Effects Of Cloud Top Above The Tropopause On The Water Vapor Structure In The Upper Troposphere And Lower Stratosphere

The distributions of atmosphere water vapor in the upper troposphere and lower stratosphere (UTLS) play an important role in the radiation energy balance of global earth-atmosphere system, with its weather disturbances great. In consideration of the characteristics, based on the satellite data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) and Microwave Limb Sounder (MLS), combined with ECMWF interim reanalysis dataset, the distributions of cloud top above the tropopause (CTAT) are studied. Moreover, the effects of CTAT on the water vapor structure in the UTLS are analyzed, the relationship between CTAT and two kinds of typical cyclone activities over East Asia in summer explored. Several conclusions are listed as followings:(1) The total vertical cumulative fractions of CTAT near the ITCZ tend to be the maximum, in the subtropics with minimum and in the mid-latitude temperate fronts with the second largest. In the tropics, CTAT are mainly distributed in three areas:the Asian monsoon region, Central America and West Africa. The maximum frequency and extent of CTAT is in the Asian monsoon region, exceeding over 25%. What’s more, for the area cumulative CTAT fractions of the region in the northern hemisphere, Asian monsoon region is 49.0%, Central America about 13.5%, West Africa reaching 12.4%. From the vertical structure, there are differences among different height of the maximum fraction of CTAT near ITCZ. The height can exceed 17km in the Asian summer monsoon region, higher about 1km than Central America and West Africa,3km in subtropics. The distribution patterns are closely related to the atmospheric circulation near the Tibetan Plateau. It is the south and north sides of South Asia High corresponding with the easterly and westerly jet, and water vapor transport of meridional monsoon circulation that make its south side the maximum region of CTAT in the world summertime.(2) The composited water vapor and temperature structure of CTAT in East Asia indicate that positive anomalies of water vapor are more significant in the area south of 35°N. In the subtropical regions, temperature is bounded by 150hPa, positive anomalies in lower levers, however, negative anomalies in higher levers, which are in consistent with the typhoon structure of "down warm and up cold". What’s more, in the mid-latitudes of East Asia, temperature is bounded by 150hPa as well, negative anomalies in lower levers, while positive anomalies in higher levers, accordant with the middle-latitude frontal cyclone structure of "down cold and up warm".(3) Through the composited analysis of typhoon in East Asia, in the neighborhood of typhoon center, water vapor shows great positive anomalies, temperature revealing "down warm and up cold", which is corresponding to CTAT composited water vapor and temperature structure in this area. It indicates that typhoon is the predominant impact factor of CTAT in this region. Through the composited analysis of zone cyclone in Northeast Asian region, in the neighborhood of zone cyclone center, water vapor shows the asymmetric structure of front, temperature revealing "down cold and up warm", totally different from the tropical cyclone. Meanwhile, it corresponds to CTAT composited structure in this area, which indicates that zone cyclone is the predominant impact factor of CTAT in this region. Thus, two kinds of typical weather systems over East Asia in summer are closely linked with the corresponding positions of CTAT and the water vapor and temperature structure in the UTLS.