东北地区冬季降雪的气候特征及其区划

根据东北地区197个气象观测站1961-2006年冬季(12-2月)的逐日降雪量资料,采用线性趋势、小波分析、突变分析、t-检验、EOF(经验正交函数)、REOF(旋转经验正交函数)和CAST(聚类统计检验)等气候统计方法,对东北地区近45a来冬季降雪的气候特征进行了研究.结果表明:东北地区近45a冬季降雪呈下降趋势,每10a下降0.2mm.降雪具有明显的阶段性,1960年代中期到1970年代中期为偏少时段,1970年代中期以后到1980年代中期为偏多时段,1980年代中期至1990年代降雪基本持平,在2000年之后降雪量有所增加.东北地区冬季降雪在45a间始终存在着10a左右的长周期,1980年代以后存在着6a左右的周期,而在1970-1980年代和1990年代之后存在着4a的短周期.EOF分析结果表明:全区一致由北向南的正变化趋势为主要模态,大值区主要位于吉林东部和辽宁西北部,西北-东南反向变化,黑龙江北部同其它区域表现出反向变化特征,也是重要的异常模态.REOWCAST方法的区划表明:东北地区降雪主要分为4个区域,分别为辽宁-吉林东部、吉林北部-黑龙江南部、辽宁西南部和黑龙江北部地区,不同区域降雪量的变化趋势存在差异.

Climatic characteristics and regionalization of winter snowfall in Northeast China

Based on the winter(December to February) daily precipitation data in 1961 -2006 from the 197 meteorological observation station, using a series of climatic statistical analysis method, such as linear trend, wavelet a-nalysis, abrupt change analysis, t-test, EOF, REOF, CAST clustering method, the temporal and spatial distribution and the regionalization of winter snow was researched for the Northeast area in past 45 years. The result shows that: winter snow reveals decreasing trend in the past 45 years as a whole in Northeast region, with rate of -0. 22mm/10a. The amount of snow is distinct in different stages, I. E. On the less side from mid-1960s to mid-1970s, on the much side from 1975 to the middle of 1980s ,on the normal level from the middle of 1980s to 1990's,and on the increasing, state after 2000. There is always about 10 years of long-period for winter snowfall in Northeast region during the past 45 years, after the 1980s there is a cycle of 6 years or so, and in 1970 -1980 and after the 1990s there is a short 4 year cycle. There is the same positive change trend in the whole region from north to south as the main mode, high value districts are mainly located in the east part of Jinlin and the northwest part of Liaon-ing. The variation in northwest region is opposite to that in southeast region. Compared with the other region, the northern part of Heilongjiang Province shows reverse changes which is an important anomaly mode. REOF/CAST a-nalysis shows that winter snowfall in Northeast China is divided into four spatial regions with different change trend, I. E. Liaoning-the east part of Jilin, the north part of Jilin-the south part of Heilongjiang and the southwest part of Liaoning, and the north part of Heilongjiang.