Global warming has altered the thermodynamic and dynamic environments of the climate system, thus affecting the energy budget and water cycle process of the land-atmosphere system. Under changes in key hydrological el...Global warming has altered the thermodynamic and dynamic environments of the climate system, thus affecting the energy budget and water cycle process of the land-atmosphere system. Under changes in key hydrological elements such as precipitation, runoff, and terrestrial water storage, future drought variation remains a complex question. Existing studies have utilized terrestrial water storage anomaly(TWSA) in drought monitoring and assessment, but they usually focused on either drought duration or intensity, overlooking the multi-faced attributes of droughts as well as their socioeconomic impacts under a non-stationary condition. In this study, we first identify dry/wet conditions over China using GRACE/GRACE-FO satellite observations, and then evaluate the feedback effects of humidity and energy factors(e.g., sensible heat flux, latent heat flux,atmospheric relative humidity, and convective available potential energy) to drought events. Future changes in TWSA and dry/wet conditions are projected by eight Coupled Model Inter-comparison Project Phase 6(CMIP6) global climate models(GCMs)under three shared socioeconomic pathways(SSPs), with their biases corrected by a trend-preserving quantile mapping method.The time-varying Copula function of drought duration and intensity is constructed by a moving windows method, and future bivariate drought risks are quantified with the most likely realization method. The population and GDP affected by increasing drought risks are finally quantified based on the SSPs data. It is found that the land-atmosphere coupling effects closely interact with drought evolution, and the uneven distribution of water resources is projected to be further aggravated, with most areas of China will be threatened by continuous drying tendency. By the end of the century, the duration of moderate, severe and exceptional droughts in some regions of China will double, and the drought intensity will increase by over 80%. For the 50-year bivariate droughts during the historical period, their occurrence may increase by 5–10 times in several regions, and might affect about 35–55% of China’s population and GDP at the end of 21st century.展开更多
Background The micropattern gaseous detectors(MPGDs)are widely used in high-energy physics experiment,such as detector upgrade projects in LHC,due to its excellent performance on rate capability,spatial and time resol...Background The micropattern gaseous detectors(MPGDs)are widely used in high-energy physics experiment,such as detector upgrade projects in LHC,due to its excellent performance on rate capability,spatial and time resolutions.Method In this paper,we studied the performances of GEM,FTM andμ-RWELL detectors on time and spatial resolutions using Monte Carlo simulation methods and compared their performances and characteristics at various working conditions.Result Result shows that time resolution of MPGDs improves with the increase of electric field intensity in drift region,while spatial resolution shows the reverse tendency.In addition,detectors operating with an electronegative gas mixture show better performances on both time and spatial resolution.Conclusion We studied the performance of triple-GEM,FTM andμ-RWELL detectors with Monte Carlo simulation.In this paper,ANSYS and GARFIELD are used to build full electric field model of the detector.The time resolution and spatial resolution are derived,which are very important for triggering performance and track reconstruction ability.These results will provide references on detector design and the technology chosen in LHC detector upgrade projects.展开更多
Climate change and land use/cover change(LUCC)can both exert great impacts on the generation processes of precipitation and runoff.However,previous studies usually neglected considering the contribution component of f...Climate change and land use/cover change(LUCC)can both exert great impacts on the generation processes of precipitation and runoff.However,previous studies usually neglected considering the contribution component of future LUCC in evaluating changes in hydrological cycles.In this study,an integrated framework is developed to quantify and partition the impact of climate change and LUCC on future runoff evolution.First,a daily bias correction(DBC)method and the Cellular Automaton-Markov(CA-Markov)model are used to project future climate and LUCC scenarios,and then future runoff is simulated by the calibrated Soil and Water Assessment Tool(SWAT)model with different climate and LUCC scenarios.Finally,the uncertainty of future runoff and the contribution rate of the two driving factors are systematically quantified.The Han River basin in China was selected as a case study.Results indicate that:1)both climate change and LUCC will contribute to future runoff intensification,the variation of future runoff under combined climate and LUCC is larger than these under climate change or LUCC alone;2)the projected uncertainty of median value of multi-models under RCP4.5(RCP8.5)will reach 18.14%(20.34%),12.18%(14.71%),11.01%(13.95%),and 11.41%(14.34%)at Baihe,Ankang,Danjiangkou,and Huangzhuang stations,respectively;3)the contribution rate of climate change to runoff at Baihe,Ankang,Danjiangkou,and Huangzhuang stations under RCP4.5(RCP8.5)are 91%-98%(84%-94%),while LUCC to runoff under RCP4.5(RCP8.5)only accounts for 2%-9%(6%-16%)in the annual scale.This study may provide useful adaptive strategies for policymakers on future water resources planning and management.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 52009091)the Fundamental Research Funds for the Central Universities (Grant No. 2042022kf1221)。
文摘Global warming has altered the thermodynamic and dynamic environments of the climate system, thus affecting the energy budget and water cycle process of the land-atmosphere system. Under changes in key hydrological elements such as precipitation, runoff, and terrestrial water storage, future drought variation remains a complex question. Existing studies have utilized terrestrial water storage anomaly(TWSA) in drought monitoring and assessment, but they usually focused on either drought duration or intensity, overlooking the multi-faced attributes of droughts as well as their socioeconomic impacts under a non-stationary condition. In this study, we first identify dry/wet conditions over China using GRACE/GRACE-FO satellite observations, and then evaluate the feedback effects of humidity and energy factors(e.g., sensible heat flux, latent heat flux,atmospheric relative humidity, and convective available potential energy) to drought events. Future changes in TWSA and dry/wet conditions are projected by eight Coupled Model Inter-comparison Project Phase 6(CMIP6) global climate models(GCMs)under three shared socioeconomic pathways(SSPs), with their biases corrected by a trend-preserving quantile mapping method.The time-varying Copula function of drought duration and intensity is constructed by a moving windows method, and future bivariate drought risks are quantified with the most likely realization method. The population and GDP affected by increasing drought risks are finally quantified based on the SSPs data. It is found that the land-atmosphere coupling effects closely interact with drought evolution, and the uneven distribution of water resources is projected to be further aggravated, with most areas of China will be threatened by continuous drying tendency. By the end of the century, the duration of moderate, severe and exceptional droughts in some regions of China will double, and the drought intensity will increase by over 80%. For the 50-year bivariate droughts during the historical period, their occurrence may increase by 5–10 times in several regions, and might affect about 35–55% of China’s population and GDP at the end of 21st century.
基金This work is supported by Ministry of Science and Technology of China(10935008)National Natural Science Foundation of China(11461141011).
文摘Background The micropattern gaseous detectors(MPGDs)are widely used in high-energy physics experiment,such as detector upgrade projects in LHC,due to its excellent performance on rate capability,spatial and time resolutions.Method In this paper,we studied the performances of GEM,FTM andμ-RWELL detectors on time and spatial resolutions using Monte Carlo simulation methods and compared their performances and characteristics at various working conditions.Result Result shows that time resolution of MPGDs improves with the increase of electric field intensity in drift region,while spatial resolution shows the reverse tendency.In addition,detectors operating with an electronegative gas mixture show better performances on both time and spatial resolution.Conclusion We studied the performance of triple-GEM,FTM andμ-RWELL detectors with Monte Carlo simulation.In this paper,ANSYS and GARFIELD are used to build full electric field model of the detector.The time resolution and spatial resolution are derived,which are very important for triggering performance and track reconstruction ability.These results will provide references on detector design and the technology chosen in LHC detector upgrade projects.
基金supported by the National Natural Science Foundation of China(Grant Nos.U20A20317 and 51539009).
文摘Climate change and land use/cover change(LUCC)can both exert great impacts on the generation processes of precipitation and runoff.However,previous studies usually neglected considering the contribution component of future LUCC in evaluating changes in hydrological cycles.In this study,an integrated framework is developed to quantify and partition the impact of climate change and LUCC on future runoff evolution.First,a daily bias correction(DBC)method and the Cellular Automaton-Markov(CA-Markov)model are used to project future climate and LUCC scenarios,and then future runoff is simulated by the calibrated Soil and Water Assessment Tool(SWAT)model with different climate and LUCC scenarios.Finally,the uncertainty of future runoff and the contribution rate of the two driving factors are systematically quantified.The Han River basin in China was selected as a case study.Results indicate that:1)both climate change and LUCC will contribute to future runoff intensification,the variation of future runoff under combined climate and LUCC is larger than these under climate change or LUCC alone;2)the projected uncertainty of median value of multi-models under RCP4.5(RCP8.5)will reach 18.14%(20.34%),12.18%(14.71%),11.01%(13.95%),and 11.41%(14.34%)at Baihe,Ankang,Danjiangkou,and Huangzhuang stations,respectively;3)the contribution rate of climate change to runoff at Baihe,Ankang,Danjiangkou,and Huangzhuang stations under RCP4.5(RCP8.5)are 91%-98%(84%-94%),while LUCC to runoff under RCP4.5(RCP8.5)only accounts for 2%-9%(6%-16%)in the annual scale.This study may provide useful adaptive strategies for policymakers on future water resources planning and management.
