the Thar Desert, Rajasthan (India).pdf
2018Co-Authors: Meeta Masand, Kunjukrishnan Kamalakshi Sivakala, Ekta Menghani, Thangathurai Thinesh, Rangasamy Anandham, Gaurav Sharma, Natesan Sivakumar, Solomon Robinson David Jebakumar, Polpass Arul JoseAbstract:Acquisition of Actinobacteria, especially Streptomyces from previously underexplored habitats and the exploration of their biosynthetic potential have gained much attention in the rejuvenated antibiotics search programs. Herein, we isolated some Streptomyces strains, from an Arid Region of the Great Indian Thar Desert, which possess an ability to produce novel bioactive compounds. Twenty-one morphologically distinctive strains differing in their aerial and substrate mycelium were isolated by employing a stamping method. Among them, 12 strains were identified by a two-level antimicrobial screening method, exerting antimicrobial effects against a panel of indicator strains including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus species. Based on their potent antimicrobial activity, four isolates were further explored by 16S rRNA gene-based identification, genetic screening, and metabolomic analysis; and it was found that these strains belong to the genus Streptomyces. The selected strains were found to have polyketide synthase and non-ribosomal peptide synthetase systems. In addition, extracellular metabolomic screening revealed that the isolates produced analogs of doxorubicinol, pyrromycin, erythromycin, and 6-13 other putative novel metabolites. These results demonstrate the significance of Streptomyces inhabiting the Arid Region of Thar Desert, suggesting that similar Arid environments can be considered as the reservoirs of novel Streptomyces strains that could have biotechnological significance.