东北地区2002年春季沙尘暴的物质特征和成因分析

沙尘暴是东北地区冬春季一种常见的灾害性天气,研究东北地区沙尘颗粒的特征,来源和成因是防止沙尘暴的关键.通过对东北地区2002年春季沙尘暴物质的粒度分析和孢粉分析,发现沙尘暴物质中孢粉丰富,主要以草本中的蒿属和藜科为主.沙尘颗粒的中值粒径为10～20μm. 通过粒度分布曲线和孢粉组合可以从新的角度分析沙尘来源.通过对扬沙和沙尘暴季节分布规律,多年分布规律和地质历史时期及人类历史时期的出现规律的研究,发现东北地区扬沙沙尘暴以冬春型为主,50年中冬春季发生沙尘天气的次数占总次数的75%.在地质历史时期和人类历史时期扬沙和沙尘暴就频繁出现,50年来,扬沙和沙尘暴在波动中减少,2000年开始在东北地区扬沙和沙尘暴出现频率增强.东北地区扬沙和沙尘暴出现频次、强度和分布的南界受冬季风强度控制,冷干组合是沙尘暴高发的有利条件.

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

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.