南疆和田地区“3.12”强沙尘暴天气过程诊断分析

Analysis of Strong Sandstorm in Hotan Region of South Xinjiang Province on March 12

摘要: 为了进一步研究南疆沙尘暴天气过程的主要成因，探讨沙尘暴发生的有利环流形势和具有指示意义的主要物理量场，利用常规气象观测资料，以及1˚ × 1˚ NCEP/NCAR格点分析资料，从环流形势，中低层影响系统及客观物理量场对2010年3月12日发生在新疆和田地区的强沙尘暴天气过程进行了天气学分析和诊断，得出如下结论：1) 沙尘发生前，3月上旬极涡较往年偏强，并偏向东半球，这有利于极涡中心分裂的冷空气不断南下侵袭我国，为沙尘暴天气的爆发提供了有利的环流背景条件，3月12日北半球环流形势发生明显调整，新地岛附近的强冷空气爆发向南侵袭，从而造成南疆和田地区本次强沙尘暴天气。巴尔喀什湖附近冷涡及强锋区是这次新疆和田区域强沙尘暴天气的主要天气系统。2) 沙尘来临前，和田地区为热低压控制，之后随着地面冷高压和冷锋不断东移，和田地区形成很强的气压梯度，沙尘暴过境时，造成气压猛升，气温骤降，相对湿度增加，风速突增等基本气象要素变化特征。3) 物理量场分析表明：本次沙尘暴发生在高空急流右侧，高空急流的存在使得高空动量下传，引起近地面大风，当大风经过沙尘源区时，形成沙尘暴天气。沙尘发生前，和田上空处于能量高值区，低层大气处于对流不稳定状态，容易形成强烈的上升运动。

Abstract: In order to further study the main causes of sand dust storm process in southern Xinjiang, to explore the favorable circulation situation of sandstorm occurrence and main physical quantity is the indication of the field, the use of unconventional meteorological observation data, forecast products of MICAPS and 1˚ × 1˚ NCEP/NCAR reanalysis data, the synoptic situation, the impact of low-level and objective physical system the amount of field occurred on March 12, 2010 in Xinjiang and Hotan Sandstorm Process of analysis and diagnosis of the weather, draw the following conclusions: 1) The dust before early March than in previous years, the strong polar vortex, and towards the eastern hemisphere, which is conducive to the center of the polar vortex splitting of cold air from north to South China invasion that provided the favorable circulation background for the sandstorm weather outbreak of March 12th in the Northern Hemisphere Circulation situation was adjusted, the strong cold air near the island of South new outbreak of invasion resulting in Hotan region, the strong sandstorm weather. Balkhash lake near the cold vortex and the strong frontal zone is the main weather system of the Xinjiang Hotan Regional Severe Sandstorm weather. 2) Before the arrival of the dust, Hotan Prefecture for low-pressure heat control, with surface cold high pressure and the cold front moving eastward from Hotan region, and forming a strong pressure gradient, the sandstorm, pressure caused by the sudden rise, the sudden drop in temperature, with the increase of relative humidity, wind speed increased basic gas as the feature changes. 3) The physical quantity field analysis shows that the dust storms occur in the right side of the upper level jet and upper level jet existence makes the air momentum transfer, caused by near surface wind. When the wind goes through the headstream zone, there comes the sandstorm weather. Before the dust event, the high energy region is in the high energy region, and the low atmosphere is in the unstable state of the convection, and the strong ascending motion is easy to form.