The impact of strong(weak) intraseasonal oscillation(ISO) over South China Sea(SCS) and South Asia(SA)in summer on the SCS and SA summer monsoon and the summer rainfall in Eastern China are studied by using the NCEP-N...The impact of strong(weak) intraseasonal oscillation(ISO) over South China Sea(SCS) and South Asia(SA)in summer on the SCS and SA summer monsoon and the summer rainfall in Eastern China are studied by using the NCEP-NCAR analysis data and the rainfall data of 160 stations in China from 1961 to 2010.It is found that the impacts are significantly different in different months of summer.The study shows that in June and July cyclonic(anticyclonic) atmospheric circulation over SCS and SA corresponds to strong(weak) ISO over SCS.In August,however,strong(weak) ISO over SCS still corresponds to cyclonic(anticyclonic) atmospheric circulation over SA.In June and August cyclonic(anticyclonic) atmospheric circulation over South Asia corresponds to strong(weak) ISO over SA while a strong(weak) ISO corresponds to anticyclonic(cyclonic) atmospheric circulation over SA in July.Besides,in June the strong(weak) ISO over SA corresponds to cyclonic(anticyclonic) atmospheric circulation over SCS,while in July and August the atmospheric circulation is in the same phase regardless of whether the ISO over SA is strong or weak.The impacts of the strong(weak)ISO over SCS on the rainfall of eastern China are similar in June and July,which favors less(more) rainfall in Yangtze-Huaihe Rivers basin but sufficient(deficient) rainfall in the south of Yangtze River.However,the impacts are not so apparent in August.In South Asia,the strong(weak) ISO in July results in less(more)rainfall in the south of Yangtze River but sufficient(deficient) rainfall in Yangtze-Huaihe Rivers basin.The influence on the rainfall in eastern China in June and August is not as significant as in July.展开更多
基金National Fundamental Research 973 Program of China(2010CB950401)
文摘The impact of strong(weak) intraseasonal oscillation(ISO) over South China Sea(SCS) and South Asia(SA)in summer on the SCS and SA summer monsoon and the summer rainfall in Eastern China are studied by using the NCEP-NCAR analysis data and the rainfall data of 160 stations in China from 1961 to 2010.It is found that the impacts are significantly different in different months of summer.The study shows that in June and July cyclonic(anticyclonic) atmospheric circulation over SCS and SA corresponds to strong(weak) ISO over SCS.In August,however,strong(weak) ISO over SCS still corresponds to cyclonic(anticyclonic) atmospheric circulation over SA.In June and August cyclonic(anticyclonic) atmospheric circulation over South Asia corresponds to strong(weak) ISO over SA while a strong(weak) ISO corresponds to anticyclonic(cyclonic) atmospheric circulation over SA in July.Besides,in June the strong(weak) ISO over SA corresponds to cyclonic(anticyclonic) atmospheric circulation over SCS,while in July and August the atmospheric circulation is in the same phase regardless of whether the ISO over SA is strong or weak.The impacts of the strong(weak)ISO over SCS on the rainfall of eastern China are similar in June and July,which favors less(more) rainfall in Yangtze-Huaihe Rivers basin but sufficient(deficient) rainfall in the south of Yangtze River.However,the impacts are not so apparent in August.In South Asia,the strong(weak) ISO in July results in less(more)rainfall in the south of Yangtze River but sufficient(deficient) rainfall in Yangtze-Huaihe Rivers basin.The influence on the rainfall in eastern China in June and August is not as significant as in July.
