CAJ | 학술논문

利用 ERA-Interim 再分析资料、NOAA 海温资料、CMAP 格点降水资料和中国气象站降水资料，通过合成、相关和回归分析等方法研究了1979—2012年东亚夏季风强度与其先兆信号的关系，并分析了热带海温异常的可能影响。研究表明：东亚夏季风先兆指数反映了2月200 hPa 纬向风距平的主要模态特征（EOF1），前冬热带中东太平洋海温偏低（高），2月亚洲地区西风急流位置偏北（偏南），东亚夏季风先兆指数偏强（弱）。前期热带海温异常对东亚夏季风强度有明显影响，前冬热带中东太平洋海温偏低（高）有利于东亚夏季风偏强（弱）。2月亚洲中纬度地区纬向风异常特征在春季不能持续，先兆信号与东亚夏季风强度的联系主要源自热带海洋。
이용 ERA-Interim 재분석자료、NOAA 해온자료、CMAP 격점강수자료화중국기상참강수자료，통과합성、상관화회귀분석등방법연구료1979—2012년동아하계풍강도여기선조신호적관계，병분석료열대해온이상적가능영향。연구표명：동아하계풍선조지수반영료2월200 hPa 위향풍거평적주요모태특정（EOF1），전동열대중동태평양해온편저（고），2월아주지구서풍급류위치편북（편남），동아하계풍선조지수편강（약）。전기열대해온이상대동아하계풍강도유명현영향，전동열대중동태평양해온편저（고）유리우동아하계풍편강（약）。2월아주중위도지구위향풍이상특정재춘계불능지속，선조신호여동아하계풍강도적련계주요원자열대해양。
The strength of the East Asian Summer Monsoon (EASM)is closely connected to the summer main rainfall belt in China.The precursor index defined by the difference of zonal wind anomaly at 200 hPa be-tween the middle latitude in Asia and eastern Pacific in February is well indicative to the strength of EASM,which is an important predicting factors in flood season.The potential mechanism of precursor signal influencing the EASM is proposed by changing the surface characteristics in South Asia continent, but it is unclear whether the atmospheric circulation anomaly in February persists in the following seasons over middle latitude region.In addition,a further investigation is needed about the surface anomaly varia-tion over South Asia in winter-spring seasons.ERA-Interim reanalysis data,NOAA sea surface data, gridded CMAP precipitation data and precipitation observations over China are used.By composite,corre-lation and regression analysis approaches,the difference of wind in middle latitude over Eurasia,sea sur-face temperature (SST)in tropics and thermal condition in South Asia continent in previous winter-spring seasons in various strength EASM years are analyzed.Results indicate that tropical SST is the physical connection of accordant variations between the strength of EASM and its precursor. <br> Results show that the precursor signal of EASM captures the primary feature for the first mode of em-pirical orthogonal function (EOF1)of zonal wind anomaly at 200 hPa over the Asia and Pacific in February. The EOF1 mode is related to SST in the central and eastern Pacific.In the previous winter,the SST is be-low (above)normal in the central and eastern Pacific,which is conducive to a northward (southward)shift of westerly jet over the Asia in February.The zonal wind anomaly at 200 hPa exhibits meridional positive-negative-positive (negative-positive-negative)pattern,and the precursor index is stronger (weaker)than normal.In summer,the negative (positive)SST anomaly occurs in the vicinity of Indian Ocean and South China Sea,which results in an increasing (decreasing)difference between ocean and land and stronger (weaker)Indian Summer Monsoon.Meanwhile,the western Pacific subtropical high (WPSH)is weaker (stronger)than normal,and the EASM is stronger (weaker)than normal.The anomalous feature of zonal wind in the middle latitude of the Asia in February is hardly to persist in spring.The physical connection between EASM and its precursor mainly derives from the tropical ocean.