The Material Character of Sand Dust and Analysis on the Cause of Formation of the Sand-Dust Storm in Northeast District in Spring of 2002
东北地区2002年春季沙尘暴的物质特征和成因分析

The paper analyzed the particle distribution,pollen combination of sand dust storm in northeast district in spring, 2002.It was found that there is abundant pollen,based on pollen combination sand source at new angle can be analyzed,and the distribution laws of the bowling sand and sand dust storm in season, in yearly, in geological periods and mankind historic periods can be explained. The blowing sand and sand dust storm often appeared in geological period and mankind historic period in northeast district, and mainly appeared in winter and in spring and they dropped fluctuationally in fifty years. The frequency of the sand dust storm increased since 2000. The frequency of blowing sand and sand dust storm was controlled by the strength of the monsoon wind in winter. Which the Enino and anti Enino alternately occurs was influenced by the periodic change of the strength of monsoon wind in winter in Eastern Asia. The cold and dry climate combination in winter and spring was favorable of the occurrence of sand dust weather. The frequency of the sand dust weather will not obviously increase in several years.