主办单位：中国气象局沈阳大气环境研究所
国际刊号：ISSN 1673-503X
国内刊号：CN 21-1531/P
气象与环境学报

气象与环境学报 ›› 2016, Vol. 32 ›› Issue (5): 1-9.doi: 10.3969/j.issn.1673-503X.2016.05.001

• 论文 •    下一篇

2014年杭州地区一次雨转雪天气过程分析

李进1, 陈练2   

  1. 1. 杭州市气象局, 浙江 杭州 310051;
    2. 浙江省气候中心, 浙江 杭州 310002
  • 收稿日期:2015-07-27 修回日期:2015-10-12 出版日期:2016-10-31 发布日期:2016-10-31
  • 作者简介:李进,女,1987年生,工程师,主要从事天气预报、气候诊断分析及预测研究,E-mail:li.jin8719221@163.com。
  • 基金资助:

    浙江省青年科学基金项目（Q14D050002）和浙江省气象科技计划项目（2014ZD06-4）共同资助。

Analysis of weather process of rain to snow in Hangzhou region in 2014

LI Jin1, CHEN Lian2   

  1. 1. Hangzhou Meteorological Service, Hangzhou 310051, China;
    2. Zhejiang Province Climate Center, Hangzhou 310002, China
  • Received:2015-07-27 Revised:2015-10-12 Online:2016-10-31 Published:2016-10-31

PDF (PC)

441

被引次数

1

摘要：

利用NCEP 1°×1°再分析资料、常规气象观测资料、降雪加密观测资料和卫星云图资料，对2014年2月17-19日杭州地区一次雨转雪天气过程进行了分析。结果表明：500 hPa南支槽、700 hPa和850 hPa切变线，配合700 hPa西南急流，为杭州地区此次雨转雪天气过程提供了较好的动力抬升和水汽条件；而700 hPa暖湿气流与850 hPa不断增强的东北气流，又为此次雨转雪天气过程提供了上暖下冷的有利层结条件。此次雨雪天气过程水汽通量与降水时段和降水强度对应。整个雨转雪天气过程中对流层均以垂直上升运动为主，相对湿度均较大，且降水不同阶段均存在水汽辐合；液态降水时，对流层中低层为水汽辐合层和上升运动层，且中层存在辐散抽吸作用，此配置有利于产生降水；而当降雪时，中低层的水汽辐合与垂直上升速度逐渐减小，此时以中层的水汽辐合和上升运动为主。雨雪强度减弱时，水汽辐合也减弱直至消失，且中低层和中层的上升速度均逐渐减弱，在600 hPa附近出现弱下沉运动和相对湿度迅速减小的现象，但中低层一直维持弱的上升运动与较大的相对湿度，直至19日凌晨雨雪过程才结束。由于此次雨转雪天气过程冷空气较弱，地面温度相对较高，因此降水量虽然较大，但积雪率较低。

关键词: 雨转雪, 抽吸作用, 上升运动, 相对湿度, 地面温度

Abstract:

Based on the NCEP (National Centers for Environmental Prediction)reanalysis data with resolutions of 1°×1°,conventional meteorological data,intensive snowfall observations as well as satellite cloud images,the weathering process of rain to snow in Hangzhou region on February 17-19,2014 was analyzed.The results indicate that the southern branch trough at 500 hPa,shear lines at 700 hPa and 850 hPa,as well as the southwesterly jet stream at 700 hPa,provide favorable conditions for dynamic lifting and water vapor supplement during this weathering process.Additionally,warm and humid airflow at 700 hPa and continuously strengthening northeasterly flow at 850 hPa make favorable stratification conditions with warm air at upper levels and cold air at lower levels.Water vapor flux is related to the period and intensity of precipitation during the rain-snow process,and ascending motion exists in the whole troposphere.High relative humidity and convergence of water vapor show in different stages of the weathering process.When liquid precipitation occurs,it is accompanied by water vapor convergence and ascending motion in the middle and lower troposphere as well as suction effect in the middle troposphere,which is favorable for precipitation.However,when rain turns into snowfall,the water vapor convergence and ascending motion decrease gradually in the middle and lower troposphere but still maintain in the middle troposphere.Water vapor convergence is weakening and even disappears with the declining intensity of rain and snowfall,and the ascending motion at the mid-lower and middle levels also decreases gradually,accompanied by weak descending motion and rapidly decreasing relative humidity near 600 hPa.However,weak ascending motion and large relative humidity remain in the middle and lower troposphere until the snow has stopped in the morning on February 19.Due to the weak activity of cold air and high surface temperature during the process of rain turning into snow,the snow cover rate is small in spite of large precipitation and snowfall.

Key words: Rain to snow, Suction effect, Ascending motion, Relative humidity, Surface temperature

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