4—5月南亚高压在中南半岛上空建立的年际变化特征及其与亚洲南部夏季风的关系

利用1979--2008年NCEP／NCAR逐日再分析资料和向外长波辐射资料讨论了4-5月南亚高压在中南半岛上空建立的年际变化特征及其与亚洲南部夏季风的关系。发现南亚高压建立偏早年其建立过程时间长，中南半岛高空反气旋环流强，建立开始前位于菲律宾群岛以东洋面上空的反气旋环流中心位置较为偏西；偏晚年南亚高压建立过程时间短，中南半岛高空反气旋环流弱，建立开始前西太平洋上空无闭合的反气旋性环流中心。南亚高压建立的早晚与中南半岛地区对流建立发展关系密切，当中南半岛地区对流建立发展较早时，南亚高压建立较早；反之，对流建立发展偏晚时，南亚高压建立偏晚。南亚高压建立早晚年，亚洲南部夏季风的爆发存在明显差异。南亚高压建立偏早年，孟加拉湾东部一中南半岛夏季风和南海夏季风爆发早；建立偏晚年，孟加拉湾东部一中南半岛夏季风和南海夏季风爆发晚，因此南亚高压在中南半岛上空建立的早晚对后期亚洲南部夏季风的爆发具有较好的指示意义。

Interannual variability of the South-Asian high establishment over the Indo-China Peninsula from April to May and its relation to Southern Asian summer monsoon

Interannual variability of the South-Asian high （SAH） establishment over the Indo-China Peninsula（ICP） from April to May and its relation to southern Asian summer monsoon are investigated by using NCEP/NCAR daily reanalysis and out-going longwave radiation （OLR） data from 1979 to 2008. It is found that the duration of the SAH establishment is relatively long （short） in the early （ delayed）-establishment years. The upper tropospheric anti-cyclone over the ICP is stronger（weaker） in the early （delayed） years. Before the SAH establishment, the center of the anti-cyclone to the east of the Philippines is to the west of its normal location in the early years. But in the delayed years, there is not a closed anti-cyclone over the western Pacific before the SAH establishment. The time of the SAH establishment is closely associated with the convective development over the ICP. The earlier （later） convective flourish is corresponding to the earlier（later） SAH establishment. The onset of southern Asian summer monsoon in early-establishment years is significantly different from the delayed years. The earlier（later） SAH establishment is followed by the earlier（later） onset of the Bay of Bengal（BOB）-ICP summer monsoon and the South China Sea summer monsoon. Accordingly, the time of the SAH establishment over the ICP plays an indicative role in the subsequent onset of the southern Asian summer monsoon.