Two Types of El Nio-related Southern Oscillation and Their Diferent Impacts on Global Land Precipitation  

作　　者：徐康 祝从文 何金海 

机构地区：[1]Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science and Technology [2]Institute of Climate Systems, Chinese Academy of Meteorological Sciences [3]State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2013年第6期1743-1757,共15页大气科学进展（英文版）

基　　金：jointly supported by the National Natural Science Foundation of China(Grant No.41221064);the 973 Program of China(Grant No.2012CB417403);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05090408);the key program of the Chinese Academy of Meteorological Science(Grant No.2010Z003 and 2013Z002);the Research and Innovation Project for College Graduates of Jiangsu Province(Grant No.CXLX11 0618)

摘　　要：The contrast between the eastern and central responses of zonal and vertical circulation in the Pacific （EP- and CP-） E1 Nino is observed in the different tropics. To measure the different responses of the atmo- spheric circulation to the two types of E1 Nino, an eastern and a central Pacific southern oscillation index （EP- and CP-SOI） are defined based on the air-sea coupled relationship between eddy sea level pressure and sea surface temperature. Analyses suggest that while the EP-SOI exhibits variability on an interannual （2- 7-yr） time scale, decadal （10-15-yr） variations in the CP-SOI are more dominant; both are strongly coupled with their respective EP- and CP-E1 Nino patterns. Composite analysis suggests that, during EP-ENSO, the Walker circulation exhibits a dipole structure in the lower-level （850 hPa） and upper-level （200 hPa） velocity potential anomalies and exhibits a signal cell over the Pacific. In the case of CP-ENSO, however, the Walker circulation shows a tripole structure and exhibits double cells over the Pacific. In addition, the two types of ENSO events show opposite impacts on global land precipitation in the boreal winter and spring seasons. For example, seasonal precipitation across China's Mainland exhibits an opposite relationship with the EP- and CP-ENSO during winter and spring, but the rainfall over the lower reaches of the Yangtze River and South China shows an opposite relationship during the rest of the seasons. Therefore, the different relationships between rainfall and EP- and CP-ENSO should be carefully considered when predicting seasonal rainfall in the East Asian monsoon regions.The contrast between the eastern and central responses of zonal and vertical circulation in the Pacific （EP- and CP-） E1 Nino is observed in the different tropics. To measure the different responses of the atmo- spheric circulation to the two types of E1 Nino, an eastern and a central Pacific southern oscillation index （EP- and CP-SOI） are defined based on the air-sea coupled relationship between eddy sea level pressure and sea surface temperature. Analyses suggest that while the EP-SOI exhibits variability on an interannual （2- 7-yr） time scale, decadal （10-15-yr） variations in the CP-SOI are more dominant; both are strongly coupled with their respective EP- and CP-E1 Nino patterns. Composite analysis suggests that, during EP-ENSO, the Walker circulation exhibits a dipole structure in the lower-level （850 hPa） and upper-level （200 hPa） velocity potential anomalies and exhibits a signal cell over the Pacific. In the case of CP-ENSO, however, the Walker circulation shows a tripole structure and exhibits double cells over the Pacific. In addition, the two types of ENSO events show opposite impacts on global land precipitation in the boreal winter and spring seasons. For example, seasonal precipitation across China's Mainland exhibits an opposite relationship with the EP- and CP-ENSO during winter and spring, but the rainfall over the lower reaches of the Yangtze River and South China shows an opposite relationship during the rest of the seasons. Therefore, the different relationships between rainfall and EP- and CP-ENSO should be carefully considered when predicting seasonal rainfall in the East Asian monsoon regions.

关 键 词：Southern Oscillation eddy sea level pressure eastern and central Pacific ENSO Walker cir- culation precipitation anomalies 

分 类 号：P426.615[天文地球—大气科学及气象学]