The Characteristics of Sand and Dust Weather Events in China in 2005
2005年我国沙尘天气的若干特征分析

In 2005,totally 11 sand and dust weather processes including 4 sand and dust storm processes and 1 severe sand and dust storm process occurred in China,when the frequency of sand and dust weather is obviously few,the intensity is obviously weak,and the area affected is obviously small.The sand and dust weather processes in the spring(from March to May) are obviously less than the mean values in the recent 6 years,the sand and dust storm and severe sand and dust storm processes are far less than those in 2000,2001,and 2002,respectively.The total number of sand and dust weather days,as well as sand and dust storm days, is four to seven tenths less than normal in this spring from 2000 to 2005 which is the smallest value in the recent 6 years;The results show that there are more precipitation,more surface snow cover and larger humidity of soil layer in northern China in winter in 2004/2005,which are the main reasons for the obviously less sand and dust weather with weaker intensity in 2005.In addition,at the end of last winter and the beginning of this spring,the temperature in north China is relatively low and the soil defrosts late,which delay the occurrence of sand and dust weather and cause the few sand and dust weather in early spring and dust high-frequency period is late.