地面冻结状况与春季沙尘暴发生的关系

利用30年地面气象观测数据,以内蒙古锡林郭勒盟中西部地区为研究区,以土壤表面冻结终日与沙尘暴发生日数为指标,分析了地面冻结终日与春季沙尘暴发生日数之间的关系。研究结果表明:在研究区内,土壤表面冻结终日与春季沙尘暴发生日数之间呈现负的相关关系,说明土壤表面冻结终日对春季沙尘暴的发生有一定的影响,也表明了其对沙尘暴的发生有进行指示和监测的潜力;但部分地区的相关关系不显著,说明土壤表面冻结状况只是影响春季沙尘天气的一个因子,它对沙尘天气所产生的影响是有限的。

Relationship between soil freezing and thawing condition and sandstorm occurrence

Soil surface freezing affects the occurrence and development of sandstorm mainly by changing the sand and dust sources on the ground.When temporary frozen soil early thaws,its moisture will reduce and its dryness will increase,which makes the particles on soil surface become loose,and dust material susceptible to the air with the wind.The small particles in the loose soil surface will be whipped up into the air as dust by strong winds.Therefore,the soil surface freezing and thawing conditions are linked with the occurrence of sandstorm in spring.Especially in late winter and early spring,before grass turning green,with the frequent cold air activities,the situation of the ground is particularly important for sandstorm development.In this study,an analysis is performed on the relationship between sandstorm days and end dates of soil freezing in spring in western and middle of Xilingol in Inner Mongolia,taking sandstorm days and soil freezing end dates as indexes and using meteorological observation data of earth surface from 1971 to 2000.The result shows that in this area there is a negative interrelation between sandstorm days in spring and the end dates of soil surface freezing,which varies in difference areas.When the soil surface thaws earlier,the spring dust storm occurrence shows an upward trend.When the end date of soil surface freezing is deferred,the spring dust storm days show a decreasing trend,which indicates that the end date of soil surface freezing affects the occurrence of sandstorms to a certain extent in spring.There is a negative interrelation between sandstorm days in spring and the end dates of soil surface freezing.But the relationship was not significant in some areas. So soil surface freezing condition is only one of factors affecting spring sandstorms and its impact is limited.This study has not yet developed the quantitative relationship between the end dates of soil surface freezing and sand-dust storm days in spring,but it shows that to study sand-dust storm not only needs to analyze the dynamics factor of weather,but also need to analyze land surface factors.