甘肃省长江流域蒸发量时空变化特征及趋势研究

Spatial-temporal variation characteristics and trend of evaporation in the Yangtze River basin in Gansu Province

近几年,区域气候发生了较大变化,为深入研究甘肃省长江流域气候变化特征,本文选择流域内20cm口径蒸发皿监测资料,采用累积距平法、Mann-Kendall检验法、Lee-Heghinian法等三种方法对流域蒸发皿蒸发量时空变化特征及演变趋势展开了研究。结果表明,蒸发主要集中在4—8月,其中5—8月最为集中,占全年的51.9%,7月蒸发量最大;流域平均蒸发量整体呈逐年减小趋势,蒸发量共减小315.6mm,平均减小速率为5.1mm/年;蒸发主要集中在夏季。白龙江片的逐年平均蒸发量整体大于嘉陵江片的蒸发量,蒸发量均出现整体减小的趋势;蒸发量从舟曲、宕昌等海拔较高的区域逐渐向海拔较低的区域减小;流域蒸发量在1974年出现变异且流域蒸发量出现显著性减小趋势。本研究成果可以为流域生态环境治理、水电开发、气候变化研究提供数据参考。

In recent years,there have been significant changes in the regional climate.In order to delve deeper into the climate change characteristics in the Yangtze River basin in Gansu Province,this paper selected the monitoring data from 20cm diameter evaporation pans in the basin.Three different methods,namely the cumulative departure method,Mann-Kendall test,and Lee-Heghinian method,were employed to investigate the spatial-temporal variation characteristics and evolution trend of evaporation in the basin.The results show that the evaporation is primarily concentrated from April to August,with the period from May to August being the peak,accounting for 51.9%of the annual total,and July exhibiting the highest evaporation levels.Overall,there is a decreasing trend in the average basin evaporation,with a total decrease of 315.6mm and an average reduction rate of 5.1mm per year.Evaporation is predominantly concentrated during the summer season.The average annual evaporation in Bailong River region is higher than that in Jialing River region,with both regions experiencing an overall decrease in evaporation.Evaporation decreases gradually from regions with higher altitudes,such as Zhouqu and Dangchang,to lower-altitude areas.Notably,there was a variation in basin evaporation in 1974,and a significant decreasing trend in basin evaporation has been observed.The findings of this study can serve as valuable data references for ecosystem management,hydropower development,and climate change research in the basin.