长江源区河流水温对气候变化的响应

基于长江源区沱沱河流域1977~2015年月平均气温、河流水温同步资料,采用线性趋势分析和小波分析方法,研究了沱沱河5~10月气温与水温的年际变化趋势及周期性特征,并进一步分析了水温与同期气温的线性相关性。结果表明:近40 a来,沱沱河流域5~10月气温和水温均呈现出升温趋势,2011~2015年较1977~1980年气温分别升高0.6,1.3,1.3,1.0,1.3,2.0℃,水温分别升高0.6,1.6,1.7,1.1,1.0,0.2℃;水温上升趋势突变发生时间普遍滞后于气温,突变点分别在1997~2003年和2005~2007年之间;7~10月水温与气温变化均存在明显的28 a时间尺度的主周期,而5,6月气温与水温周期不一致;水温与气温的相关关系密切,可以认为气温变化是影响水温变化的主要原因之一。

Response of river water temperature to climate change in source regions of Yangtze River

On the basis of monthly mean air temperature and synchronized river water temperature data from 1977 to 2015 of the Tuotuo River in the source region of the Yangtze River, the variation trends and periodicity of temperature and water temperature from May to October were analyzed by linear trend method and wavelet analysis method. Furthermore, the linear correlation between temperature and water temperature were detected. The results showed that in the past 4 decades, the temperature and water temperature in the Tuotuo River Basin showed a warming trend from May to October, and the temperature in the period of 2011~2015 increased by 0.6, 1.3, 1.3, 1.0, 1.3, and 2.0℃ respectively from 1977~1980 and the water temperature increased by 0.6, 1.6, 1.7, 1.1, 1.0, and 0.2℃, respectively; The time of water temperature trend mutation always lagged behind that of temperature, and the mutation point was between 1997~2003 and 2005~2007 respectively; From July to October, there were obvious main cycles of 28-year time scales for water temperature and air temperature changes, while there were distinction of the main cycle for water and air temperature in May and June. There was a good linear correlation between average water temperature and air temperature, and it can be considered that air temperature change was one of the main causes for the change of water temperature.