Four sets of climate change simulations at grid spacing of 50 km were conducted over East Asia with two regional climate models driven at the lateral bounda- ries by two global models for the period 1981-2050. The loc...Four sets of climate change simulations at grid spacing of 50 km were conducted over East Asia with two regional climate models driven at the lateral bounda- ries by two global models for the period 1981-2050. The locus of the study was on the ensemble projection of cli- mate change in the mid-21st century （2031-50） over China. Validation of each simulation and the ensemble average showed good performances of the models overall, as well as advantages of the ensemble in reproducing present day （1981 2000） December-February （DJF）, June-August （JJA）, and annual （ANN） mean temperature and precipitation. Significant wanning was projected for the mid-21st century, with larger values of temperature increase found in the northern part of China and in the cold seasons. The ensemble average changes of precipitation in DJF, JJA, and ANN were determined, and the uncertainties of the projected changes analyzed based on the consistencies of the simulations. It was concluded that the largest uncertainties in precipitation projection are in eastern China during the summer season （monsoon pre-cipitation）.展开更多
Driven by the global model,Beijing Climate Center Climate System Model version 1.1(BCC_CSM1.1),climate change over China in the 21st century is simulated by a regional climate model(RegCM4.0)under the new emission sce...Driven by the global model,Beijing Climate Center Climate System Model version 1.1(BCC_CSM1.1),climate change over China in the 21st century is simulated by a regional climate model(RegCM4.0)under the new emission scenarios of the Representative Concentration Pathways—RCP4.5 and RCP8.5.This is based on a period of transient simulations from 1950 to2099,with a grid spacing of 50 km.The present paper focuses on the annual mean temperature and precipitation in China over this period,with emphasis on their future changes.Validation of model performance reveals marked improvement of the RegCM4.0 model in reproducing present day temperature and precipitation relative to the driving BCC_CSM1.1 model.Significant warming is simulated by both BCC_CSM1.1 and RegCM4.0,however,spatial distribution and magnitude differ between the simulations.The high emission scenario RCP8.5 results in greater warming compared to RCP4.5.The two models project different precipitation changes,characterized by a general increase in the BCC_CSM1.1,and broader areas with decrease in the RegCM4.0 simulations.展开更多
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 hydr...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 analy- sis 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 rtmoff have strong negative correla- tions 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.展开更多
基金supported by the R&D Special Fund for Public Welfare Industry (Meteorology) (Grant No. GYHY201306019)the National Natural Science Foundation of China (Grant No. 41375104)the China-UK-Swiss Adapting to Climate Change in China Project (ACCC)-Climate Science
文摘Four sets of climate change simulations at grid spacing of 50 km were conducted over East Asia with two regional climate models driven at the lateral bounda- ries by two global models for the period 1981-2050. The locus of the study was on the ensemble projection of cli- mate change in the mid-21st century （2031-50） over China. Validation of each simulation and the ensemble average showed good performances of the models overall, as well as advantages of the ensemble in reproducing present day （1981 2000） December-February （DJF）, June-August （JJA）, and annual （ANN） mean temperature and precipitation. Significant wanning was projected for the mid-21st century, with larger values of temperature increase found in the northern part of China and in the cold seasons. The ensemble average changes of precipitation in DJF, JJA, and ANN were determined, and the uncertainties of the projected changes analyzed based on the consistencies of the simulations. It was concluded that the largest uncertainties in precipitation projection are in eastern China during the summer season （monsoon pre-cipitation）.
基金supported by the National Basic Research Program of China (Grant No. 2010CB 950903)the China-UK-Swiss Adapting to Climate Change in China Project (ACCC)-Climate Science
文摘Driven by the global model,Beijing Climate Center Climate System Model version 1.1(BCC_CSM1.1),climate change over China in the 21st century is simulated by a regional climate model(RegCM4.0)under the new emission scenarios of the Representative Concentration Pathways—RCP4.5 and RCP8.5.This is based on a period of transient simulations from 1950 to2099,with a grid spacing of 50 km.The present paper focuses on the annual mean temperature and precipitation in China over this period,with emphasis on their future changes.Validation of model performance reveals marked improvement of the RegCM4.0 model in reproducing present day temperature and precipitation relative to the driving BCC_CSM1.1 model.Significant warming is simulated by both BCC_CSM1.1 and RegCM4.0,however,spatial distribution and magnitude differ between the simulations.The high emission scenario RCP8.5 results in greater warming compared to RCP4.5.The two models project different precipitation changes,characterized by a general increase in the BCC_CSM1.1,and broader areas with decrease in the RegCM4.0 simulations.
基金Under the auspices of Major State Basic Research Development Program of China(No.2010CB951003)the National Climate Central,China Meteorological Administration,for providing the meteorological data for this study
文摘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 analy- sis 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 rtmoff have strong negative correla- tions 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.
