Journal of Arid Meteorology ›› 2021, Vol. 39 ›› Issue (2): 279-287.DOI: 10.11755/j.issn.1006-7639(2021)-02-0279

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Vertical Characteristics of Raindrop Size Distribution During a Heavy Rain in Yining of Xinjiang Based on Micro-rain Radar Data

TONG Zepeng1,2, YANG Lianmei1,2, ZENG Yong1,2, LI Jiangang1,2, LIU Fan1,2   

  1. 1. Institute of Desert and Meteorology, China Meteorological Administration, Urumqi 830002, China;
    2. Center for Central Asia Atmosphere Science Research, Urumqi 830002, China
  • Online:2021-04-30 Published:2021-05-07

利用微雨雷达研究伊宁地区一次大雨过程的雨滴谱垂直演变特征

仝泽鹏1,2,杨莲梅1,2,曾勇1,2,李建刚1,2,刘凡1,2   

  1. 1.中国气象局乌鲁木齐沙漠气象研究所,新疆 乌鲁木齐 830002;
    2.中亚大气研究中心,新疆 乌鲁木齐 830002
  • 通讯作者: 杨莲梅(1969— ),女,研究员,主要从事灾害性天气研究. E-mail: yanglm@idm.cn。
  • 作者简介:仝泽鹏(1994— ),男,研究实习员,主要从事云降水物理天气研究.
  • 基金资助:
    国家重点研发计划项目(2018YFC1507102)、中央级公益性科研院所基本科研业务费专项资金项目(IDM2021002)和中国沙漠气象科学研究基金(Sqj2019003)共同资助

Abstract: A heavy rain process occurred in Yining of Yili valley on 30 September 2019. Based on the observation data of micro rain radar (MRR), terrestrial OTT-PARSIVEL raindrop spectrometer and rain gauge at Yining station, the reliability of MRR data was compared and tested. And on this basis, the vertical distribution characteristics of microphysical quantities retrieved by MRR were investigated at different stages of the heavy rain process. The results show that the precipitations from three kinds of instruments were close, and their change trends were consistent. The rainfall intensity of MRR near ground level (35, 70 and 105 m) had a good correlation with the observation of OTT-PARSIVEL raindrop spectrometer, the coefficients were 0.9233, 0.9289 and 0.9186, respectively, and the convergence degree of rainfall intensity between two kinds of instruments was higher when the rainfall intensity was less than 3 mm·h-1. The vertical distributions of microphysical quantities from MRR were different at different stages of rainfall intensity. At the low rainfall intensity stage, the environmental humidity was lower and evaporation was stronger during the initial period of rainfall, the radar reflectivity factor, liquid water content and rain intensity from MMR decreased with decrease of height, while the environmental humidity was higher and evaporation was weaker during the middle period of rainfall, and the vertical changes of radar reflectivity factor, liquid water content and rain intensity weren’t obvious. During the late period of rainfall, the rain intensity near ground decreased significantly under the low rainfall intensity condition because the supply of water vapor and power was lack. At the moderate and high rainfall intensity stages, the vertical distribution of particles falling velocity was stable, while the radar reflectivity factor, liquid water content and rain intensity increased with decrease of height due to the collision and merger interaction between raindrops. The small raindrops dominated during the heavy rain process in Yining, the percentage of average number concentration of small raindrops to total number concentration exceeded 90%, and it decreased with decrease of height. The contribution of medium raindrops to total rain intensity was the greatest, the contribution rates at different stages of rainfall intensity were 60% and above, and it increased with decrease of height. The number concentration of large raindrops was the smallest in proportion of total number concentration, and its contribution to total rain intensity was the smallest.

Key words: micro rain radar, raindrop-size distribution, micro-physical quantities, vertical distribution

摘要: 基于伊犁河谷伊宁站内布设的微雨雷达(MRR)、地面OTT-PARSIVEL雨滴谱仪以及雨量筒观测资料,针对2019年9月30日伊宁地区一次大雨过程,对比检验MRR数据的可靠性,在此基础上探究降水不同时期MRR的微物理量垂直分布特征。结果表明:3种仪器观测的降水量较为接近、变化趋势一致,MRR观测的近地面35、70和105 m高度层雨强与OTT-PARSIVEL雨滴谱仪的观测值有较好的相关性,决定系数分别为0.9233、0.9289和0.9186,且当雨强低于3 mm·h-1时,MRR与雨滴谱仪的雨强拟合收敛程度更高。不同雨强阶段,雨滴谱的垂直分布存在差异。低雨强阶段,降水初期环境湿度较低、蒸发较大,MRR的雷达反射率因子Z、液态水含量LWC及雨强Ri随高度降低而减小;降水中期,环境湿度较大、蒸发较小,Z、LWC、Ri随高度变化不大;降水末期,空中水汽和动力条件供应不足,靠近地面Ri明显减弱。中、高雨强阶段,粒子下落速度W较为稳定,而Z、LWC、Ri受雨滴间碰并作用影响较大,整体随高度降低而增大。此次大雨过程主要以小雨滴为主,其平均数浓度占总数浓度90%以上,且随高度降低而减少;中雨滴对雨强的贡献最大,不同雨强阶段的贡献率均在60%以上,且随高度降低而增大;大雨滴数浓度占比及对雨强的贡献均最小。

关键词: 微雨雷达, 雨滴谱, 微物理参量, 垂直分布

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