格尔木河流域近60 a降水、蒸发及温度变化特征分析

Characteristics of precipitation,evaporation and temperature at the Golmud River Catchment in recent 60 years

以西部内陆柴达木盆地格尔木河流域近60 a气候变化特征为主题,以流域水循环理论为指导,应用趋势分析、Morlet小波函数等技术手段,采用定性判断和定量分析相结合方法,首先,对研究区大气降水、气温、蒸发多年监测资料进行系统分析,包括深入了解研究区水文、水资源开发利用状况,分析其年际、年内变化规律。结果表明:(1)近60 a研究区气候由冷干向暖湿转变,研究区气温呈波动上升趋势。自1955年至今气温累积上升0.37℃,1967年之后区域气温升高速率明显增加。自1968年开始降雨量显著增加,多年平均降雨量为38.27 mm·a-1,其中7、8月份降水量增加对全年降水量增加的贡献率最大。自1956年开始蒸发量显著下降,由1956年的3 278.2 mm·a-1下降至2014年的2 211.57 mm·a-1,平均减速为18.08 mm·a-1。(2)利用Morlet小波变换对气候变化特征进行了动态周期分析,分析得出研究区内降水、蒸发和温度都存在多时间尺度特征。其中降水存在14~16 a和32~36 a左右周期,蒸发量存在9~12 a和24~27 a时间尺度的周期,而温度存在7~8 a尺度和25~27 a两个时间尺度的周期特征。根据降水周期特征,可以推测出2016-2030年左右年降水量将经历几年降水偏多期,然后呈减少趋势,温度在未来几年内呈增多趋势,而蒸发则呈减少趋势。研究成果为该区水资源合理开发利用提供科学依据。

Based on hydrological cycle theory, this paper analyzed the intra-annual and inter-annual variation characteristics of precipitation, evaporation and temperature at Golmud River Catchment, Qinghai, China, in re- cent 60 years, by using trend analysis, Morlet wavelet function, and combining qualitative judgments and quanti- tative analysis. The results show： the climate of study area is transforming from cold-dry to warm-wet, and the temperature exhibited a wavelike rises trend. Since 1955, the temperature has risen 0.37 ~C ;since 1967, the tem- perature rising rate of study area increased significantly. Since 1968, the precipitation of Golmud River Catchment increased significantly, with the average precipitation of 38.27 mm. a^-1 ; precipitation increase in July and August contributed most to the annual precipitation increase. The evaporation of study area has decreased from 3 278.2 ram. a^-1 in 1956 to 2 211.57 mm.a^-1 in 2014,with the average decrease rate of 18.08 mm.a-1. Precipitation, temperature and evaporation all presented multi-time scale features. The precipitation had the periods of 14-16 a or 32-36 a oscillations, the evaporation had the periods of 9-12 a or 24-27 a oscillations and temperature had the periods of 7-8 a or 25-27 a oscillations. According to the characteristic of precipitation cycle,the precipitation will increase for few years from 2016 to 2030, but the evaporation will decrease in the next 10 a. The analysis results offer evidences to further study on water resources development and guides to exploit water resource rea- sonably.