哈尔滨沙尘天气的源地分析

本文对哈尔滨2002年3月20日的沙尘暴沉积物进行了粒度分析研究。结果表明:沉积物4—8Ф的粉砂占71.18%,>4Ф的砂粒组分占21.7%,<8Ф的粘土组分仅占7.13%;粒度分布呈现三峰态特征,4.85—5.10Ф粒级组成第一主峰,1—1.25Ф粒级为第二主峰,10.25—10.5Ф粒级形成第三主峰;平均粒径Mz为5.14Ф。哈尔滨沙尘暴沉积物是迄今为止有见报道中最粗的,是不同来源沙尘远距离和近距离搬运的混合体。本文认为哈尔滨市沙尘暴的远距离沙源为内蒙古镜内沙地、科尔沁沙地、近距离沙源为松嫩平原和哈尔滨周边地区。

Research on the Sand-dust Sources of Harbin City

This research deals with the grain size distribution of dust felled deposits,took place in Harbin on Mar.20,2002.The results indicated that sand dust sedimentation gave priority to silt(4—8Φ),occupied 71.18%,sand composition(>4Φ) 21.7% and clay composition(<8Φ)only 7.13%.The sedimentation granularity distribution was charactered by there-peak states,thick silt of 4.85—5.10Φgrain grade composed first main peak,medium sand of 1—1.25Φgrain grade composed second main peak,and clay composition of 10.25—10.5Φgrain grade composed third main peak.The average grain diameters of sedimentation(Mz) was 5.14Φ.The granularity of sand dust sedimentation was the coarsest in the reports,so far.At the same time,sand-dust sedimentation was admixture,derived from different sources both far distance and nearby,and coarse particle was near-sources material that was transmitted by low altitude airflow.The sand-storm sedimentation in Harbin on Mar.20,2002was the mixture of coarse sand and fine dust.It was pointed out that the long range source of dust-storm was Gerqin desert,and the short range ones were Songnen plain and the surroundings of Hrbin.