In this paper, results from a pilot study for the South China Sea Monsoon Experiment are reported. Based on analyses of 9 years of pentad and monthly mean data, the climatology of subseasonal features and interannual ...In this paper, results from a pilot study for the South China Sea Monsoon Experiment are reported. Based on analyses of 9 years of pentad and monthly mean data, the climatology of subseasonal features and interannual variability of the Southeast Asian monsoon (SEAM) are documented. The present analysis is focused on the sudden onset of the South China Sea monsoon and its relation to the atmospheric and oceanic processes on the entire Asian monsoon region. \ \ It is found that the onset of the SEAM occurs around mid-May, signaling the earliest stage of the entire Asian summer monsoon system. The establishment of monsoon rainfall over the South China Sea is abrupt, being accompanied by substantial changes in the large scale atmospheric circulation and sea surface temperature in the adjacent oceans. The onset and fluctuations of SEAM involve the interaction and metamorphosis of the large scale convection over the Indo-China, the South China Sea and the southern Bay of Bengal. Results show that the onset time of the SEAM differs greatly from one year to another. The delayed (advanced) onset of the monsoon may be related to basin-wide warm (cold) events of the Pacific and Indian Oceans. We also present evidence showing that the SEAM fluctuations in May may foreshadow the development of the full-scale Asian summer monsoon during the subsequent months.展开更多
Using observation and reanalysis data throughout 1961-1990, the East Asian surface air temperature, precipitation and sea level pressure climatology as simulated by seven fully coupled atmosphere-ocean models, namely ...Using observation and reanalysis data throughout 1961-1990, the East Asian surface air temperature, precipitation and sea level pressure climatology as simulated by seven fully coupled atmosphere-ocean models, namely CCSR/NIES, CGCM2, CSIRO-Mk2, ECHAM4/OPYC3, GFDL-R30, HadCM3, and NCAR-PCM, are systematically evaluated in this study. It is indicated that the above models can successfully reproduce the annual and seasonal surface air temperature and precipitation climatology in East Asia, with relatively good performance for boreal autumn and annual mean. The models' ability to simulate surface air temperature is more reliable than precipitation. In addition, the models can dependably capture the geographical distribution pattern of annual, boreal winter, spring and autumn sea level pressure in East Asia. In contrast, relatively large simulation errors are displayed when simulated boreal summer sea level pressure is compared with reanalysis data in East Asia. It is revealed that the simulation errors for surface air temperature, precipitation and sea level pressure are generally large over and around the Tibetan Plateau. No individual model is best in every aspect. As a whole, the ECHAM4/OPYC3 and HadCM3 performances are much better, whereas the CGCM2 is relatively poorer in East Asia. Additionally, the seven-model ensemble mean usually shows a relatively high reliability.展开更多
We compare the ability of coupled global climate models from the phases 5 and 6 of the Coupled Model Intercomparison Project(CMIP5 and CMIP6,respectively)in simulating the temperature and precipitation climatology and...We compare the ability of coupled global climate models from the phases 5 and 6 of the Coupled Model Intercomparison Project(CMIP5 and CMIP6,respectively)in simulating the temperature and precipitation climatology and interannual variability over China for the period 1961–2005 and the climatological East Asian monsoon for the period 1979–2005.All 92 models are able to simulate the geographical distribution of the above variables reasonably well.Compared with earlier CMIP5 models,current CMIP6 models have nationally weaker cold biases,a similar nationwide overestimation of precipitation and a weaker underestimation of the southeast–northwest precipitation gradient,a comparable overestimation of the spatial variability of the interannual variability,and a similar underestimation of the strength of winter monsoon over northern Asia.Pairwise comparison indicates that models have improved from CMIP5 to CMIP6 for climatological temperature and precipitation and winter monsoon but display little improvement for the interannual temperature and precipitation variability and summer monsoon.The ability of models relates to their horizontal resolutions in certain aspects.Both the multi-model arithmetic mean and median display similar skills and outperform most of the individual models in all considered aspects.展开更多
文摘In this paper, results from a pilot study for the South China Sea Monsoon Experiment are reported. Based on analyses of 9 years of pentad and monthly mean data, the climatology of subseasonal features and interannual variability of the Southeast Asian monsoon (SEAM) are documented. The present analysis is focused on the sudden onset of the South China Sea monsoon and its relation to the atmospheric and oceanic processes on the entire Asian monsoon region. \ \ It is found that the onset of the SEAM occurs around mid-May, signaling the earliest stage of the entire Asian summer monsoon system. The establishment of monsoon rainfall over the South China Sea is abrupt, being accompanied by substantial changes in the large scale atmospheric circulation and sea surface temperature in the adjacent oceans. The onset and fluctuations of SEAM involve the interaction and metamorphosis of the large scale convection over the Indo-China, the South China Sea and the southern Bay of Bengal. Results show that the onset time of the SEAM differs greatly from one year to another. The delayed (advanced) onset of the monsoon may be related to basin-wide warm (cold) events of the Pacific and Indian Oceans. We also present evidence showing that the SEAM fluctuations in May may foreshadow the development of the full-scale Asian summer monsoon during the subsequent months.
基金This research was jointly supported by the Chinese Academy of Sciences(CAS)under Grant No.KZCX3-SW-221by the National Natural Science Foundation of China under Grant No.40405015+1 种基金by the Chinese Ministry of Science and Technology under Grant No.2001BA611B(part 1)by the CAS“Hundred Talent Project"funding awarded to Gao Yongqi.
文摘Using observation and reanalysis data throughout 1961-1990, the East Asian surface air temperature, precipitation and sea level pressure climatology as simulated by seven fully coupled atmosphere-ocean models, namely CCSR/NIES, CGCM2, CSIRO-Mk2, ECHAM4/OPYC3, GFDL-R30, HadCM3, and NCAR-PCM, are systematically evaluated in this study. It is indicated that the above models can successfully reproduce the annual and seasonal surface air temperature and precipitation climatology in East Asia, with relatively good performance for boreal autumn and annual mean. The models' ability to simulate surface air temperature is more reliable than precipitation. In addition, the models can dependably capture the geographical distribution pattern of annual, boreal winter, spring and autumn sea level pressure in East Asia. In contrast, relatively large simulation errors are displayed when simulated boreal summer sea level pressure is compared with reanalysis data in East Asia. It is revealed that the simulation errors for surface air temperature, precipitation and sea level pressure are generally large over and around the Tibetan Plateau. No individual model is best in every aspect. As a whole, the ECHAM4/OPYC3 and HadCM3 performances are much better, whereas the CGCM2 is relatively poorer in East Asia. Additionally, the seven-model ensemble mean usually shows a relatively high reliability.
文摘We compare the ability of coupled global climate models from the phases 5 and 6 of the Coupled Model Intercomparison Project(CMIP5 and CMIP6,respectively)in simulating the temperature and precipitation climatology and interannual variability over China for the period 1961–2005 and the climatological East Asian monsoon for the period 1979–2005.All 92 models are able to simulate the geographical distribution of the above variables reasonably well.Compared with earlier CMIP5 models,current CMIP6 models have nationally weaker cold biases,a similar nationwide overestimation of precipitation and a weaker underestimation of the southeast–northwest precipitation gradient,a comparable overestimation of the spatial variability of the interannual variability,and a similar underestimation of the strength of winter monsoon over northern Asia.Pairwise comparison indicates that models have improved from CMIP5 to CMIP6 for climatological temperature and precipitation and winter monsoon but display little improvement for the interannual temperature and precipitation variability and summer monsoon.The ability of models relates to their horizontal resolutions in certain aspects.Both the multi-model arithmetic mean and median display similar skills and outperform most of the individual models in all considered aspects.
