祁连山及周边地区降雪气候特征研究  

Climate Characteristics of Snowfall over the Qilian Mountain and Its Ambient Areas

作　　者：李岩瑛[1,2,3] 张强[1,3] 孙爱芝[4] 张义海 李玲萍 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃省干旱气候变化与减灾重点实验室,甘肃兰州730020 [2]甘肃省武威市气象局,甘肃武威733000 [3]兰州大学大气科学学院,甘肃兰州730000 [4]西南大学地理科学学院,重庆400715

出　　处：《冰川冻土》2008年第3期383-391,共9页Journal of Glaciology and Geocryology

基　　金：国家科技攻关计划“西部开发科技行动”重大项目“祁连山空中云水资源开发利用研究”(2004BA901A16)资助

摘　　要：利用祁连山区及其周边地区（90°～104°E，32°～42°N）1960-2004年55个站点冬季逐日降水资料，重点分析了祁连山区（94°～104°E，36°～39°N）不同降雪强度的时空分布特征，暴雪的天气影响系统及地形作用．结果表明：祁连山区降雪量与中雪日数关系最密切，祁连山东北侧降雪日数最多．祁连山不同区域分布中西部雪日最少，中部强度最弱；小雪中部最多，中雪中南部较多较强，大到暴雪北侧最多、南侧最强．降雪夜间明显较多，小到中雪强度夜间较强；年变化在西部持续增多，中部70年代最少，北侧90年代最少；但西中北部均21世纪最多，南侧70年代最多，之后持续减少．降雪日数有3～4a、5～7a和12～14a的年际变化周期．暴雪出现的主要天气环流形势为北方横槽南压型和新疆冷温槽发展东移型，分别占38．1％和52．4％．暴雪均出现在山脉冬季风的迎风坡和峡谷地带．Daily snowfall data of nighttime （20pm -08am）, daytime （08am-20pm） and full day （20pm-20pm） during winter （from November to February） from 1960 to 2004 from 55 meteorological stations in the Qilian Mountain and ambient areas（90°-104° E, 32°-42° N）are analyzed for the temporal and spatial distribution characteristics of various snowfall intensities, snowstorm weather impact systems and terrain influence. It is found that in the Qilian Mountain the number of middling snowfall days is most correlated to snowfall, with a correlation coefficient of 0. 87 and the most snowfall days occurring in northeast. In various regions the least snowfall days appear in the west, the least intensity appears in the middle, but the most flurry days appear in the middle, middling snowfall is more and stronger in the middle and south, heavy snow and snowstorm are most in the north, and the most strong ones in the south. Nighttime snow days are more obviously, nighttime flurry and middling snowfall are stronger than those in daytime. As to annual variation, the annual snowfall is increasing continuously in the west, the least snow occurred in the 1970s in the middle areas and in the 1990s in the north, but the most occurred in the 21 century in the west, north and middle, a peak occurred in the 1970s in the south, and then was decreasing continuously. In the inter-annual variation, there are obvious periods of 3-4 years, 5-7 years and 12-14 years for the snowfall days. The primary weather backgrounds of snowstorm are types of north horizontal trough pressing southwards and type of Xinjiang cold trough developing and moving eastwards, account for 38. 1% and 52. 4%, respectively. All snowstorms occurred in the mountain windward slopes of winter monsoon and gorges.

关 键 词：冬季降雪 时空分布 暴雪特征 祁连山区 

分 类 号：P467[天文地球—大气科学及气象学]