基于交叉小波的多尺度气候变化及其对径流的影响

The Multi-Timescale Climate Change and Its Impact on Runoff Based on Cross-Wavelet Transformation

摘要: 选取石羊河流域代表性的气象站和水文站资料，利用趋势分析、相关分析及交叉小波分析等多种方法探讨不同时间尺度上气候变化特征及其对地表径流的影响。结果显示：上游降水量在20世纪后半叶显著减少，而中、下游降水量在20世纪90年代中期以后呈显著下降趋势。整个流域温度、最高温度均呈极显著的增加趋势。上游降水量与地表径流在2~5 a尺度上(1960s、1980~2005年)正相位关联性强，上游温度与地表径流在6~8 a时间尺度上(1970s)负相位关联性强，且上游降水与地表径流的高凝聚性正相关更显著，降水对上游径流的形成起主导作用。下游年际气候要素与年径流在各时间尺度上基本无显著关联性，但下游夏季最高温度与夏季径流在20世纪后期呈现2~4 a的显著共振周期，人类活动与气候要素共同影响着下游夏季径流的短周期振荡。

Abstract: Based on meteorological and hydrological data in Shiyang River, climatic change characteristics and its impact on runoff in different time scales were discussed based on Mann-Kendall test, correlation analysis, wavelet analysis and cross-wavelet test methods. The results show that precipitation in the upper reaches decreases significantly during the period from 1956 to 2001, precipitation in the lower reaches decreases after mid-1990s, and temperature and maximum temperature increases significantly (p < 0.01) in the entire Shiyang River. There is a good correspondence between frequency domains of annual and summer precipitation and annual runoff in the upper reaches at the scales of 2 - 5 years (1960s, 1980- 2005), and there is a significant negative correlation between annual and summer temperature series and runoff at longer-time scales (6 - 8 years, 1970s). The precipitation change plays a major role in runoff change. There are no significant correlations between annual precipitation and temperature series and annual runoff at multi-time scales in the lower reaches, and annual runoff change in the lower reaches is influenced by human activity. However, summer temperature and summer runoff in the lower reaches are significant negative correlated with at the scales of 2 - 4 years during the period from 1978 to 1995, summer runoff change in the lower reaches is affected by the combined impact of human activity and climate change.