西南地区夏半年降水的多时空尺度特征

根据国家气象中心提供的西南地区夏半年月降水资料,利用旋转经验正交函数(REOF)展开方法,将西南地区划分为川西北、川渝区、云川区和贵州区4个区域,并在此基础上,利用多项式拟合趋势线、小波变换等方法,对各区域降水的变化特征进行了分析。结果表明,西南地区各区域降水的长期变化趋势不尽相同,川西北没有显著的趋势变化,川渝区表现为缓慢上升的趋势,而云川区和贵州区则均表现为先下降后上升的趋势。西南地区各区域降水的周期特征也不尽相同,较短时间尺度的周期变化在西南地区各区域普遍存在;而较长时间尺度的周期,各个区域则有较大的差别,不仅表现在长时间尺度周期的显著性上,还表现在具有相同时间尺度周期,不同区域的干湿期配置等方面。

Multiple Spatio-temporal Analysis of Summer Half Year Precipitation in Southwest China

Based on summer half year monthly rainfall data of Southwest China from China Meteorological Data Center,the REOF(rotated empirical orthogonal function) method is used to divide Southwest China into four regions: Chuanxibei region,Chuanyu region,Yunchuan region and Guizhou region,the precipitation characteristics in these four regions are analyzed by the multinomial tendency and standard Morlet wavelet transformation.The result shows that the precipitation tendencies are different in each region,Chuanxibei region does not show remarkable tendency,Chuanyu region presents upward tendency,while Yunchuan and Guizhou show downward tendency at first and then upward.The precipitation periodicities of Southwest China are different in each region too.There is evident short periodicity in every region.But distinct differences are shown when it comes to the long periodicity,not only on the significance of long temporal periodicity but also on the other aspects such as the configuration of wet and dry periods in different regions.