摘要
分析了春夏转换季节中亚洲季风区北半球副热带高压断裂的气候学特征及其可能机制.分析表明,北半球副高断裂最先发生在孟加拉湾-中南半岛一带.孟加拉湾和中南半岛地区经圈环流的季节转换在高低层存在差异.在3～5月的经圈环流演变中,孟加拉湾地区经圈环流表现为对流层低层首先发生改变,呈高、低层正、反Hadley环流配置,大气加热以感热为主,因而高度场表现出的副高在孟加拉湾首先断裂只是对流层低层的表现.中南半岛则表现为从低到高的整层上升运动增强,经圈环流的减弱、消失是地表感热和潜热共同作用的结果,因而整个对流层副高的断裂应在中南半岛地区.中纬度亚洲大陆积雪季节溶化以高原为中心表现出东快西慢特征,导致105 (E以东的东亚中纬度感热首先增加,地表感热加热大气的结果有利于大气经圈环流下沉气流减弱,从而加剧了中南半岛地区经圈环流减弱进程,为北半球副高在孟加拉湾-中南半岛地区断裂提供了大尺度气候变化背景.
Characteristics of the Northern Hemisphere sub-tropical high seasonal splitting from spring to summer and its possible mechanisms have been analyzed on the basis of climatological data sets. Results suggest that the splitting of the sub-tropical high occurs over the Bay of Bengal to the Indo-China peninsula. However, since March to May, remarkable contrast exists in the meridional cell at the lower and upper level over these sectors, where the land surface sensitive/latent heating fluxes both play an important role and cause the local Hadley cell over the Indo-China peninsula to exhibit an enhanced vertical upwelling in behavior, in contrast to the dominant land surface sensitive heating flux which causes the vertical, local reversed Hadley cell over the Bay of Bengal. Thus, the vertical splitting of sub-tropical high in unity should be over the Indo-China peninsula, rather than the Bay of Bengal at lower levels. In addition, the analysis also suggests that the faster seasonal land snow melting in the east of Indo-China peninsula can enhance the quickly increasing land surface sensitive heating of atmosphere and weaken the local Hadley cell in these sectors, which supplies a favorable climate background for the splitting of Northern Hemisphere sub-tropical high.
出处
《热带气象学报》
CSCD
北大核心
2004年第3期237-248,共12页
Journal of Tropical Meteorology
基金
"863"项目(2002AA135360)
国家自然基金重点项目(40135020)
国家自然科学基金(40375014)
教育部优秀青年教师资助计划
中科院大气物理研究所LASG开放课题
关键词
季节转换
副高断裂
机制分析
seasonal transition
sub-tropical high splitting
mechanism analysis
