闽南沿海2018-2019年季风爆发前后雨滴谱特征对比分析  

Comparative analysis of raindrop size distribution characteristics before and after monsoon onset in southern coast of Fujian province in 2018-2019

作　　者：胡雅君 张伟 张玉轩 温龙[5] HU Yajun;ZHANG Wei;ZHANG Yuxuan;WEN Long(Xiamen Key Laboratory of Strait Meteorology,Xiamen 361012,China;Fujian Key Laboratory of Severe Weather,Fuzhou 350001,China;Xiang'an Meteorological Bureau,Xiamen 361103,China;Xiamen Meteorological Observatory,Xiamen 361012,China;Xichang Satellite Launch Center,Xichang 615000,China)

机构地区：[1]厦门市海峡气象开放重点实验室,厦门361012 [2]福建省灾害天气重点实验室,福州350001 [3]翔安区气象局,厦门361103 [4]厦门市气象台,厦门361012 [5]西昌卫星发射中心,西昌615000

出　　处：《气象学报》2022年第4期618-631,共14页Acta Meteorologica Sinica

基　　金：国家自然科学基金项目(41905021);国家自然科学基金青年基金项目(41805028);福建省灾害天气重点实验室重大科技专项(2020BY08)。

摘　　要：为研究华南前汛期季风爆发前后闽南地区的雨滴谱特征差异,利用2018—2019年厦门站和同安站4—6月的降水现象仪资料,对比分析了季风爆发前后闽南沿海层状云和对流云的雨滴谱分布及微物理参数差异。结果表明,华南前汛期闽南沿海层状云降水占比明显高于对流云降水,但对流云降水的滴谱分布更宽,峰值粒径以上的各粒径区间粒子浓度均大于层状云降水。不论层状云或是对流云降水,2018年季风爆发后均表现为质量加权平均直径(D_(m))减小,广义截距参数(N_(w))增大。2019年季风爆发后D_(m)增大,层状云的N_(w)减小,对流云N_(w)增大。两年整体呈现相反的演变趋势。层状云的降水率(R)和液态水含量(W)的演变趋势与N_(w)一致,而对流云的R和W与D_(m)一致。闽南沿海雨滴谱微物理参数接近于华南沿海,与华东区域相比,整体浓度更高,粒子尺度略小。Z-R关系拟合表明季风爆发前、后层状云与对流云的拟合系数、决定系数具有较大差异,其中对流云拟合效果相对更好。基于Z=300R^(1.4)的定量降水估测对层状云降水和量级较小的对流云降水整体上存在不同程度的低估,对于量级较大的对流云降水存在高估。探讨了环流形势对雨滴谱的可能影响。结果表明绝对水汽含量可能会影响粒子数浓度,而西南风等动力条件和对流有效位能等热力条件会通过影响对流的高度和降水的微物理过程进而可能会影响雨滴谱分布。Observations collected by precipitation phenomenometers at Xiamen and Tong’an stations from April to June in 2018 and 2019 are used to analyze differences in drop size distribution(DSD)and microphysical parameters before and after the monsoon onset in the pre-flood season in southern coast of Fujian.The results show that the frequency of stratiform precipitation is significantly higher than that of convective precipitation.The spectrum width of convective precipitation is much larger than that of stratiform precipitation in every interval above the peak value.Variations of the mass-weighted mean diameter(D_(m))and the generalized intercept parameter(N_(w))have opposite trends in 2018 and 2019.D_(m)decreased while N_(w)increased for both stratiform and convective precipitation after the monsoon onset in 2018.However,D_(m)increased and N_(w)of stratiform precipitation decreased while that of convective precipitation increased after the monsoon onset in 2019.Rain rate(R)and liquid water content(W)are consistent with N_(w)for stratiform precipitation,while R and W are consistent with D_(m)for convective precipitation.Microphysical parameters in southern coast of Fujian show consistent features with those in southern coast of China,while the particle number concentration is higher but the particle size is smaller compared with those in eastern China.The coefficient of Z-R relationship varies significantly for stratiform and convective precipitation with better fitting effect for convective precipitation.QPE based on Z=300R^(1.4) relationship probably would underestimate stratiform or weak convective precipitation,but most likely overestimates strong convective precipitation.Circulation influence on DSD is discussed.Results indicate that specific humidity can affect particle concentration.Dynamic condition such as southwesterly winds and thermal condition such as CAPE can affect DSD through convection height and microphysical processes of precipitation.

关 键 词：季风爆发 雨滴谱 Z-R关系 

分 类 号：P426.61[天文地球—大气科学及气象学]