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湖泊对局地强降水“弱化”作用的数值模拟研究
付超1, 谌芸2, 曾智琳3, 单九生4, 朱克云3
(1.福建省气象台;2.国家气象中心;3.成都信息工程大学大气科学学院;4.江西省气象台)
Numerical Simulation of the Lake Weakening on Local Heavy Precipitation
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投稿时间:2019-10-13    修订日期:2020-06-01
中文摘要: 为量化分析研究湖泊对局地降水强度及性质的影响,本文基于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(HL)试验、湖泊陆面化的敏感性(NL)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:(1)鄱阳湖水体下垫面作为“冷源”,对其附近100 km的水平范围、500 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垂直上升运动的强度与持久度,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。(2)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NL比HL试验降水中心强度更大、强降水范围更广的原因之一。(3)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NL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HL试验近地层有浅薄逆温结构,其比湖泊陆面化NL试验具有更低的CAPE,最终“弱化”HL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,最终影响降水性质与强度。
Abstract:In order to quantitatively analyze and study the influence of lake on the intensity and properties of precipitation, this paper designed the control (HL) experiment and the sensitivity (NL) experiment of lake land-surface, it based on the mesoscale numerical model of WRF3.8 version and the FNL analysis data of with the 1°×1°, time interval is 6 h provided by NCEP/NCAR. The high value center of heavy precipitation near Poyang Lake on 14 to 15, June, 2011 was analyzed. The results show that: (1) The surface of Poyang Lake is a "cold source", which has obvious "cooling" regulation effect on the horizontal range of 100 km and the vertical range of 500 m. This weakening of thermal conditions affects the intensity and durability of the vertical upward motion in the troposphere, resulting in reduced precipitation intensity and shorter precipitation duration, which ultimately reduces the about 10% of accumulated rainfall near the lake. (2) The lower cushion 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 (compared with wet), which is one of the reasons why the NL than HL experiment precipitation center has greater strength and a wider range of heavy precipitation after lake land surface. (3) The lower surface of the lake water body by reducing the atmospheric temperature and absolute humidity of the boundary layer, so that the atmosphere has a weaker convection effective potential energy than NL, the lower atmosphere (1000~850 hPa) has a weaker convection instability, sounding reflects the HL test near the formation has a shallow inverse temperature structure, It has a lower CAPE than the lake terrestrial NL experiment, and finally weakens the convection properties of the HL test precipitation. Generally speaking, the lower surface of Poyang Lake changes the temperature and absolute humidity of the boundary layer, thus changing the environmental conditions of the lower atmosphere, and affecting the temperature and humidity conditions of the initial uplift gas block, which ultimately affects the precipitation properties and strength.
文章编号:201910130372     中图分类号:    文献标志码:
基金项目:(41975001、41175048),国家重点研发计划专项项目(2017YFC1502501)共同资助
引用文本:
付超,谌芸,曾智琳,单九生,朱克云,0.[en_title][J].Meteor Mon,():-.
fuchao,chenyun,zengzhilin,shanjiusheng,zhukeyun,0.Numerical Simulation of the Lake Weakening on Local Heavy Precipitation[J].Meteor Mon,():-.