四川温江有无雨日的边界层特征对比分析  

A Comparative Analysis of Boundary Layer Characteristics in Rainy and Rainless Days at Wenjiang,Sichuan Province

作　　者：卢萍[1,2] 李英 LU Ping;LI Ying(Institute of Plateau Meteorology,CMA,Chengdu 610072,China;Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu 610072,China)

机构地区：[1]中国气象局成都高原气象研究所,四川成都610072 [2]高原与盆地暴雨旱涝灾害四川省重点实验室,四川成都610072

出　　处：《沙漠与绿洲气象》2020年第1期80-88,共9页Desert and Oasis Meteorology

基　　金：国家自然科学基金项目(41405145);成都高原气象研究所开放实验室基金项目(BROP201714)。

摘　　要：基于2016年6月21日—7月31日温江站边界层塔和加密探空观测获取的资料,对比分析了该站有雨日和无雨日的边界层大气特征,得到以下结论:(1)温江站7月的降水量较多,降水时段以凌晨2—6时居多,呈现典型的“夜雨”特征。(2)探空观测资料揭示:无雨日白天边界层呈现典型的混合边界层特征。有雨日边界层大气温度总是小于无雨日,在极大值出现的午后时段二者的差值最大,云作用使得无雨日的底层逆温现象在有雨日呈现为近似恒温现象。有雨日近地层大气比湿日变化幅度低于无雨日,其日变化主要受湍流运动和辐合输送的影响。温江站边界层低层大气的风速总体较小,有雨日的风速明显大于无雨日,且风向更有利于产生降水。(3)边界层塔观测显示:有雨日太阳短波辐射以及各个地表通量的极大值仅为无雨日的2/3左右。白天,有雨日的温度低于无雨日,日变化幅度比无雨日低3℃左右;夜间二者都呈现显著的逆温现象。有雨日白天湿度高于无雨日,夜间则低于无雨日,有雨日湿度日变化幅度比无雨日少2 g/kg;白天,有雨日风速日变幅也略小于无雨日,除了午后时段,有雨日在凌晨2时还出现另外一个风速极大值;有雨日的气压值总是略高于无雨日,白天的气压差值比夜间大。白天,有雨日各个地面观测量的极值出现时间总是比无雨日滞后1 h左右。The characteristics of boundary layer in rainy and rainless days from 21 June to 31 July in 2016 are comparatively analyzed based on the observational data of boundary layer tower and intensive sounding at Wenjiang site,The results showed that:(1)Wenjiang Station has a large amount of precipitation in July,and the precipitation period is during 2:00-6:00 in the morning,presenting typical night rain.(2)Based on lower atmosphere sounding data,it presents typical mixed boundary layer in daytime in rainless days.Temperature in the boundary layer is smaller in rainy days than in rainless days,and the maximum difference appears in the afternoon.Cloud action makes the bottom inversion of rainless days appear as approximate constant temperature phenomenon on rainy days.Daily changing amplitude of specific humidity in rainy days is smaller than that in rainless days.It is diurnal variation is mainly affected by turbulent motion and convergence transport.Wind speed is small in lower boundary layer,but it is obviously bigger in rainy days than in rainless days,and the wind direction is more conducive to precipitation.(3)The maximum values of solar radiation and surface fluxes in rainy days are only about two-thirds of those in rainless days.During the daytime,the temperature of the rainy days is lower than in rainless days,and its daily changing amplitude is about 3℃than in rainless days.There is remarkable inverse humidity both in rainy and rainless days at night.Specific humidity in rainy days is bigger than in rainless days in the daytime,while lower at night.The daily change amplitude of specific humidity in rainy days is less 2 g/kg than in rainless days.The daily changing amplitude of wind speed in rainy days is slightly less than in rainless days.Except in the afternoon,another maximum of wind speed occurs in 2:00 in rainy days.Pressure value in rainy days is slightly higher than in rainless days,and its difference is bigger in the daytime than at night.Maximum value of each observational element in the surface lay

关 键 词：边界层 探空 有雨日 无雨日 日变化 极值 

分 类 号：P421.3[天文地球—大气科学及气象学]