Journal of Arid Meteorology

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Application of Wind Profiler Radar Data in a Heavy Precipitation Process in Central Hebei Province

XU Min 1, ZHANG Yu2, ZHANG Shaohui1   

  1. 1. Langfang Meteorological Bureau of Hebei Province, Langfang 065000, China;
    2. Wen’an Meteorological Station of Hebei Province, Wen’an 065800, China
  • Online:2016-11-01 Published:2016-11-01

风廓线雷达资料在冀中一次强降水天气预报中的应用

许敏1张瑜2张绍恢1   

  1. 1.河北省廊坊市气象局,河北廊坊065000;2.河北省文安县气象局,河北文安065800
  • 作者简介:许敏(1983-),女,内蒙古包头市人,工程师,主要从事天气预报与决策服务工作. E-mail:hblfxm@163.com
  • 基金资助:

    河北省气象局科研开发项目“基于两种非常规资料的强降水短临预报研究”(15zc01)、廊坊市科技局项目“廊坊短时强降水预报预警技术研究”(2015013015)和廊坊市气象局自立课题“廊坊市雾霾、强降水的风廓线雷达特征研究”(201501)共同资助

Abstract:

Based on convertional weather stutions, automatic weather station, wind profiler radar data and NCEP reanalysis data, a short-time heavy rainfall occurring between Beijing and Tianjin on 30 July 2015 was analyzed, and the atmospheric wind field characteristics before precipitation was focused on. The results were summarized as follows:(1) Low-level jet appeared nearly two hours before the heavy rain, which not only provided sufficient moisture for outbreak of the short-time strong rainfall, but also established the convective instability stratification under 700 hPa and triggered the instability energy releasing.(2)The updraft appeared above 1 000 m about 90 minutes before the heavy rain , then its height was falling and thickness was increasing, and after 30 minutes, it achieved the most powerful. As the precipitation was near, the updraft began to weaken, and when the precipitation started, the sinking airflow rapidly occupied a dominant position. (3)Cold advection formed in the boundary layer 70 minutes before the heavy rain, and warm moist air flows climbed on it, which gathered water vapor and energy, and cold air on middle level began to invade and developed strongly. (4)The variation of low-level jet had close relationship with occurrence of heavy rain, but the change of rainfall intensity was not only associated with low-level jet, but also it was the result of joint action of water, power and thermal conditions.(5)  The water, power and thermal conditions accumulated and strengthened before precipitation occurrence, and this strong signal was generally in advance 60 to 120 minutes, which provided scientific basis for heavy rain nowcasting.

Key words: short-time strong rainfall, wind profiler radar data, wind field

摘要:

通过运用常规气象站、自动站、风廓线雷达资料和NCEP(1°×1°)再分析资料对2015年7月30日出现在京津之间的一次短时强降水天气进行综合诊断,特别是深入分析了降水开始前大气的风场特征。结果表明:(1)低空急流在强降水开始前2 h左右出现,其不仅为短时强降水的爆发提供充足水汽,同时也是700 hPa以下对流不稳定层结的建立者和不稳定能量释放的触发者;(2)强降水发生前约90 min在1 000 m高度以上出现上升气流,此后其所在最低高度下降,厚度增加,30 min后上升气流达到最强盛;随着降水的临近,上升气流开始减弱,降水开始后,下沉气流迅速占据绝对主导地位;(3)强降水发生前70 min边界层有冷平流形成,西南暖湿气流在其上爬升,使得水汽和能量积聚,中层冷空气开始楔入并发展强盛,表明冷暖空气强烈交绥,同时能量释放;(4)低空急流指数的脉动虽与强降水的发生有密切关系,但并不是高指数就一定会出现强降水,雨强的变化除了与低空急流有关,还与水汽、动力以及热力等多种因素相关,是一种综合条件共同作用的结果;(5)强降水形成所需的水汽、动力、热力等条件均在降水出现前积累加强,这种强烈的信号一般提前60~120 min达到极致,为强降水的临近预报提供了科学依据。

关键词: 短时强降水, 风廓线雷达, 风场特征

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