Decadal changes of the wintertime tropical tropospheric temperature and their influences on the extratropical climate  

北半球冬季热带对流层温度的年代际变化及其气候影响(英文)

作　　者：张嘉莹 王林 杨崧 陈文 皇甫静亮 

机构地区：[1]Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Center for Monsoon System Research, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences [4]Institute of Earth Climate and Environment System,School of Atmospheric Sciences, Sun Yat-sen University

出　　处：《Science Bulletin》2016年第9期737-744,共8页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(41422501;41230527);the National Key Scientific Research Plan of China(2014CB953904)

摘　　要：A decadal change of the tropical tropospheric temperature （TT） was identified to occur in the winter of 1997. Compared with that in the former period （1979-1996）, the wintertime TT was significantly high over most of the tropical regions except over the tropical eastern Pacific during the latter period （1997-2014） because the sea surface temperature （SST） exhibited a decadal La Nifia-like pattern after 1997. The warm SST anomalies over the tropical western Pacific facilitated enhanced precipitation and increased heat release to the tropical atmosphere, leading to a warmer tropical tropo- sphere in the latter period. In addition to the mean TT values, the interannual variability of the tropical TT changed in 1997. The leading mode of the tropical TT explained 72.9 % of the total variance in the former period. It led to significant warming over midlatitude North America via a Pacific-North America （PNA）-like wave train and off the coast of East Asia via an anomalous lower-tropospheric anticyclone around the Philippines. The mode remained a similar pattern but explained 85.4 % of the total variance in the latter period, and its location was slightly westward-shifted compared with that in the former period. As a result, the structure of the PNA-like wave train changed, leading to anomalous warming over northwestern North America and enhanced precipitation over the southern North America. Meanwhile, the anomalous lower- tropospheric anticyclone around the Philippines shifted westward, leading to increased precipitation and regional warming over East Asia. The decadal changes of the leading mode of the tropical TT and its influences on the extratropical climate can be attributed to the changes of the tropical SST variability.热带对流层温度(TT)可以反映热带大气受到的非绝热加热.本研究表明,北半球冬季热带TT在1997年发生了年代际突变:一方面,受年代际La Ni?a型海温和降水的影响,热带TT的平均值在1997年后有显著增加,这表明热带大气受到的非绝热加热有年代际增强;另一方面,热带TT年际变率主模态的空间型和解释方差在1997年后有显著变化,从而导致在年际变化尺度上由热带TT引起的气温、降水异常在东亚和北美地区有显著改变.

关 键 词：Tropospheric temperature Sea surfacetemperature Decadal shift Interannual variabilityEast Asia North America 

分 类 号：P461[天文地球—大气科学及气象学]