热带地区积云对流的长期变化特征

使用１９７９年１月至１９８４年１２月向外长波辐射（ＯＬＲ）资料，对热带地区积云对流的长期变化特征进行了研究。结果表明：热带地区积云对流活动存在显著的季节变化，冬季积云对流区主要是东西向，位于南印度洋和西太平洋的近赤道地区；夏季则北移至北印度洋和菲律宾附近的西太平洋地区。低纬地区积云对流活动存在明显的季节性位移，北印度洋地区的积云对流活动主要集中在５—１０月，７—８月位置最北；北半球热带西太平洋地区的积云对流活动则主要集中在６—１１月，８—９月位置最北。标准差分析表明，冬季北半球热带西太平洋、赤道中太平洋及热带印度洋东部地区积云对流的年际变化最明显。经验正交函数（ＥＯＦ）分析的主要空间型反映了赤道中太平洋、热带西太平洋、阿拉伯海和副热带西太平洋地区的积云对流活动存在一定的关系。结合遥相关计算还表明秋云对流存在４种遥相关型，即２种东西向偶极型涛动型、西太平洋型和北印度洋型。

LONG-TERM VARIATION FEATURES FOR CUMULUS CONVECTION OVER THE TROPICAL REGION

Using OLR data of 1979 to 1984, the long-term variation features for cumulus convection over the tropical region are studied. The eresults show that cumulus convection is of obvious seasonal variation features, i. e. the cumulus convection regions are mainly in the east-west direction located in the southern Indian Ocean and equatorial western Pacific during NH winter, and in the northern indian Ocean and the western Pacific near Philippine Islands during NH summer. The cumulus convection over low latitude region is of obvious seasonal motion. The cumulus convection over the northern Indian Ocean often occurs during the period between May to October, and its area of occurence is northest during July; the cumulus convection over NH tropical western Pacific often occurs during the period between June to November, and its area of occurence is northest during August. The analysis about standard deviations reveals that during NH winter the regions of great interannual variation for cumulus convection are located in NH tropical western Pacific, equatorial middle Pacific and the eastern region of the tropical Indian Ocean. The EOF analysis indicates the relationship of the cumulus convection between equatorial middle Pacific, tropical western Pacific, the Arabian Sea and subtropical western Pacific. By combining the correlation computations of teleconnection, we find four teleconnection patterns for cumulus convection variations in the analyzed area,i. e.,the east-west patterns, a western Pacific (WP) pattern, and a northern Indian Ocean (NI) pattern.