近50年中国气温日较差的变化趋势分析

利用近50年的气温观测资料,对中国地区的气温日较差的空间分布和时间序列变化特征进行了分析。同时分析了与日最高气温、最低气温以及平均气温时空分布之间的关系。结果发现,近50年来气温日较差呈下降趋势,其平均减小幅度为高纬度地区大于低纬度地区;不同地区及同一地区的DTR季节变化特征也不相同,我国北方多为冬季DTR下降最大,其次是春季和秋季,夏季最小。在黄淮和长江流域,以夏季和春季DTR下降最为显著。华南地区仍以冬季下降最大。气温日较差整体呈现下降趋势,中高纬度下降比低纬度明显。在相同纬度带上,由于地理状况的不同,变化趋势有所不同。同时,气温日较差的变化有明显的区域和季节性差异,特别在西部的青藏高原和新疆地区的DTR变化与东部地区的差异明显。

Variation of Diurnal Temperature Range in China in the Past 50 Years

The spatial distribution and time series of diurnal temperature range(DTR) in China are analyzed using the daily temperature data from 1950 to 2001.The relations among the maximum and minimum temperature and the mean temperature are discussed for their possible influence on DTR.The analyzed results show that DTR was decreased in China in the last 50 years.The average decrease of DTR in the high latitude is larger than that of in low latitude.The DTR in the same region or different regions have the different features in seasonal changes.In the northern China the maximum decrease of DTR is in winter,and then spring and autumn,the minimum,is in summer.In Huang-huai and Yangtze River reaches the maximum decreases of DTR are in summer and spring.In South China the maximum of DTR is in winter.On the average,the DTR is decreasing,and this decreasing is more significant in high and middle latitude regions than in low latitude.For the regions that are in the same latitudinal zone the trends of DTR changes are different because of different geographical backgrounds.The DTR has obvious seasonal change and shows a fast decrease in winter and slow decrease in summer in most regions of China,especially in Qinghai-Xizang Plateau and Xinjiang the features of DTR change are quite different from those in the eastern China.