欧亚大陆积雪与2010年中国春末夏初降水的关系  

Relationship between Eurasian Snow Cover and Late-Spring and Early-Summer Rainfall in China in 2010

作　　者：许立言[1,2] 武炳义[1] 

机构地区：[1]中国气象科学研究院,北京100081 [2]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《高原气象》2012年第3期706-714,共9页Plateau Meteorology

基　　金：国家自然科学基金项目(40921003;40875052);中国气象局行业专项项目(GYHY200906017);国家重点基础研究发展规划项目(2007CB411505)共同资助

摘　　要：利用欧亚大陆地区的积雪覆盖日数资料、中国160个台站逐月降水资料以及美国国家环境预报中心和国家大气研究中心(NCEP/NCAR)再分析资料,采用奇异值分解(SVD)方法和数值试验研究了欧亚大陆2-4月积雪与后期5-6月中国降水的关系。结合2010年积雪和降水的分布特征可以发现,SVD第二模态基本反映了2010年积雪异常与降水异常的时滞耦合关系。欧亚大陆积雪在欧洲、青藏高原东部和东亚地区异常偏多时,我国华南降水增多,长江中下游降水减少,欧亚大陆东、西部积雪异常偏多与后期中国华南降水存在正相关关系。根据统计分析得到的空间分布特征和积雪参数的观测数据,选用大气环流模式CAM3.1进行数值试验,模拟结果与统计分析结果比较一致。积雪异常通过反照率效应和水文效应引起地表及其上的大气热力状况异常,进而引起位势高度场、风场等各个大气环流要素场的调整,导致后期华南降水异常偏多。欧亚大陆积雪异常很可能是2010年春末夏初华南降水异常的一个重要诱发因子。The relationship between Eurasian snow cover anomalies from February to April and rain- fall from May to June of 2010 in China has been investigated using SVD analysis and numerical experiment, based on the datasets of snow cover days from NOAA, precipitation data at 160 stations and atmospheric circulation variation from the NCEP/NCAR reanalysis data in the period of 1973-2010. The second SVD mode properly represents the time and space characteristics of snow cover and rainfall in 2010： Exces sive snow cover in Europe, eastern Tibetan Plateau and East Asia tend to be associated with increased precipitation in South China and decreased precipitation in Central China. Snow cover in western and east ern Eurasia is positively correlated with succeeding precipitation in South China. Based on the statistical linkage, the impact of anomalous snow pattern on rainfall in South China is simulated using CAM3.1 mod- el. The result consists with the statistical fact. The physical mechanism between snow cover and rainfall is due to the albedo and hydrology action of snow cover, changing the thermal condition, which can modify the atmospheric general circulation and result in the abnormal rainfall of South China. Eurasian snow cov- er anomaly may be a major factor which forces late-spring and early-summer rainstorm in South China in 2010.

关 键 词：欧亚大陆积雪 中国春末夏初降水 SVD分析 数值试验 

分 类 号：P468.025[天文地球—大气科学及气象学]