中蒙干旱半干旱区冬、夏季地面气温时空变化特征分析(Ⅰ):1月

Temporal and Spatial Feature Analyses of Winter and Summer Surface Air Temperature in CMASA,Part(Ⅰ): January

为了整体地分析中蒙干旱半干旱区冬季气温的时空变化特征,首先利用1961-1997年1月的实测气温资料,分析了平均场和标准差场,然后再选取区内104个分布相对均匀的站点,对1月气温作了经验正交函数(EOF)和旋转经验正交函数(REOF)分析.结果表明:纬度、地形及西伯利亚高压是影响冬季气温的3个主要因子;区内绝大部分地区冬季气温的年际变化>2℃以上.根据EOF分析,区内冬季气温异常有'全区一致型'、 '东西差异型'和'南北差异型'三种模态;根据REOF分析,区内的冬季气温可划分为高原东北侧、南疆、北疆、青海高原、蒙古中东部及西部6个分区.区内冬季增暖明显,增暖中心在中蒙南边界的临河-富蕴及拐子湖一带,近20年平均增温达2.5℃以上,1977年是由冷转暖的突变年;区内大部分地区冬季气温变化有3～4年周期,部分地区还有8年的变化周期.

To analyse the temporal and spatial change features of the winter surface air temperature over China- Mongolia Arid- and Semiarid- Areas （CMASA） as a whole, the EOF and REOF analyses have been conducted utilizing the observed air temperature data from the selected even-distributed 104 stations in the area in January of 1961-1997, and their multi-year mean temperature field and standard variance one have been analysed as well. The main results are as follows： （1） Latitude, topography and Siberia cold high are three main factors affecting the winter temperature distribution in CMASA. （2） The standard variances of winter temperature in most of the area are larger than 2℃. （3） There are three temperature anomaly distribution modes： With the same anomaly in whole area, with opposite anomalies in the south and north or in the east and west according to the EOF analyses. （4） According to the REOF analyses of six subregions of the area, like one on the northeast side of the Plateau, South Xinjiang one, Qinghai Plateau one, North Xinjiang one, Mid- and East- Mongolia one and West-Mongolia one, were divided. （5） The winter temperature has been warmed considerably by more than 2℃ since 1961, particularly near the south border and after 1977. （6） There existed 4 or 8 year periodic changes for the winter temperature in CMASA.