中蒙地区沙尘暴研究的若干进展

Some advances in dust storm research over China-Mongolia areas

本文首先回顾了近20多年来我国沙尘暴研究的3个主要阶段,然后从沙尘观测、沙尘暴气候学、沙尘暴爆发和沙尘传输的环流型、沙尘暴活动的年代际变化和原因、以及待深入研究的问题等5方面简要评述了它的研究进展和问题.指出中蒙沙尘主要来源于中国西北及蒙古国南部和西北部地区;随沙尘天气强度逐渐加强(即从背景大气到浮尘、扬沙、沙尘暴、强及特强沙尘暴),它们的地面沙尘浓度约按3倍的比率依次递增;揭示了我国北方及蒙古国南部的七大沙尘暴多发区,沙尘暴主要出现在春季午后至傍晚间,丰富的沙源,强风和不稳定的大气层结是形成沙尘暴的3个主要因子;中蒙地区沙尘暴爆发的环流主要有低压冷锋型和低压、冷锋加中尺度系统的强对流型两类,前者占绝大多数,后者是极少数,但为沙尘暴爆发短期预报的难点,沙尘的传输主要决定于低空环流型;近50年来中蒙地区的沙尘暴活动呈波动变化,而且中蒙中、东及西区三区系的变化不完全相同.它们与北方风沙区生态环境恶化,特别是蒙古及日本海附近气旋频数的年代际变化有关;防御沙尘暴重点要抓上述七大多发区生态环境的治理及沙尘暴预警系统的建立,治理措施要因地制宜;要加强沙尘暴爆发和沙尘输送的数值预报和模拟研究.

To give a up-to-data review of the present status of dust storm （hereafter DS） research over ChinaMongolia Areas （CMA）, first, the three stages of China DS research in the last 20 years are reviewed, Then the main advances in dust aerosol observations, DS climatology, circulation patterns of DS outbreak and dust transport, DS activity changes in the past five decades and their causes, as well as some problems remain to be solved are presented. It is pointed out that the DS in CMA originates mainly from both the Northwest China and South- and Northwest-Mongolia. With the intensifying of the dust weathers, the dust thickness, total suspended particulates （TSP） of dust at the surface will increase in geometric series at the rate of 3 times. There exist seven high DS frequence regions in CMA, which are the Gansu Corridor, Tarim Basin, Mid-and West-Inner Mongolia, Hunshandake sand region in China and Dalanzadgad and Zamin Uud in Mongolia. Most of DS events occur between 13：00 to 20：00 Beijing time in spring. There are briefly two kinds of DS outbreak circulation patterns in CMA, i.e., the low pressure plus cold front and the low, cold front plus meso-scale system. The former makes up the most of them; the latter a few percent only, but the latter is one of the most important disaster weathers to forecast. The dust transporting toward downwind mainly depends on the circulation on lowerlevels. In the past five decades the DS activities in CMA change in a wavy way, first gradually increase from the 1950s to the 1970s, get its peak frequency in the 1970s; then gradually decrease from the 1980s to the 1990s; again then increase suddenly in 2000 and 2001 and still decrease suddenly from 2003 to 2005. The main factors which cause the DS interdecadal changes may be related closely to the interdecadal changes of East Asia atmospheric circulation, not the desertification condition. Finally three aspects which need to be further studied are suggested.