This paper examines the performance of an atmospheric general circulation model (AGCM) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of ...This paper examines the performance of an atmospheric general circulation model (AGCM) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics (LASG/IAP). It is a spectral model truncated at R42(2.8125°long×1.66°lat) resolution and with nine vertical levels, and referred to as R42L9/LASG hereafter. It is also the new version of atmospheric component model R15L9 of the global ocean-atmosphere-land system (GOALS/LASG). A 40-year simulation in which the model is forced with the climatological monthly mean sea surface temperature is compared with the 40-year (1958-97) U.S. National Center for Environmental Prediction (NGEP) global reanalysis and the 22-year (1979-2000) Xie-Arkin monthly precipitation climatology. The mean DJF and JJA geographical distributions of precipitation, sea level pressure, 500-hPa geopotential height, 850-hPa and 200-hPa zonal wind, and other fields averaged for the last 30-year integration of the R42L9 model are analyzed. Results show that the model reproduces well the observed basic patterns, particularly precipitation over the East Asian region. Comparing the new model with R15L9/LASG, the old version with coarse resolution (nearly 7.5°long×4.5°lat), shows an obvious improvement in the simulation of regional climate, especially precipitation. The weaknesses in simulation and future improvements of the model are also discussed.展开更多
The spectral version 1.1 of the Flexible Global Ocean–atmosphere–land System （FGOALS1.1-s） model was developed in the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophys- ical Fluid Dyn...The spectral version 1.1 of the Flexible Global Ocean–atmosphere–land System （FGOALS1.1-s） model was developed in the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophys- ical Fluid Dynamics at the Institute of Atmospheric Physics （LASG/IAP）. This paper reports the major modifications to the physical parameterization package in its atmospheric component, including the radiation scheme, convection scheme, and cloud scheme. Furthermore, the simulation of the East Asian Summer Monsoon （EASM） by FGOALS1.1-s is examined, both in terms of climatological mean state and interannual variability. The results indicate that FGOALS1.1-s exhibits significant improvements in the simulation of the balance of energy at the top of the atmosphere： the net radiative energy flux at the top was 0.003 W m-2 in the 40 years fully coupled integration. The distribution of simulated sea surface temperature was also quite reasonable, without obvious climate drift. FGOALS1.1-s is also capable of capturing the major features of the climatological mean state of the EASM： major rainfall maximum centers, the annual cycle of precipitation, and the lower-level monsoon circulation flow were highly consistent with observations in the EASM region. Regarding interannual variability, simulation of the EASM leading patterns and their relationship with sea surface temperature was examined. The results show that FGOALS1.1-s can reproduce the first leading pattern of the EASM and its close relationship with the decaying phase of the ENSO. However, the model lacked the ability to capture either the second major mode of the EASM or its relationship with the developing phase of the ENSO.展开更多
Considerable spring precipitation occurs over South China(SC),a region that is adjacent to large-scale Asian topography and oceans.Its reasonable simulation is crucial for improving regional climate predictability.Thi...Considerable spring precipitation occurs over South China(SC),a region that is adjacent to large-scale Asian topography and oceans.Its reasonable simulation is crucial for improving regional climate predictability.This study investigates spring precipitation biases over SC and their possible causes in atmosphere-only and coupled Flexible Global Ocean–Atmosphere–Land System finite-volume version 3(FGOALS-f3) models with different horizontal resolutions.The performance of spring precipitation simulation over SC varies across different FGOALS-f3 model versions,with the best reproducibility in the high-resolution coupled model(25 km).In the low-resolution atmosphere-only model(100–125 km),the precipitation dry bias over SC is closely linked to overestimated surface sensible forcing over the eastern Tibetan Plateau(TP),which weakens the subtropical anticyclone over the western Pacific(SAWP) through regional circulation responses.By contrast,the high-resolution atmosphere-only model further amplifies surface thermal forcing in the Asian continents,causing intensified land–sea thermal contrast between the Southeast Asian continents and western Pacific,enhanced southerly winds and SAWP,and increased water vapor transport into SC.Meanwhile,the reduced middle–high level cold bias over 10°–30°N in the high-resolution atmosphere-only model intensifies the East Asian westerly jet and ascent over SC,leading to enhanced spring precipitation there.The high-resolution coupled model simulation not only reduces sea surface cold bias over the Bay of Bengal,thus intensifying the Indian–Burma trough and strengthening low-level water vapor transport into SC,but also enhances ascent over SC.As a result,the high-resolution coupled model better reproduces the magnitude and pattern of spring precipitation over SC than its atmosphere-only model.Compared with low-resolution models,the domain-mean spring precipitation dry bias decreases by 11.2% over SC in the high-resolution atmosphere-only model and by 35.9% in the coupled m展开更多
目前有关 El Nino( L a Nina)形成机制的讨论 ,大多是强调海气的相互作用。实际上地气相互作用过程中形成的异常气流对于 El Nino/ L a Nina的形成也是必不可少的 ,海气和地气相互作用过程应该是耦合的 ,不应该加以分离。本文综合了近...目前有关 El Nino( L a Nina)形成机制的讨论 ,大多是强调海气的相互作用。实际上地气相互作用过程中形成的异常气流对于 El Nino/ L a Nina的形成也是必不可少的 ,海气和地气相互作用过程应该是耦合的 ,不应该加以分离。本文综合了近年来我们得到的有关研究结果 ,提出了一个海气陆相互作用过程的准四年振荡过程 ,用来解释 El展开更多
文摘This paper examines the performance of an atmospheric general circulation model (AGCM) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics (LASG/IAP). It is a spectral model truncated at R42(2.8125°long×1.66°lat) resolution and with nine vertical levels, and referred to as R42L9/LASG hereafter. It is also the new version of atmospheric component model R15L9 of the global ocean-atmosphere-land system (GOALS/LASG). A 40-year simulation in which the model is forced with the climatological monthly mean sea surface temperature is compared with the 40-year (1958-97) U.S. National Center for Environmental Prediction (NGEP) global reanalysis and the 22-year (1979-2000) Xie-Arkin monthly precipitation climatology. The mean DJF and JJA geographical distributions of precipitation, sea level pressure, 500-hPa geopotential height, 850-hPa and 200-hPa zonal wind, and other fields averaged for the last 30-year integration of the R42L9 model are analyzed. Results show that the model reproduces well the observed basic patterns, particularly precipitation over the East Asian region. Comparing the new model with R15L9/LASG, the old version with coarse resolution (nearly 7.5°long×4.5°lat), shows an obvious improvement in the simulation of regional climate, especially precipitation. The weaknesses in simulation and future improvements of the model are also discussed.
基金supported by the Na-tional Natural Science Foundation of China (40890054,40805038)the 973 Program of China (2010CB950404)+2 种基金the R&D Special Fund for Public Welfare Industry (meteorol-ogy) (GYHY200806006)the Chinese Academy of Sciences(KZCX2-YW-Q11-04)the National Science & Tech-nology Pillar Program of China (2007BAC29B03).
文摘The spectral version 1.1 of the Flexible Global Ocean–atmosphere–land System （FGOALS1.1-s） model was developed in the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophys- ical Fluid Dynamics at the Institute of Atmospheric Physics （LASG/IAP）. This paper reports the major modifications to the physical parameterization package in its atmospheric component, including the radiation scheme, convection scheme, and cloud scheme. Furthermore, the simulation of the East Asian Summer Monsoon （EASM） by FGOALS1.1-s is examined, both in terms of climatological mean state and interannual variability. The results indicate that FGOALS1.1-s exhibits significant improvements in the simulation of the balance of energy at the top of the atmosphere： the net radiative energy flux at the top was 0.003 W m-2 in the 40 years fully coupled integration. The distribution of simulated sea surface temperature was also quite reasonable, without obvious climate drift. FGOALS1.1-s is also capable of capturing the major features of the climatological mean state of the EASM： major rainfall maximum centers, the annual cycle of precipitation, and the lower-level monsoon circulation flow were highly consistent with observations in the EASM region. Regarding interannual variability, simulation of the EASM leading patterns and their relationship with sea surface temperature was examined. The results show that FGOALS1.1-s can reproduce the first leading pattern of the EASM and its close relationship with the decaying phase of the ENSO. However, the model lacked the ability to capture either the second major mode of the EASM or its relationship with the developing phase of the ENSO.
基金Supported by the National Key Research and Development Program of China (2022YFF0802003)National Natural Science Foundation of China (42288101,42275026,and 41975109)+2 种基金Natural Science Foundation of Yunnan Province (202301AV070001)Yunnan University Graduate Research and Innovation Fund (KC-22221894)National Key Scientific and Technological Infrastructure Project of China “Earth System Science Numerical Simulator Facility”(EarthLab)。
文摘Considerable spring precipitation occurs over South China(SC),a region that is adjacent to large-scale Asian topography and oceans.Its reasonable simulation is crucial for improving regional climate predictability.This study investigates spring precipitation biases over SC and their possible causes in atmosphere-only and coupled Flexible Global Ocean–Atmosphere–Land System finite-volume version 3(FGOALS-f3) models with different horizontal resolutions.The performance of spring precipitation simulation over SC varies across different FGOALS-f3 model versions,with the best reproducibility in the high-resolution coupled model(25 km).In the low-resolution atmosphere-only model(100–125 km),the precipitation dry bias over SC is closely linked to overestimated surface sensible forcing over the eastern Tibetan Plateau(TP),which weakens the subtropical anticyclone over the western Pacific(SAWP) through regional circulation responses.By contrast,the high-resolution atmosphere-only model further amplifies surface thermal forcing in the Asian continents,causing intensified land–sea thermal contrast between the Southeast Asian continents and western Pacific,enhanced southerly winds and SAWP,and increased water vapor transport into SC.Meanwhile,the reduced middle–high level cold bias over 10°–30°N in the high-resolution atmosphere-only model intensifies the East Asian westerly jet and ascent over SC,leading to enhanced spring precipitation there.The high-resolution coupled model simulation not only reduces sea surface cold bias over the Bay of Bengal,thus intensifying the Indian–Burma trough and strengthening low-level water vapor transport into SC,but also enhances ascent over SC.As a result,the high-resolution coupled model better reproduces the magnitude and pattern of spring precipitation over SC than its atmosphere-only model.Compared with low-resolution models,the domain-mean spring precipitation dry bias decreases by 11.2% over SC in the high-resolution atmosphere-only model and by 35.9% in the coupled m
文摘目前有关 El Nino( L a Nina)形成机制的讨论 ,大多是强调海气的相互作用。实际上地气相互作用过程中形成的异常气流对于 El Nino/ L a Nina的形成也是必不可少的 ,海气和地气相互作用过程应该是耦合的 ,不应该加以分离。本文综合了近年来我们得到的有关研究结果 ,提出了一个海气陆相互作用过程的准四年振荡过程 ,用来解释 El
