Study For The Variation Of Water Vapor During The Heavy Snow In Urumqi Based On The Data Of The Microwave Radiation

As an important meteorological parameter, atmosphere precipitable water is themost active ingredient in the hydrologic cycle. Regional atmosphere precipitablewater is one of important issues in the meteorology and climatology. The heavystorms made a great property and economic losses for farmers and herdsmen. In orderto reduce the damage of the heavy storms, and improve the accuracy for weatherforecast, this paper used microwave remote sensing to detect atmospheric water vapordensity and liquid water content to find out the changes threshold in the process ofsnow. Through this, to provide technical support for the weather forecast andshort-term nowcasting.The atmospheric water vapor is mainly concentrated in the height of the850hPaand700hPa in winter. In850hPa,water vapor density values are basically in the rangeof2.900~3.800g·m-3,in700hPa,water vapor values are generally between the rangeof1.10~1.90g· m-3. And in the3~6hours before the snowfall occurred, in heightbetween850hPa and700hPa,atmospheric water vapor increase of magnitude, that isbefore the snowfall twice, and this value is continuous growth. After snow, this valuewill be fall to normal levels.The liquid water content is low in Urumqi’s winter. In the height below850hPa,the liquid content value is no more than0.007mm,and in the height below700hPa,this value is lower than0.003mm. As the altitude increases, atmosphericliquid water content is decreased. But in the process of snow, the atmosphere liquidwater content is gradually increased, the maximum value appeared in the moment ofthe biggest snowfall, and mainly concentrated in the height below2200m.Compared with the other seasons, the atmospheric precipitable water in winter isthe lowest, the precipitable water below in0.6cm. From the experimental analysisfound that the precipitable vapor increased continuously, and after more than twoorders of magnitude, the snow will be fallen in next4to5hours. But if theprecipitable water value more than mean the scale of three, the snow will occur withinthe next1hour.