2006年春季沙尘天气异常的气候背景分析及趋势预测检验

作者概述了2006年春季我国北方地区沙尘天气异常的观测特征.与2000～2005年同期相比,2006年春季,我国北方地区沙尘天气过程相对频繁,强度偏强.首先,利用NCEP再分析资料及台站观测资料,对可能影响2006年春季我国沙尘天气异常的气候背景进行了分析,结果表明:2006年春季北方地区冷空气势力较常年强,冷空气活动较频繁,这是造成2006年春季我国沙尘天气多于前几年的动力原因.此外,春季我国西北及内蒙古的沙源地区降水偏少,干旱少雨,加之春季气温偏高,在一定程度上也有利于沙尘天气的形成.利用IAP 年度数值气候预测系统对2006、2007年春季我国沙尘天气趋势的气候背景进行了预测,检验了系统对2006年沙尘趋势的预测能力,并对2007年春季沙尘天气趋势进行了展望.结果表明:预测系统较好地预测出2006年我国北方地区春季降水偏少、土壤偏干的状况,但对风场的预测与实况有一定的差距,由预测的气候距平结果推断2006年春季我国北方沙尘次数正常略偏少,与实况相反;对2007年春季的预测结果表明,2007年春季我国北方,特别是西北及内蒙古沙源地区土壤湿度偏湿,冷空气活动势力偏弱,不利于沙尘天气的形成,由此预测2007年春季我国北方沙尘趋势与常年相比略偏弱.

Climatic Background for the Anomalous Spring Dust Storms over Northern China during 2006 and the Verification for Real-time Climate Prediction

Base characteristics of the anomalous spring dust storm in 2006 have been analyzed in this paper,and it is found that the spring dust storm in 2006 happened frequently and is stronger than the usual.By using NCEP reanalysis data and observational data in station,the climatic background which may be responsible for the spring strong dust storm activities in 2006 has been investigated.The preliminary results show that,in 2006 spring,the activitive cold air was favorable for the occurrence of the spring stronger dust storm.Meanwhile,the precipitation in northern China was less than the normal during the spring of 2006,the surface condition was drier than the normal,and the air temperature over source regions of dust storm was higher than the average,all these will favorable for the formation of dust storm during springtime in 2006.By using the real-time prediction results produced by Institute of Atmospheric Physics(IAP),Chinese Academy of Sciences annual climate prediction system,the prediction trend of spring dust storm events in 2006 has been verified well,and the trend in 2007 has been discussed.Results show: though the surface wind anomaly in northwestern China has not been very successfully reproduced by IAP Dynamical Climate Prediction System in 2006 spring,the rainfall anomalies and soil moisture anomalies in northern China has been well predicted,verification of real-time prediction expressed that the prediction for trend of the dust storm in 2006 spring is opposite to the observation.In 2007 spring,the predicted soil condition in the northern China is wet,and cold air is weaker than the normal.So,it could be expected that,in 2007 spring,there will not be so many opportunities for the occurrence of strong dust storm.