新疆及周边中亚地区中亚低涡背景下云中液态水分布研究

Distribution of total cloud liquid water in Xinjiang and its surrounding Central Asia under the background of low vortex in Central Asia

利用2003—2014年5~9月中亚低涡发生时的AIRS Version 6 Level 2卫星资料,分析中亚低涡活动规律以及云中液态水空间分布。结果表明:(1)北涡型中亚低涡共发生97次,南涡型共88次。中亚低涡中心更易向南移动。(2)整体来看,云中液态水呈现山区多盆地少的趋势,在帕米尔高原、天山和昆仑山脉的山区以及咸海附近均大于100×10-6 kg·m-2。在准噶尔盆地、哈密盆地和塔里木盆地东部地区小于1×10-6 kg·m-2。(3)中亚低涡发生路径越偏南,云中液态水柱越低。关于云中液态水柱,北涡路径较南涡路径更多。研究结果将为进一步认识中亚低涡强降水天气系统提供参考。

Xinjiang,China and surrounding Central Asia region belong to the same typical arid and semi-arid climate.Water resources are scarce and surface vegetation is scarce.Once a sudden heavy precipitation occurs,it is easy to threaten the water conservancy system.The central Asian vortex is the main system that causes heavy precipitation in Xinjiang and the surrounding Central Asian region.The precipitation process includes the transformation of water vapor and ice particles in the atmosphere.The liquid water in clouds can interact with these water molecules to maintain the balance of water budget in the atmosphere.In order to study the liquid water in clouds under the background of the central Asian vortexes in Xinjiang,observation data are needed.Based on the AIRS Version 6 Level 2 satellite data from May to September in 2003 and 2014,the activity of the central Asian Vortex and the spatial distribution of liquid water in clouds are analyzed.In the process of satellite data acquisition and processing,the data of all pixels in 0.25×0.25 grid points are averaged first,then interpolated to each grid point,and the monthly average spatial distribution map is drawn according to the grid points.The results show as follows:(1) The Northern Vortex Type of the central Asian vortexes occurred 97 times.The Southern Vortex Type of the central Asian vortexes occurred 88 times.The activity center of the central Asian vortexes is more likely to move southward.The monthly frequency of the North Vortex in summer and half a year shows a single peak type.The monthly frequency of the North Vortex in summer and during half a year shows a "W" shape.(2) Overall,the liquid water in clouds tends to be more in the mountainous areas and less in the basin areas.It is more than 100×10-6 kg·m-2 in the mountainous areas along the Tianshan and Kunlun Mountains and in the vicinity of the Aral Sea in the Pamir Plateau.In Junggar Basin,Hami Basin and the eastern Tarim Basin,it is less than 1×10-6 kg·m-2.This is because the Himalayas and Kunlun Mountains prevent water vapor from entering Xinjiang from the Indian Ocean.(3) The more southward the occurrence path of the central Asian vortexes was,the lower the liquid water content in the cloud was.The cloud liquid water content in the North vortex path is higher than that in the South vortex path.The above research could provide a new early warning index for heavy rainfall in this area.