Based on time series and linear trend analysis, the authors evaluated the performance of the fourth gen- eration atmospheric general circulation model developed at the Institute of Atmospheric Physics, Chinese Academy...Based on time series and linear trend analysis, the authors evaluated the performance of the fourth gen- eration atmospheric general circulation model developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences （IAP AGCM4.0）, in simulating surface air temperature （SAT） during the twentieth century over China and the globe. The numerical experiment is con- ducted by driving the model with the observed sea surface temperature and sea ice. It is shown that IAP AGCM4.0 can simulate the warming trend of the global SAT, with the major wanning regions in the high latitudes of the Northern Hemisphere and the mid-latitudes of the South- ern Hemisphere. While the simulated trend over the whole globe is close to the observation, the model trader- estimates the observed trend over the continents. More- over, the model simulates the spatial distribution of SAT in China, with a bias of approximately -2℃ in eastern China, but with a more serious bias in western China. Compared with the global mean, however, the correlation coefficient between the simulation and observation in China is significantly lower, indicating that there is large uncertainty in simulating regional climate change.展开更多
Based on a 30-year Atmospheric Model Intercomparison Project(AMIP) simulation using IAP AGCM4.0, the relationship between the East Asian subtropical westerly jet(EASWJ) and summer precipitation over East Asia has been...Based on a 30-year Atmospheric Model Intercomparison Project(AMIP) simulation using IAP AGCM4.0, the relationship between the East Asian subtropical westerly jet(EASWJ) and summer precipitation over East Asia has been investigated, and compared with observation. It was found the meridional displacement of the EASWJ has a closer relationship with the precipitation over East Asia both from model simulation and observation, with an anomalous southward shift of EASWJ being conducive to rainfall over the Yangtze-Huaihe River Valley(YHRV), and an anomalous northward shift resulting in less rainfall over the YHRV. However, the simulated precipitation anomalies were found to be weaker than observed from the composite analysis, and this would be related to the weakly reproduced mid-upper-level convergence in the mid-high latitudes and ascending motion in the lower latitudes.展开更多
This paper focuses on the relationship between the phase transition of the Pacific decadal oscillation （PDO） and decadal variation of the East Asian summer monsoon （EASM） in the twentieth century. The first transi...This paper focuses on the relationship between the phase transition of the Pacific decadal oscillation （PDO） and decadal variation of the East Asian summer monsoon （EASM） in the twentieth century. The first transition occurred in the 1940s, with an enhanced SST in the North Pacific and reduced SST in the tropical eastern Pacific and South Indian Ocean. In agreement with these SST changes, a higher SLP was found in most parts of the Pacific, while a lower SLP was found in the North Pacific and most parts of the Indian Ocean. In this case, the EASM was largely enhanced with a southerly anomaly in the lower troposphere along the east coast of China. Correspondingly, there was less rainfall in the Yangtze River valley and more rainfall in northern and southern China. An opposite change was found when the PDO reversed its phase in the late 1970s. In the tropical Indian Ocean and western Pacific, however, the SST was enhanced in both the 1940s and 1970s. As a result, the western Pacific subtropical high （WPSH） tended to extend westward with a larger magnitude in the 1970s. The major features were reasonably reproduced by an atmospheric general circulation model （IAP AGCM4.0） prescribed with observed SST and sea ice. On the other hand, the westward extension of the WPSH was exaggerated in the 1970s, while it was underestimated in the 1940s. Besides, the spatial pattern of the simulated summer rainfall in eastern China tended to shift southward compared with the observation.展开更多
基金supported by the Strategic Priority Research Program-Climate Change: Carbon Budget and Related Issues of the Chinese Academy of Sciences (Grant No. XDA05110201)the Development and Validation of High Resolution Climate System Model of the National Basic Research Program of China (Grant No.2010CB951901)
文摘Based on time series and linear trend analysis, the authors evaluated the performance of the fourth gen- eration atmospheric general circulation model developed at the Institute of Atmospheric Physics, Chinese Academy of Sciences （IAP AGCM4.0）, in simulating surface air temperature （SAT） during the twentieth century over China and the globe. The numerical experiment is con- ducted by driving the model with the observed sea surface temperature and sea ice. It is shown that IAP AGCM4.0 can simulate the warming trend of the global SAT, with the major wanning regions in the high latitudes of the Northern Hemisphere and the mid-latitudes of the South- ern Hemisphere. While the simulated trend over the whole globe is close to the observation, the model trader- estimates the observed trend over the continents. More- over, the model simulates the spatial distribution of SAT in China, with a bias of approximately -2℃ in eastern China, but with a more serious bias in western China. Compared with the global mean, however, the correlation coefficient between the simulation and observation in China is significantly lower, indicating that there is large uncertainty in simulating regional climate change.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05110202)the National Natural Science Foundation of China (Grant Nos. 41175073 and U1133603)
文摘Based on a 30-year Atmospheric Model Intercomparison Project(AMIP) simulation using IAP AGCM4.0, the relationship between the East Asian subtropical westerly jet(EASWJ) and summer precipitation over East Asia has been investigated, and compared with observation. It was found the meridional displacement of the EASWJ has a closer relationship with the precipitation over East Asia both from model simulation and observation, with an anomalous southward shift of EASWJ being conducive to rainfall over the Yangtze-Huaihe River Valley(YHRV), and an anomalous northward shift resulting in less rainfall over the YHRV. However, the simulated precipitation anomalies were found to be weaker than observed from the composite analysis, and this would be related to the weakly reproduced mid-upper-level convergence in the mid-high latitudes and ascending motion in the lower latitudes.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05110201)the National Natural Science Foundation of China(Grant No.41475052)
文摘This paper focuses on the relationship between the phase transition of the Pacific decadal oscillation （PDO） and decadal variation of the East Asian summer monsoon （EASM） in the twentieth century. The first transition occurred in the 1940s, with an enhanced SST in the North Pacific and reduced SST in the tropical eastern Pacific and South Indian Ocean. In agreement with these SST changes, a higher SLP was found in most parts of the Pacific, while a lower SLP was found in the North Pacific and most parts of the Indian Ocean. In this case, the EASM was largely enhanced with a southerly anomaly in the lower troposphere along the east coast of China. Correspondingly, there was less rainfall in the Yangtze River valley and more rainfall in northern and southern China. An opposite change was found when the PDO reversed its phase in the late 1970s. In the tropical Indian Ocean and western Pacific, however, the SST was enhanced in both the 1940s and 1970s. As a result, the western Pacific subtropical high （WPSH） tended to extend westward with a larger magnitude in the 1970s. The major features were reasonably reproduced by an atmospheric general circulation model （IAP AGCM4.0） prescribed with observed SST and sea ice. On the other hand, the westward extension of the WPSH was exaggerated in the 1970s, while it was underestimated in the 1940s. Besides, the spatial pattern of the simulated summer rainfall in eastern China tended to shift southward compared with the observation.
