摘要
利用NCEP/NCAR全球再分析资料和中国夏季站点资料,采用相关分析、合成分析以及线性回归方法,找到了与澳大利亚高压(下称澳高)显著相关的海温关键区,并分析了此关键区海温异常的年际变化与中国夏季气候异常的联系。结果表明:海洋性大陆区域附近海区是与澳高变化相关的海温异常关键区,其与澳高指数的时间序列相关系数高达-0.64。在不考虑ENSO的影响时,关键区海温的年际变化与中国东部地区夏季气候存在密切联系,即当澳高指数偏强(偏弱)时,海洋性大陆区域附近的海温偏低(偏高),辽宁、吉林大部分以及江淮东部地区夏季降水较常年偏少(偏多),江南地区降水偏多(偏少)。关键区海温对中国夏季气候的可能影响途径是:印度尼西亚附近海温负异常时,低层风场异常辐散,辐散场作为涡度源在南海西太平洋地区激发类似EAP或P—J型波列,在30°N以南形成异常气旋环流,30°N-50°N形成异常反气旋环流,50°N以北形成异常气旋环流,这样的异常分布有利于"南涝北旱"降水格局的形成。另外,降水异常时气温亦存在显著异常,我国东部气温为异常的"南低北高"分布。当海洋性大陆区域附近的海温为正异常时,情况相反。
By using the NCEP/NCAR reanalysis and in situ station data of precipitation and surface air temperature in China,we have investigated influences of the sea surface temperature anomalies（SSTA） in Maritime Continent（MC） region on the summer climate of China in association with variations of Australian High（AH）.It is found that large SSTA occur in Maritime Continent region when Australian High changes on inter-annual timescales.The Indonesia region is hence fixed as the key area for SST anomalies with which the composite analyses are performed of circulation anomalies along with the summer climate variations in China.The SSTA in key area is highly correlated with the AH index;the correlation coefficient is found to be-0.64.By regressing ENSO signal out,the SSTA variations in key area is found to have close relations with summer climate anomalies in the eastern part of China.When AH is stronger（weaker） than normal,the SST around Indonesia is lower（higher） than normal.Correspondingly,the summer precipitation is simultaneously less（more） than normal in Jianghuai region and most areas of Liaoning and Jilin provinces whereas more（less） precipitation in Yangtze River regions.Meanwhile,summer temperature is higher（lower） in most areas of Liaoning and Jilin province,while it is lower（higher） than normal in Yangtze River regions.The SSTA in key area influence summer climate in eastern China in following ways.When SSTA in area Indonesia is negative,winds in lower troposphere anomalously diverge.This divergence works as the anomalous vorticity source,exciting an EAP/P- J wavetrain pattern from South China Sea northeastward into the west Pacific.There is an anomalous cyclonic circulation in region south of 30°N and an anti- cyclonic circulation in region between 30°N and 50°N.Another anomalous cyclonic circulation exists in region north of 50 °N.This circulation pattern featured by anomalous cycloneanticyclone-cyclone from south to north facilitates the western Pacific subtropical high to
出处
《高原气象》
CSCD
北大核心
2016年第1期188-197,共10页
Plateau Meteorology
基金
国家自然科学基金项目(41330425)
公益性行业(气象)科研专项(GYHY201406024)
