Multi-year experiments are conducted using the most recent version of the Abdus Salam International Centre for Theoretical Physics regional climate model RegCM4(version 4.7) to customize its performance over Southeast...Multi-year experiments are conducted using the most recent version of the Abdus Salam International Centre for Theoretical Physics regional climate model RegCM4(version 4.7) to customize its performance over Southeast Asia - a region with few RCMs applied to date. The model is driven by ERA-Interim reanalysis data at a grid spacing of 25 km using the CORDEX(Coordinated Regional Climate Downscaling Experiment) Southeast Asia domain. The authors focus on comparing the convection schemes of Emanuel and Tiedtke(Tiedtke-1) and Tiedtke with effects of sea surface evaporation introduced(Tiedtke-2). The authors find that, for temperature over land, the model shows reasonable performance in reproducing the present-day climatology in both December–January–February(DJF) and June–July–August(JJA) in all the experiments. Meanwhile, cold biases prevail in both seasons, although portions of warm bias exist in DJF. For precipitation, the spatial pattern and amount, as well as seasonal evolution, are in general reproduced well in the experiments.Better performances of Tiedtke-1 and Tiedtke-2 are evident compared to Emanuel, particularly over ocean. Thereby, the optimal configuration of Reg CM4.7 for future climate change simulations over the region is identified as using the Tiedtke scheme with spray effects considered, along with the default settings for other physical parameterizations.展开更多
Corrosion fatigue under the load of low frequency and bigh mean stress has been generally defined as stress corrosion fatigue(SCF).It is a specific failure process due to the inter- action between stress corrosion cra...Corrosion fatigue under the load of low frequency and bigh mean stress has been generally defined as stress corrosion fatigue(SCF).It is a specific failure process due to the inter- action between stress corrosion cracking(SCC) and corrsion fatigue(CF),the effects of which on fracture characteristics,including crack initiation and propagation.service life and cracking mode have not been investigated systematically.The purpose of this pa- per was to study the environment-sensitive fracture behaviour of OCr18Ni9Ti austenitic stainless steel under the load of different fiequencies and high mean stress in boiling MgCl_2 solution.The interaction between SCC and CF would be emphasized.展开更多
A regional climate model(RegCM4)is used to project climate change over China in the twenty-first century under the RCP4.5 and RCP8.5 pathways.The driving GCM is CSIRO Mk3.6.0(hereafter referred to simply as CSIRO),and...A regional climate model(RegCM4)is used to project climate change over China in the twenty-first century under the RCP4.5 and RCP8.5 pathways.The driving GCM is CSIRO Mk3.6.0(hereafter referred to simply as CSIRO),and the simulation(hereafter referred to as CdR)is run at a grid spacing of 25 km.The focus of the present paper is on the changes in mean surface air temperature and precipitation in December–January–February(DJF)and June–July–August(JJA)over China.Validation of the model performances is provided first,followed by a comparison of future changes projected by CSIRO and CdR.Substantial warming in the future is simulated by both models,being more pronounced in DJF compared to JJA,and under RCP8.5 compared to RCP4.5.The warming shows different spatial patterns and,to a less extent,magnitude between CSIRO and CdR.Precipitation change shows a general increase in DJF and a mixture of increase and decrease in JJA.Substantial differences between the two models are found in for precipitation change in JJA.The paper further emphasizes the uncertainties in climate change projection over the region.展开更多
Climate change in the 21st century over China is simulated using the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3). The model is one-way nested within the gl...Climate change in the 21st century over China is simulated using the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3). The model is one-way nested within the global model CCSR/NIES/FRCGC MIROC3.2_hires (Center for Climate System Research/National Institute for Environmental Studies/Frontier Research Center for Global Change/Model for Interdisciplinary Research on Climate). A 150-year (1951-2100) transient simulation is conducted at 25 km grid spacing, under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A1B scenario. Simulations of present climate conditions in China by RegCM3 are compared against observations to assess model performance. Results show that RegCM3 reproduces the observed spatial structure of surface air temperature and precipitation well. Changes in mean temperature and precipitation in December-January-February (DJF) and June-July-August (JJA) during the middle and end of the 21st century are analyzed. Significant future warming is simulated by RegCM3. This warming becomes greater with time, and increased warming is simulated at high latitude and high altitude (Tibetan Plateau) areas. In the middle of the 21st century in DJF, a general increase of precipitation is found in most areas, except over the Tibetan Plateau. Precipitation changes in JJA show an increase over northwest China and a decrease over the Tibetan Plateau. There is a mixture of positive and negative changes in eastern China. The change pattern at the end of the century is generally consistent with that in mid century, except in some small areas, and the magnitude of change is usually larger. In addition, the simulation is compared with a previous simulation of the RegCM3 driven by a different global model, to address uncertainties of the projected climate change in China.展开更多
Based on a consecutive simulation of the 21st century conducted by RegCM3, changes in climate extremes over China are investigated, following abasic validation of the model performances in simulating present climate. ...Based on a consecutive simulation of the 21st century conducted by RegCM3, changes in climate extremes over China are investigated, following abasic validation of the model performances in simulating present climate. The model is one-way nested within the global model of CCSR/NIES/FRCGC MIROC3.2_hires. A total of 150-years (1951-2100) transient simulation is carried out at 25 km grid spacing under the IPCC SRES A1B scenario. The indices of the extremesincludes SU (summer days), FD (frost days), GSL (growing season length) for temperature, SDII (simple daily intensity index), R10 (no. of days with precipitation 10 mm/d), and CDD (consecutive dry days) for precipitation. Results show that the model can reproduce both the spatial distribution and the values of the present day annual mean temperature and precipitationwell, and it also shows good performances in simulating the extreme indices. Following the significant warming, the indices of SU and GSL for warm events will increase while the indices of FD for cold events will decrease over China. Heavy precipitation events as measured by SDII and R10 show an general increase over the region, except the decrease ofR10 in the Northeast and central Tibetan Plateau andless change or decrease of it along the middle and lower reaches of the Yangtze River. Decrease of drynessas measured by CDD over northern part of China while increase of it over the Tibetan Plateau, Sichuan Basin and other places in southern China are simulated by the model. This leads to the less change of the regional mean CDD in the time series in the 21st century unlike the other indices, which show clear trend of change following the time evolution.展开更多
Multi-decadal high resolution climate change simulations over East Asia were performed by using The Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3), nested within the NA...Multi-decadal high resolution climate change simulations over East Asia were performed by using The Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3), nested within the NASA/NCAR global model FvGCM/CCM3. Two sets of simulations were conducted at 20-km grid spacings, one for present day (1961-1990) and one for the future climate (2071-2100, IPCC A2 scenario). Simulations of present climate conditions over China by RegCM3 and FvGCM were compared against observations to assess the model performance. Results showed that both models repro- duced the observed spatial structure of 500 hPa height, surface air temperature and precipitation. Compared with FvGCM, RegCM3 provided increasing spatial detail of surface variables. Furthermore, RegCM3 improved the simulation of monsoon precipitation over the region. Changes in the mean temperature and precipitation were analyzed and compared between the two models. Significant warming in the end of the 21st century was simulated by both models in December-January-February (DJF), June-July-August (JJA), and the annual mean. In DJF, greater warming was simulated by FvGCM over Northeast and Northwest China, as well as the Tibetan Plateau, compared with RegCM. In JJA, RegCM3 simulated greater warming over northern China, Inner Mongolia, Northwest China, and the Tibetan Plateau. Simulated changes in DJF precipitation showed similar spatial patterns between the two models. In JJA, while FvGCM projected a prevailing increase of monsoon precipitation over China, which is in agreement with other global models, RegCM3 projected extended areas of decreased precipitation. Changes in the variability for annual mean temperature and precipitation also are presented.展开更多
基金This research was jointly supported by the Strategic Priority Research Programme of Chinese Academy of Sciences[grant number Y86101|601]the National Natural Science Foundation of China[grant numbers 41675103 and 41861144015].
文摘Multi-year experiments are conducted using the most recent version of the Abdus Salam International Centre for Theoretical Physics regional climate model RegCM4(version 4.7) to customize its performance over Southeast Asia - a region with few RCMs applied to date. The model is driven by ERA-Interim reanalysis data at a grid spacing of 25 km using the CORDEX(Coordinated Regional Climate Downscaling Experiment) Southeast Asia domain. The authors focus on comparing the convection schemes of Emanuel and Tiedtke(Tiedtke-1) and Tiedtke with effects of sea surface evaporation introduced(Tiedtke-2). The authors find that, for temperature over land, the model shows reasonable performance in reproducing the present-day climatology in both December–January–February(DJF) and June–July–August(JJA) in all the experiments. Meanwhile, cold biases prevail in both seasons, although portions of warm bias exist in DJF. For precipitation, the spatial pattern and amount, as well as seasonal evolution, are in general reproduced well in the experiments.Better performances of Tiedtke-1 and Tiedtke-2 are evident compared to Emanuel, particularly over ocean. Thereby, the optimal configuration of Reg CM4.7 for future climate change simulations over the region is identified as using the Tiedtke scheme with spray effects considered, along with the default settings for other physical parameterizations.
文摘Corrosion fatigue under the load of low frequency and bigh mean stress has been generally defined as stress corrosion fatigue(SCF).It is a specific failure process due to the inter- action between stress corrosion cracking(SCC) and corrsion fatigue(CF),the effects of which on fracture characteristics,including crack initiation and propagation.service life and cracking mode have not been investigated systematically.The purpose of this pa- per was to study the environment-sensitive fracture behaviour of OCr18Ni9Ti austenitic stainless steel under the load of different fiequencies and high mean stress in boiling MgCl_2 solution.The interaction between SCC and CF would be emphasized.
基金supported by the National Key Research and Development Program [grant number 2016YFA0600704]the National Natural Science Foundation of China [grant number 41375104]
文摘A regional climate model(RegCM4)is used to project climate change over China in the twenty-first century under the RCP4.5 and RCP8.5 pathways.The driving GCM is CSIRO Mk3.6.0(hereafter referred to simply as CSIRO),and the simulation(hereafter referred to as CdR)is run at a grid spacing of 25 km.The focus of the present paper is on the changes in mean surface air temperature and precipitation in December–January–February(DJF)and June–July–August(JJA)over China.Validation of the model performances is provided first,followed by a comparison of future changes projected by CSIRO and CdR.Substantial warming in the future is simulated by both models,being more pronounced in DJF compared to JJA,and under RCP8.5 compared to RCP4.5.The warming shows different spatial patterns and,to a less extent,magnitude between CSIRO and CdR.Precipitation change shows a general increase in DJF and a mixture of increase and decrease in JJA.Substantial differences between the two models are found in for precipitation change in JJA.The paper further emphasizes the uncertainties in climate change projection over the region.
基金the National Basic Research Program of China (2009CB421407)China-UK-Swiss Adapting to Climate Change in China Project (ACCC)the Special Research Program for Public-welfare Forestry (200804001)
文摘Climate change in the 21st century over China is simulated using the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model version 3 (RegCM3). The model is one-way nested within the global model CCSR/NIES/FRCGC MIROC3.2_hires (Center for Climate System Research/National Institute for Environmental Studies/Frontier Research Center for Global Change/Model for Interdisciplinary Research on Climate). A 150-year (1951-2100) transient simulation is conducted at 25 km grid spacing, under the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A1B scenario. Simulations of present climate conditions in China by RegCM3 are compared against observations to assess model performance. Results show that RegCM3 reproduces the observed spatial structure of surface air temperature and precipitation well. Changes in mean temperature and precipitation in December-January-February (DJF) and June-July-August (JJA) during the middle and end of the 21st century are analyzed. Significant future warming is simulated by RegCM3. This warming becomes greater with time, and increased warming is simulated at high latitude and high altitude (Tibetan Plateau) areas. In the middle of the 21st century in DJF, a general increase of precipitation is found in most areas, except over the Tibetan Plateau. Precipitation changes in JJA show an increase over northwest China and a decrease over the Tibetan Plateau. There is a mixture of positive and negative changes in eastern China. The change pattern at the end of the century is generally consistent with that in mid century, except in some small areas, and the magnitude of change is usually larger. In addition, the simulation is compared with a previous simulation of the RegCM3 driven by a different global model, to address uncertainties of the projected climate change in China.
基金supported by the National Basic Research Program of China (2009CB421407)Major Science and Technology Projects in Zhejiang Province (2009C03008-2)the National Natural Science Foundation of China (40975041)
文摘Based on a consecutive simulation of the 21st century conducted by RegCM3, changes in climate extremes over China are investigated, following abasic validation of the model performances in simulating present climate. The model is one-way nested within the global model of CCSR/NIES/FRCGC MIROC3.2_hires. A total of 150-years (1951-2100) transient simulation is carried out at 25 km grid spacing under the IPCC SRES A1B scenario. The indices of the extremesincludes SU (summer days), FD (frost days), GSL (growing season length) for temperature, SDII (simple daily intensity index), R10 (no. of days with precipitation 10 mm/d), and CDD (consecutive dry days) for precipitation. Results show that the model can reproduce both the spatial distribution and the values of the present day annual mean temperature and precipitationwell, and it also shows good performances in simulating the extreme indices. Following the significant warming, the indices of SU and GSL for warm events will increase while the indices of FD for cold events will decrease over China. Heavy precipitation events as measured by SDII and R10 show an general increase over the region, except the decrease ofR10 in the Northeast and central Tibetan Plateau andless change or decrease of it along the middle and lower reaches of the Yangtze River. Decrease of drynessas measured by CDD over northern part of China while increase of it over the Tibetan Plateau, Sichuan Basin and other places in southern China are simulated by the model. This leads to the less change of the regional mean CDD in the time series in the 21st century unlike the other indices, which show clear trend of change following the time evolution.
基金supported by the National Basic Research Program of China (Grant No. 2009CB421407)the R & D Special Fund for Public Welfare (Grant Nos. Industry Meteorology-GYHY200806010 and Forestry-200804001)
文摘Multi-decadal high resolution climate change simulations over East Asia were performed by using The Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3), nested within the NASA/NCAR global model FvGCM/CCM3. Two sets of simulations were conducted at 20-km grid spacings, one for present day (1961-1990) and one for the future climate (2071-2100, IPCC A2 scenario). Simulations of present climate conditions over China by RegCM3 and FvGCM were compared against observations to assess the model performance. Results showed that both models repro- duced the observed spatial structure of 500 hPa height, surface air temperature and precipitation. Compared with FvGCM, RegCM3 provided increasing spatial detail of surface variables. Furthermore, RegCM3 improved the simulation of monsoon precipitation over the region. Changes in the mean temperature and precipitation were analyzed and compared between the two models. Significant warming in the end of the 21st century was simulated by both models in December-January-February (DJF), June-July-August (JJA), and the annual mean. In DJF, greater warming was simulated by FvGCM over Northeast and Northwest China, as well as the Tibetan Plateau, compared with RegCM. In JJA, RegCM3 simulated greater warming over northern China, Inner Mongolia, Northwest China, and the Tibetan Plateau. Simulated changes in DJF precipitation showed similar spatial patterns between the two models. In JJA, while FvGCM projected a prevailing increase of monsoon precipitation over China, which is in agreement with other global models, RegCM3 projected extended areas of decreased precipitation. Changes in the variability for annual mean temperature and precipitation also are presented.
