石羊河上游1956-2009年出山径流量特征及其对气候变化的响应

利用石羊河上游气象站1956-2009年逐日气象资料及天祝县六条河流1956-2009年年出山径流量资料,应用FAO Penman-Monteith模型、小波变换及累积距平等方法分析石羊河上游天祝县出山径流量特征及其对气候变化的响应,结果表明:1956-2009年石羊河上游天祝县出山径流量在波动中总体呈微弱减少趋势,径流量变化倾向率为-0.288×10~8m~3/10a,其中,减少速度最快的是黄羊河,年径流量变化倾向率为-0.069×10~8m~3/10a.1950s,1960s及1980s为丰水期,1970s,1990s为枯水期,进入21世纪,尤其是2002-2009年径流量有所增加;降水量波动呈微弱增加趋势,降水量变化倾向率为1.165mm/10a,径流量与降水量存在显著正相关震荡,两者变化过程具有极吻合的同步性;气温整体呈明显上升趋势,气温变化倾向率为0.298℃/10a,尤其是20世纪80年代中后期以来,增温趋势更加明显;潜在蒸发量在波动中呈增加趋势,其变化倾向率为2.206mm/10a,径流量与气温、蒸发量呈显著负相关震荡;通过小波方差检验,径流量与降水量、气温及潜在蒸发量等各气候要素均分别存在22年左右、7-8年和3年左右的的显著变化周期,而且第一主周期均为准22年,径流量对气候变化响应明显.

Characteristics of mountainous runoff and its reponses to climate change in the upper reaches of Shiyang river basin during 1956-2009

Based on daily meteorological data from two stations and themountainous runoff of six rivers from 1956 to 2009,the stream flow characteristics and hydroligical responses to climatic change in the upper reaches of Shiyang river basin were analyzed by using FAO Penman-Monteith model,wavelet transform and accumulative anomaly.The results show that,firstly,there was a weak decreasing trend for the mountainous runoff in the Tianzhu region,with the runoff trend rate being -0.288×l0~8 m~3/10a,among which the reducing rate of the Huangyang river was the most abovious,with the streamflow trend rate being -0.069×l0~8 m~3/10a.Comparatively speaking,there were plentiful water periods in the 1950s,1960s and 1980s and low water periods in the 1970s and 1990s.The runoff slightly increased in 2000s,especially for the period of 2002-2009.Secondly, precipitation showed a little inecrease with the tendency rate of 1.165 mm/10 a from 1956 to 2009.The increasing trend of temperature was obvious,especially for the period of 1990s-2000s,with the inclination rate being 0.298℃/10 a.Meanwhile,the increasing trend of potential evapotranspiration,with the tendency rate of 2.206 mm/10 a,was relatively obvious during the period of 1956-2009.Thirdly,there were a significantly positive correlation between pricipitation and mountainous runoff,whose fluctuation processes appeared to be perfactly synchronic.And negative correlations were all significant both between runoff and temperature and between runoff and potential evapotranspiration.At the same time,there were significant periods at scale of 3 a, 7-8 a and 22 a for runoff,temperature and potential evapotranspiration.Furthermore,the first main periods were all quasi 22 a.Therefore,responses of the runoff variation to regional climate anomalies were impressionable, but the responses of runoff variation to each climate element were different and annual variation of runoff depended on the comprehensive effect of climate elements.