On the basis of analyzing the importance of cryospheric researches in China and current status of cryospheric sciences in the world, this paper addresses key issues and main contents of present cryospheric sciences in...On the basis of analyzing the importance of cryospheric researches in China and current status of cryospheric sciences in the world, this paper addresses key issues and main contents of present cryospheric sciences in China. The key issues currently addressed are： i） mechanisms of different types of glaciers in response to climate change and the scale-conversion in water resources assessments; ii） modeling of water and heat exchanges between frozen soil and vegetation; iii） parameterization of physical processes in cryosphere as well as coupling with climate models. To gain full clarification of these key issues, works of the following three aspects should be highlighted, i.e., cryospheric processes and responses to climate change, influences of cryospheric changes, and adaptation strategies for cryospheric changes.展开更多
in the latest version of the international Centre for Theoretical Physics＇ regional climate model, RegCM4, CLM was introduced as a new land surface scheme. The performance over China of RegCM4-CLM with different conv...in the latest version of the international Centre for Theoretical Physics＇ regional climate model, RegCM4, CLM was introduced as a new land surface scheme. The performance over China of RegCM4-CLM with different convection schemes is analyzed in this study, based on a series of short- term experiments.The model is driven by ERA-Interim data at a grid spacing of 25 km.The convection schemes employed are： Emanuel; Grell; Emanuel over land and Grell over ocean; Grell over land and Emanuel over ocean; and Tiedtke. The simulated mean surface air temperature and precipitation in December-February-January and June-July-August are compared against observation. In general, better performance of Emanuel is found both for temperature and precipitation, and in both seasons. Thus, the model physics of CLM and Emanuel for the land surface processes and convection, respectively, are recommended for further application of RegCM4 over the China region. The de^ciencies that remain in the model arealso outlined and discussed.展开更多
The future climate dynamical downscaling method is that output of general circulation models( GCMs) is employed to provide initial conditions,lateral boundary conditions,sea surface temperatures,and initial land surfa...The future climate dynamical downscaling method is that output of general circulation models( GCMs) is employed to provide initial conditions,lateral boundary conditions,sea surface temperatures,and initial land surface conditions to regional climate models( RCMs). There are two methods of downscaling: offline coupling and online coupling. The two kinds of coupling methods are described in detail by coupling the Weather Research and Forecasting model( WRF) with the Institute of Atmospheric Physics of Chinese Academy of Sciences Atmospheric General Circulation Model Version 4. 0( IAP AGCM4. 0) in the study. And the extreme precipitation event over Beijing on July 212012 is simulated by using the two coupling methods. Results show that online coupling method is of great value in improving the model simulation. Furthermore,the data exchange frequency of online coupling has some effect on simulation result.展开更多
This paper presents projections of climate extremes over China under global warming of 1.5,2,and 3℃ above pre-industrial(1861–1900),based on the latest Coupled Model Intercomparison Project phase 6(CMIP6)simulations...This paper presents projections of climate extremes over China under global warming of 1.5,2,and 3℃ above pre-industrial(1861–1900),based on the latest Coupled Model Intercomparison Project phase 6(CMIP6)simulations.Results are compared with what produced by the precedent phase of the project,CMIP5.Model evaluation for the reference period(1985–2005)indicates that CMIP6 models outperform their predecessors in CMIP5,especially in simulating precipitation extremes.Areal averages for changes of most indices are found larger in CMIP6 than in CMIP5.The emblematic annual mean temperature,when averaged over the whole of China in CMIP6,increases by 1.49,2.21,and 3.53℃(relative to1985–2005)for 1.5,2,and 3℃ above-preindustrial global warming levels,while the counterpart in CMIP5 is 1.20,1.93 and 3.39℃ respectively.Similarly,total precipitation increases by 5.3%,8.6%,and16.3%in CMIP6 and by 4.4%,7.0%and 12.8%in CMIP5,respectively.The spatial distribution of changes for extreme indices is generally consistent in both CMIP5 and CMIP6,but with significantly higher increases in CMIP6 over Northeast and Northwest China for the hottest day temperature,and South China for the coldest night temperature.In the south bank of the Yangtze River,and most regions around40°N,CMIP6 shows higher increases for both total precipitation and heavy precipitation.The projected difference between CMIP6 and CMIP5 is mainly attributable to the physical upgrading of climate models and largely independent from their emission scenarios.展开更多
基金the Nation Basic Research Program of China(973 Program,Research No.2007CB411500)
文摘On the basis of analyzing the importance of cryospheric researches in China and current status of cryospheric sciences in the world, this paper addresses key issues and main contents of present cryospheric sciences in China. The key issues currently addressed are： i） mechanisms of different types of glaciers in response to climate change and the scale-conversion in water resources assessments; ii） modeling of water and heat exchanges between frozen soil and vegetation; iii） parameterization of physical processes in cryosphere as well as coupling with climate models. To gain full clarification of these key issues, works of the following three aspects should be highlighted, i.e., cryospheric processes and responses to climate change, influences of cryospheric changes, and adaptation strategies for cryospheric changes.
基金supported by the National Natural Science Foundation of China[41375104]the Climate Change Specific Fund of China[CCSF201509]
文摘in the latest version of the international Centre for Theoretical Physics＇ regional climate model, RegCM4, CLM was introduced as a new land surface scheme. The performance over China of RegCM4-CLM with different convection schemes is analyzed in this study, based on a series of short- term experiments.The model is driven by ERA-Interim data at a grid spacing of 25 km.The convection schemes employed are： Emanuel; Grell; Emanuel over land and Grell over ocean; Grell over land and Emanuel over ocean; and Tiedtke. The simulated mean surface air temperature and precipitation in December-February-January and June-July-August are compared against observation. In general, better performance of Emanuel is found both for temperature and precipitation, and in both seasons. Thus, the model physics of CLM and Emanuel for the land surface processes and convection, respectively, are recommended for further application of RegCM4 over the China region. The de^ciencies that remain in the model arealso outlined and discussed.
基金Supported by the National Natural Science Foundation of China(No.61602477)China Postdoctoral Science Foundation(No.2016M601158)National Key Research and Development Program of China(No.2016YFB0200804)
文摘The future climate dynamical downscaling method is that output of general circulation models( GCMs) is employed to provide initial conditions,lateral boundary conditions,sea surface temperatures,and initial land surface conditions to regional climate models( RCMs). There are two methods of downscaling: offline coupling and online coupling. The two kinds of coupling methods are described in detail by coupling the Weather Research and Forecasting model( WRF) with the Institute of Atmospheric Physics of Chinese Academy of Sciences Atmospheric General Circulation Model Version 4. 0( IAP AGCM4. 0) in the study. And the extreme precipitation event over Beijing on July 212012 is simulated by using the two coupling methods. Results show that online coupling method is of great value in improving the model simulation. Furthermore,the data exchange frequency of online coupling has some effect on simulation result.
基金supported by the National Key Research and Development Program of China(2017YFA0603804,2016YFA0600402,and 2018YFC1507704)。
文摘This paper presents projections of climate extremes over China under global warming of 1.5,2,and 3℃ above pre-industrial(1861–1900),based on the latest Coupled Model Intercomparison Project phase 6(CMIP6)simulations.Results are compared with what produced by the precedent phase of the project,CMIP5.Model evaluation for the reference period(1985–2005)indicates that CMIP6 models outperform their predecessors in CMIP5,especially in simulating precipitation extremes.Areal averages for changes of most indices are found larger in CMIP6 than in CMIP5.The emblematic annual mean temperature,when averaged over the whole of China in CMIP6,increases by 1.49,2.21,and 3.53℃(relative to1985–2005)for 1.5,2,and 3℃ above-preindustrial global warming levels,while the counterpart in CMIP5 is 1.20,1.93 and 3.39℃ respectively.Similarly,total precipitation increases by 5.3%,8.6%,and16.3%in CMIP6 and by 4.4%,7.0%and 12.8%in CMIP5,respectively.The spatial distribution of changes for extreme indices is generally consistent in both CMIP5 and CMIP6,but with significantly higher increases in CMIP6 over Northeast and Northwest China for the hottest day temperature,and South China for the coldest night temperature.In the south bank of the Yangtze River,and most regions around40°N,CMIP6 shows higher increases for both total precipitation and heavy precipitation.The projected difference between CMIP6 and CMIP5 is mainly attributable to the physical upgrading of climate models and largely independent from their emission scenarios.
