摘要
利用1988—2018年藏北各站逐日降水资料、逐日天气现象和逐日积雪资料,用气候诊断和小波分析等方法分析了藏北暴雪天气的气候特征。结果表明,近31年藏北暴雪日数、雪量、最大积雪深度和年平均积雪深度的空间分布总体上呈东部多、西部少的趋势,主要集中在东部,区域差异显著。近31年的暴雪次数和暴雪量呈减少趋势,暴雪次数和雪量由多转少的转折年份在2002年,2002年以前为多雪期,2002年以后为少雪期。21世纪00年代后暴雪次数每10年以2站次的速率在下降,暴雪量以每10年2.4 mm的雪量在减少。暴雪季节分布呈双峰性,最大峰值出现在4月和5月。暴雪日数呈3、5、10年的周期变化。利用NCEP再分析资料的高度场和风场对暴雪天气的环流和影响系统进行了总结归纳,得出藏北区域性暴雪的环流形式可分为4型,即印度低压型、北脊南槽型、阶梯槽型和巴尔喀什湖低槽型;南支槽、热带低压、低涡-切变和高原槽为藏北暴雪天气的主要影响系统。
Using the daily precipitation data,weather phenomena,and snow accumulation data of observatories in northern Tibet from 1988 to 2018,the climatic characteristics of snowstorms in the northern Tibet were analyzed by methods of meteorological diagnosis and wavelet analysis.The results showed that the spatial distribution of the number of snowstorm days,snow amount,maximum snow depth and annually average snow depth in the northern Tibet in the past 31 years generally showed a trend of more in the east than in the west,mainly concentrated in the east,with a significant regional difference.The number of the snowstorm and the amount of snow in the last 31 years showed a decreasing trend.The turning year of which was 2002,it was a snowy period before 2002,and it was a pe⁃riod of few snowfalls after 2002.After the 2000s,the number of snowstorms decreased at a rate of 2 stops every 10 years,and the amount of snowstorms decreased at a rate of 2.4 mm per 10 years.The season distribution of the snowstorm was bimodal,with the larg⁃est peaks occurring in April and May.The number of snowstorm days showed a periodic change of 3a,5a,and 10a.Using NCEP to an⁃alyze the height field and wind field of the data,the circulation and impact system of snowstorm weather were summarized and conclud⁃ed.The circulation pattern of the regional snowstorm in north Tibet could be divided into 4 types,namely,the Indian low-pressure type,the north ridge&south trough type,stepped trough type,and Balkhash lake low trough type.The southern branch trough,tropi⁃cal depression,low vortex-shear and plateau trough were the main influence systems of the snowstorm in the northern Tibet.
作者
余燕群
熊秋芬
卓玛
德吉白珍
YU Yan-qun;XIONG Qiu-fen;Zuoma;De Ji Baizhen(Meteorological Observatory of Tibet Autonomous Region,Lhasa 850000,China;China Meteorological Administration Training Centre,Beijing 100081,China)
出处
《湖北农业科学》
2020年第17期31-37,共7页
Hubei Agricultural Sciences
关键词
暴雪
小波分析
气候特征
环流分型
藏北
snowstorm
wavelet analysis
climatic characteristics
circulation type
northern Tibet
