黑河上游水文气象变量变化趋势多尺度分析

MULTI-SCALE ANALYSIS OF THE LONG-TERM TREND OF THE HYDROMETEOROLOGICAL VARIABLES IN THE UPPER REACH OF THE HEIHE RIVER,NORTHWEST CHINA

选取黑河上游祁连、肃南、托勒和野牛沟4气象站(1959—2009年)和莺落峡及札马什克两水文站(1978—2007年)数据,应用Mann-Kendall非参数趋势检验法对月、季和年3种不同时间尺度的黑河上游气温、降水及径流进行变化趋势显著性检验,并在此基础上分析了气候变化背景下气温和降水对出山径流的影响。结果表明:年尺度上,黑河上游水文气象变量均呈上升趋势。其中,祁连和托勒年平均气温显著上升;季节尺度上,黑河上游气温、降水和出山径流均呈上升趋势。秋冬季气温比春夏季气温上升更明显,降水增加主要表现在夏季。月尺度上,除肃南10月份气温呈下降趋势外,其余均表现为上升趋势。降水在1、5—10和12月表现为增加趋势,在2—4和11月呈减少趋势。莺落峡水文站径流全年呈增加趋势,而札马什克水文站在4—11月径流呈增加趋势,其余月份表现为减少趋势。黑河上游秋冬季温度升高和夏季降水增加对增加出山径流量具有重要作用。

This paper analyzed the long-term trend of the hydrometeorological variables including air tem- perature, precipitation （for the period of 1959--2009）and discharges （for the period of 1978--2007） at the monthly, seasonal and annual scales in the Upper Reach of the Heihe River Watershed, Northwest China, using the nonparametric Mann-Kendall trend test. The effects of air temperature and precipitation on the discharges were also examined in the study watershed. The results indicate that the hydrometeorological variables had all increased at the annual scale during the study period, and annual mean temperatures in the Sunan and Tuole Weather Stations significantly increased. The seasonal mean temperatures, precipitation and discharges had also shown an increased trend, with a larger rise of the mean temperatures in autumn and winter than those in spring and summer. The increase in seasonal mean precipitation mainly occurred in summer. At the monthly scale, the monthly mean temperatures had increased at all four weather sta- tions except at the Sunan Weather Station in October. The monthly mean precipitation displayed a mixed pattern during the study period, showing an increasing trend during the months of January, May through October, and December, and a decreasing trend during the other months. The monthly mean discharges showed an increasing pattern throughout the year at the Yingluoxia Gauge Station （located at the outlet of the Upper Reach of the Heihe Watershed） while the monthly discharges at the Zamashike Gauge Station （located in the upstream of the Upper Reach） exhibited increasing trend during the months of April through November. The increased mean temperatures in autumn and winter and the rising mean precipita- tion in summer contributed to the increasing mean discharges significantly.