长江上游气温时空变化特征分析

Analysis of Spatial and Temporal Variation of Air Temperature in the Upper Reaches of the Yangtze River

摘要: 为了获得长江上游地区在全球变暖背景下的气温时空变化特征，本文利用中国气象局国家气候中心提供的长江上游近60年的逐日平均气温资料，通过趋势分析、Morlet小波变换以及M-K突变分析方法，对长江上游气温的时空变化特征进行了分析。结果表明：1) 从空间分布上看，长江上游多年平均气温自西北向东南逐渐升高；而在变化趋势上，长江上游平均气温升温趋势自西北向东南减弱，其中长江源区和金沙江水系区域升温幅度最大。2) 长江上游地区1961~2020年的多年平均气温为12.1℃，近60年平均气温上升趋势显著，增温率为0.194℃/10a，并且21世纪00年代增幅最大，同时，四季中以冬季增温最为明显。3) 长江上游地区平均气温突变发生在2001年，春、夏、秋、冬四季平均气温突变时间分别为2003、2005、1998和1997年前后。在周期变化方面，近60年来长江上游地区夏季和冬季的平均气温在3 a、6~7 a和10~15 a的时间尺度上都存在周期变化。

Abstract: In order to obtain the upper Yangtze River region in spatial and temporal variation characteristics under the background of global warming temperatures, using the daily average temperature data in the upper reaches of the Yangtze River in recent 60 years provided by the National Climate Center of China Meteorological Administration, this paper analyzes the temporal and spatial variation characteristics of temperature in the upper reaches of the Yangtze River through trend analysis, Morlet wavelet transform and M-K catastrophe analysis. The results show that: 1) In terms of spatial distribution, the annual mean temperature in the upper reaches of the Yangtze River increased gradually from northwest to southeast; on the other hand, the warming trend of average air temperature in the upper reaches of the Yangtze River weakened from northwest to southeast, with the largest warming in the source region of the Yangtze River and the Jinsha River system. 2) The annual average temperature in the upper reaches of the Yangtze River was 12.1˚C from 1961 to 2020, and the average temperature increased significantly in the last 60 years, with a warming rate of 0.194˚C/10a. The increase rate was the largest in the 2000s, and winter was the most obvious temperature increase in the four seasons. 3) The abrupt change of mean temperature in the upper reaches of the Yangtze River occurred in 2001, and the abrupt change time of spring, summer, au-tumn and winter were around 2003, 2005, 1998 and 1997, respectively. In terms of periodic variation, the average temperature in summer and winter in the upper reaches of the Yangtze River has a periodic variation on the time scales of 3 a, 6~7 a and 10~15 a in the last 60 years.