辽宁地区大气可降水量与降水关系的研究  

Relationship Between Atmospheric Precipitable Water Vapor and Precipitaton in Liaoning Province

作　　者：秦鑫[1] 赵姝慧[1] 马嘉理 孙丽[1] 刘旸[1] 房彬[1] QIN Xin;ZHAO Shuhui;MA Jiali;SUN Li;LIU Yang;FANG Bin(Liaoning Weather Modification Office,Shenyang 110166)

机构地区：[1]辽宁省人工影响天气办公室

出　　处：《气象》2020年第1期80-88,共9页Meteorological Monthly

基　　金：国家自然科学基金项目(41705127);辽宁省气象局科研项目(201608)共同资助

摘　　要：当大气可降水量(precipitable water vapor,PWV)达到某一阈值时将出现降水,则该值称为PWV降水阈值(threshold of PWV,PWVt),由此认为PWVt可以作为PWV与降水关系研究的纽带。为了能够较为准确地计算出PWVt,引入整层大气饱和可降水量(precipitable water vapor saturation,PWVsat)概念,并推导出多元大气条件下PWVsat计算公式,根据公式可知PWVsat是地面温度(ts)的函数,其表示整层大气在饱和状态下容纳的最大水汽量。大气必须达到一定层次的饱和才能成云致雨,因此推断ts也可能影响着PWVt。为了验证该推断的准确性,利用2015年5月至2016年10月辽宁地区36个观测站的PWV与ts进行研究,将筛选出1122个降水样本的PWVt与ts进行拟合,发现PWVt拟合公式与PWVsat推导公式较为一致,说明PWVt和PWVsat两者密切相关,同时给出36个站的拟合参数,从而建立PWV与降水的对应关系。统计检验表明,该方法在降水预报中的准确率、漏报率和空报率分别为93.69%、2.32%和3.99%,说明PWVt在降水预报方面具有一定的应用价值。最后在一次降水个例中应用,结果显示PWVt可以较好地预报降水,并发现PWV与PWVt的差值与降水量具有一定的对应关系。Precipitation is likely to take place as precipitable water vapor(PWV)of the atmosphere reaches a certain value.Thus,the threshold of PWV(PWVt),which can be regarded as the research bridge between PWV and precipitation.In the aim of calculating PWVt precisely,this paper has brought in"precipitable water vapor saturation(PWVsat)"of the atmosphere and deduced the computing formula of PWVsatunder various atmosphere conditions.From the formula,it is shown that PWVsat is a function of surface temperature(ts),which indicates the maximum water vapor that a bottom-up saturated atmosphere is capable to hold.The atmosphere needs to be wet enough to form clouds and rains.Therefore,it is inferred that ts is a factor in PWVt.To prove that,PWVt and ts of 36 gauge stations ranging from May 2015 to October 2016 are studied and 1122 precipitation cases are selected and fitted.The results show that the fitting formula of PWVt and computing formula of PWVsat are highly alike,proving the 2 variables are closely correlated.Meanwhile,fitting parameters of each of 36 stations are given for relating PWV to precipitation.This method has gone through statistical examination to find that its accuracy rate,missing rate and vacancy rate to be 93.69%,2.32%and 3.99%respectively in precipitation prediction,which denotes a sound application value in predicting rainfall.Finally,the method is applied in a rainfall case to show that PWVt can predict precipitation well,and the difference between PWV and PWVt is correlated to precipitation amount.

关 键 词：积分水汽总量 整层大气饱和水汽含量 降水预报 阈值 拟合 

分 类 号：P426[天文地球—大气科学及气象学] P435