鄱阳湖对降水强度减弱的物理过程的数值模拟研究  

Numerical Simulation of Physical Process of Precipitation Intensity Weakening in Poyang Lake

作　　者：付超 谌芸 尹丝雨[1,2] 曾智琳 单九生 朱克云 FU Chao;CHEN Yun;YIN Siyu;ZENG Zhilin;SHAN Jiusheng;ZHU Keyun(Fujian Meteorological Observatory,Fuzhou 350001;Fujian Key Laboratory of Severe Weather,Fuzhou 350001;National Meteorological Centre,Beijing 100081;College of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610225;School of Atmospheric Sciences,Sun Yat-Sen University,Zhuhai 519082;Jiangxi Meteorological Observatory,Nanchang 330096)

机构地区：[1]福建省气象台,福州350001 [2]福建省灾害天气重点实验室,福州350001 [3]国家气象中心,北京100081 [4]成都信息工程大学大气科学学院,成都610225 [5]中山大学大气科学学院,珠海519082 [6]江西省气象台,南昌330096

出　　处：《气象》2021年第1期24-35,共12页Meteorological Monthly

基　　金：国家自然科学基金项目(41975001、41175048);国家重点研发计划(2017YFC1502501)共同资助。

摘　　要：为量化分析研究湖泊对局地降水强度及性质的影响,基于WRF3.8版本中尺度数值模式及NCEP/NCAR提供的1°×1°时间间隔为6 h的FNL分析资料,进行控制性试验、湖泊陆面化的敏感性试验,对2011年6月14—15日鄱阳湖附近强降水的高值中心开展分析。结果表明:鄱阳湖水体下垫面白天作为“冷源”,对其附近100 km的水平范围、800 m的垂直厚度大气的温度有明显的“降温”调节作用。这种热力条件减弱影响了对流层中低层上升运动的强度与持续时间,造成降水强度减弱、降水时长缩短,最终减少了湖泊附近10%左右的累积雨量;鄱阳湖水体下垫面仅能提高边界层大气水汽的饱和程度(相对湿度),但“降低”了水汽的绝对含量(比湿),是湖泊陆面化后的敏感性试验比控制性试验降水中心强度更大、强降水范围更广的原因之一;湖泊水体下垫面通过“降低”边界层大气温度与绝对湿度,从而使大气具有比敏感性试验更弱的对流有效位能,大气低层(1000~850 hPa)具有更弱的对流不稳定度,探空反映控制性试验近地层有浅薄逆温结构,其比湖泊陆面化敏感性试验具有更低的CAPE,最终减弱控制性试验降水的对流性质。总体而言,鄱阳湖水体下垫面通过调节边界层大气的温度与绝对湿度,从而改变大气低层的环境条件,并影响初始抬升气块的温湿条件,延缓并减弱垂直运动的持续时间与强度,减弱湖泊附近低层的对流,对大气加热有45%的抑制率,最终减小降水强度与范围。In order to quantitatively analyze the influence of lake on the intensity and properties of precipitation,this paper designes the control experiment and the sensitivity experiment of lake land-surface,based on the mesoscale numerical model of WRF3.8 version and the NCEP/NCAR FNL 1°×1°analysis data with time interval of 6 h.The high value center of heavy precipitation near Poyang Lake from 14 to 15 June 2011 is analyzed.The results show that the surface of Poyang Lake is a“cold source”during the day,which has obvious“cooling”regulation effect on the horizontal range of 100 km and the vertical range of 800 m.This weakening of thermal conditions affects the intensity and durability of the vertical upward motion in the middle and lower troposphere,resulting in reduced precipi-tation intensity and shorter precipita-tion duration,which ultimately reduces about 10%of accumulated rainfall near the lake.The underlying surface of Poyang Lake can only improve the saturation degree(relative humidity)of atmospheric water vapor in the boundary layer,but“reduce”the absolute content of water vapor(specific humidity),which is one of the reasons why the sensitivity experiment rather than control experiment precipitation center has greater strength and a wider range of heavy precipitation after lake land-surface.The lower surface of the lake water body results from reducing the atmospheric temperature and absolute humidity of the boundary layer so that the atmosphere has a weaker convection effective potential energy than sensitivity experiment,and the lower atmosphere(1000-850 hPa)has a weaker convection instability.Sounding reflects the control experiment near the formation has a shallow inverse temperature structure.It has a lower CAPE than the lake terrestrial sensitivity experiment,and finally weakens the convection properties of the control experiment precipitation.Generally speaking,the underlying surface of Poyang Lake changes the temperature and absolute humidity of the boundary layer,thus changing the envir

关 键 词：湖泊陆面化 减弱强降水 热力与湿度条件 对流稳定度 

分 类 号：P435[天文地球—大气科学及气象学]