基于多相态KE-I关系的降水动能计算方法  

Calculation of Precipitation Kinetic Energy Based on Multi-Phase KE-I Relationship

作　　者：孙晨玥 戴强[1] 纪端阳 顾于 刘超楠 李雁鹏[2] SUN Chenyue;DAI Qiang;JI Duanyang;GU Yu;LIU Chaonan;LI Yanpeng(School of Geography,Nanjing Normal University,Nanjing 210023,China;Public Meteorological Service Center,China Meteorological Administration,Beijing 100081,China)

机构地区：[1]南京师范大学地理科学学院,南京210023 [2]中国气象局公共气象服务中心,北京100081

出　　处：《山地学报》2023年第5期771-784,共14页Mountain Research

基　　金：国家自然科学基金(42371409,41871299)。

摘　　要：降水动能描述了水凝物到达地表的动能大小,是计算土壤颗粒分离和土壤侵蚀等地表物理化学过程的重要参数之一。针对目前降水动能计算多考虑降雨特征,忽略其他相态降水的问题,本研究基于2018年全国25个雨滴谱仪站点的降水观测数据,结合速度(V)-直径(D)关系对水凝物进行相态划分,拟合了不同相态降水的降水动能-降水强度(KE_(V)-I)经验公式,总结出适用于雨、雪、雹的动能计算关系模型,并对各相态降水动能进行偏差分析和校正。结果表明:(1)降雨动能计算适用KE_(V)-I指数型关系公式,降雪和降雹动能计算适用幂函数型关系公式;(2)降水动能偏差与总降水中非液态占比呈正相关,仅以降雨KE_(V)-I经验公式估算所有相态降水的动能会显著高估降雪动能和低估降雹动能,对降水整体估算偏差在-0.05到0.31之间;(3)通过建立各相态的KE_(V)-I计算模型,降水整体估算误差得到有效降低,降雪偏差从7.08降至-0.05,降雹偏差从-0.29降至0.03。本文所提出的方法能够有效提高降水动能估算的准确度,为区域土壤水力侵蚀计算提供更好的支撑。Precipitation kinetic energy,which describes the magnitude of the kinetic energy of hydrometeor reaching earth surface,is one of the important parameters for calculating surface physicochemical processes such as soil particle separation and soil erosion.Rainfall characteristics were often considered in the calculation of precipitation kinetic energy,but precipitation in other phases was ignored.In this study,it started from a primitive phase classification of hydro-condensate,followed by an analysis of the correlation between kinetic energy per unit volume of precipitation(KE_(V))and precipitation intensity(I);based on meteorological observations at 25 raindrop spectrometer stations nationwide in 2018,it further classified hydrometeor into phases by examining velocity(V)-diameter(D)correlation of hydrometeor;after fitting empirical equations of KE_(V)-I for precipitation in different phases,it introduced a series of precipitation kinetic energy estimation models applicable to rainfall,snowfall,and hailfall.The statistical significance of KE_(V)-I fitting was carefully justified by field observations in terms of Relative Error(RE),Mean Absolute Error(MAE),and Root Mean Square Error(RMSE).It found that(1)the KE_(V)-I exponential type formula was applied to the calculation of rainfall kinetic energy,and the KE_(V)-I power function type formula was applied to the calculation of snowfall and hailfall kinetic energy.(2)The deviation of calculating precipitation kinetic energy was positively correlated with non-liquid fraction of total precipitation.Supposing that the kinetic energy of all phases of precipitation were estimated entirely by the KE_(V)-I fitting of rainfall,it would significantly overestimated snowfall kinetic energy but underestimated the hailfall kinetic energy,with a deviation of-0.05 to 0.31 in extent from an overall precipitation estimate.(3)By establishing separate KE_(V)-I calculation model for respective phase of precipitation,the overall estimation error of precipitation was effectively reduced.T

关 键 词：降水动能 雨滴谱 KE-I 降水强度 相态分类 偏差计算 

分 类 号：P412.13[天文地球—大气科学及气象学]