CAJ | 학술논문

本文基于1958至2002年的ERA-40月平均再分析资料，利用年际增量方法分析了春季北极涛动（Arctic Oscillation，简称AO）与我国夏季长江流域地表气温的关系。结果表明，在扣除前期冬季ENSO影响后，5月AO指数与8月长江流域地表气温存在显著正相关。通过回归分析发现，5月AO可通过影响中低纬度的海气相互作用进而影响8月长江流域地表气温。当5月AO处于正位相时，在（10°～15°N）及赤道附近产生异常下沉气流，对应着西太平洋局地Hadley环流减弱，对流层底层出现了异常的反气旋性辐散气流。与之对应，赤道西太平洋地区出现了显著的东风异常。由于该东风异常位于5月气候平均的局地海表面温度（SST）极大值中心位置上，该东风异常可通过平流作用使得高海温不断地向西堆积，最终造成赤道西太平洋SST出现显著正异常。当该SST正异常持续至8月时，它通过 Gill 响应（Gill，1980）在其西北侧激发出气旋性异常环流，它有利于西太平洋副热带高压在我国长江流域的维持，进而造成长江流域地表气温正异常。反之，则相反。
본문기우1958지2002년적ERA-40월평균재분석자료，이용년제증량방법분석료춘계북겁도동（Arctic Oscillation，간칭AO）여아국하계장강류역지표기온적관계。결과표명，재구제전기동계ENSO영향후，5월AO지수여8월장강류역지표기온존재현저정상관。통과회귀분석발현，5월AO가통과영향중저위도적해기상호작용진이영향8월장강류역지표기온。당5월AO처우정위상시，재（10°～15°N）급적도부근산생이상하침기류，대응착서태평양국지Hadley배류감약，대류층저층출현료이상적반기선성복산기류。여지대응，적도서태평양지구출현료현저적동풍이상。유우해동풍이상위우5월기후평균적국지해표면온도（SST）겁대치중심위치상，해동풍이상가통과평류작용사득고해온불단지향서퇴적，최종조성적도서태평양SST출현현저정이상。당해SST정이상지속지8월시，타통과 Gill 향응（Gill，1980）재기서북측격발출기선성이상배류，타유리우서태평양부열대고압재아국장강류역적유지，진이조성장강류역지표기온정이상。반지，칙상반。
AbstractBased on ERA-40 monthly mean reanalysis data over the period 1958–2002, this paper studies the relationship between the spring Arctic Oscillation (AO) and the summer surface air temperature (SAT) over the Yangtze River valley by adopting the year-to-year increment approach. The winter ENSO signal is filtered out in advance. Results show that the AO in May is significantly and positively correlated with the SAT over the Yangtze River valley in August. The possible physical mechanism for this relationship is investigated by means of regression analysis. The air–ocean interaction over the middle and low latitudes might play an important role. Following a stronger positive AO in May, an anomalous subsidence flow appears over the region 10°–15°N and the Equator. At the same time, Hadley circulation over the western Pacific becomes weaker, leading to an anomalous anticyclonic divergent flow in the lower troposphere. Accordingly, significant easterly anomalies appear over the equatorial western Pacific. Since the easterly anomalies are located at the local maximum center of the climatological mean sea surface temperature (SST), the warm SSTs pile up to the west via advection, inducing the above-normal SST over the equatorial western Pacific. The positive SST anomalies persist from May to August. This can trigger an anomalous cyclonic circulation to the northwest through a Gill-like atmospheric response (Gill, 1980), which is conducive to the maintenance of the western Pacific subtropical high over the Yangtze River valley, resulting in the positive SAT anomalies over the region, and vice versa.