吉林省夏季降水时空变化特征研究

根据吉林省46个气象站1961-2010年夏季6-8月降水资料,采用线性趋势估计、旋转经验正交函数(REOF)等方法,对吉林省夏季降水的空间分布结构和长期变化特征进行了分析.得到如下结论:(1)近50 a吉林省夏季降水整体有减少的趋势,但未能通过显著性检验；从1980s初期开始,夏季极端旱涝事件发生频率有增大趋势,旱涝交替变化更加频繁；在降水异常的背景下吉林省大部分地方的暴雨发生频率呈增多趋势；(2)采用REOF客观的数学方法得到吉林省夏季降水的3个气候分区,即西北部平原区、中南部区和东部山区,这3个分区较好地反映了夏季降水的地域差异分布特征；(3)吉林省3个降水气候区分别呈现不同的降水趋势变化,西北部平原区降水趋势减少导致干旱发生概率增大,中南部区降水趋势增加导致洪涝发生概率增大,东部山区降水稳定少变.

Analysis of spatial and temporal variation characteristics of summer precipitation in Jilin province

By using the summer precipitation data of 46 observational stations from 1961 to 2010,the spatial distribution characteristics and temporal variation trend of summer precipitation in Jilin province are analyzed with the Linear Trend Estimation and Rotated Empirical Orthogonal Function(REOF) methods. The results show as follows: (1) the summer precipitation shows a decreasing trend, which hasn't passed the significance test in recent 50 a. An increasing tendency with more frequent alternation between drought and flood has existed in the frequent summer extreme events of drought and flood from early 1980s. The summer rainstorm frequency in the most areas shows a slightly increasing tendency in the context of precipitation anomalies. (2) By objective mathematical method of REOF, summer precipitation in Jilin province is divided into three climatic regions: the northwest plain area, the south-central area and the east mountain area, all of which basically reflect the geographical distribution characteristics of summer precipitation variation. (3) The three climatic regions show different tendency in summer precipitation, that is, a decreasing trend of precipitation leads to increased probability of drought in the northwest plain area, an increasing summer precipitation results in increased probability of flood in the south-central valley area and less variable summer precipitation in the east mountain area.