岷江径流变化特征及其对青藏高原气候变化的响应

LONG-TERM TREND OF RUNOFF IN MINJIANG BASIN AND ITS RESPONES TO CLIMATE CHANGE OVER TIBETAN PLATEAU

依据1961～2003年水文气象资料,运用Mann-Kendall检验和线性倾向估计方法进行了岷江年径流、青藏高原年气温与年降水长期变化特征分析及其变化趋势显著性检验,利用Pearson相关分析研究了岷江径流变化与青藏高原气温和降水间的相关性。结果表明:(1)在青藏高原年平均气温显著升高而年降水略有增加但不显著的气候环境下,岷江径流量总体呈减少的变化趋势,年变化率分别为上游紫坪铺站-2.619 0m3/s、下游高场站-6.538 5m3/s,其中紫坪铺站径流减少趋势十分显著,通过了5%显著水平的信度检验;从季节变化上看,岷江径流减少主要发生在夏季和秋季,而以春季变化最少;从时间变化特性看,在60～80年代,岷江年径流呈现出年代际的周期性波动变化。(2)岷江径流随青藏高原平均气温的升高而减小;青藏高原降水与岷江径流间的相关性在上下游及季节上则表现不同,与春季径流的相关性最强,与上游紫坪铺站径流具有弱负相关性,而与下游高场站径流具有显著的正相关性;同时,岷江径流变化对青藏高原气温和降水变化在时间响应上还表现出季节上的滞后性。

On the basis of climate and hydrology database from 1961to 2003,the Mann-Kendall test and linear trend method were used to detect the long-term trend of runoff in Zipingpu and Gaochang hydrological station in Minjiang Basin,and the temperature and precipitation over Tibetan Plateau.The response of characteristic of runoff in Minjiang Basin to temperature and precipitation over Tibetan Plateau was researched by using Pearson correlation analysis method.The result shows that：（1）As a whole,there was a decreasing trend in runoff in Zipingpu and Gaochang hydrological station in Minjiang Basin when there was an obvious increasing trend in temperature,while there was a weakly increasing trend in precipitation over Tibetan Plateau during the past 43years.The annual runoff in Zipingpu hydrological station showed a significant and continuous decrease with the 5%level of significance and the decreasing rate was-2.619 0 m^3/s/year.The slope was-6.538 5m^3/s/year in Gaochang hydrological station.The runoff in the 1960s and the late 1980swas increasing,but decreasing in the early 1970sand period from 1990to 2003.As for seasonal variation,the runoff reduction primarily took place in summer and autumn,but very small in spring.（2）As the temperature over Tibetan Plateau increased,the runoff in Zipingpu and Gaochang hydrological station in Minjiang Basin decreased.The correlation between precipitation over Tibetan Plateau and runoff in Minjiang Basin varied with different section of Minjiang River and different season,for example,there were significant correlation between precipitation over Tibetan Plateau and runoff in spring in Minjiang Basin,there was a weakly negatively correlated between precipitation over Tibetan Plateau and runoff in Zipingpu hydrological station in Minjiang Basin,and the precipitation over Tibetan Plateau have strong positive correlation with runoff in Gaochang hydrological station in Minjiang Basin.Besides,there was a time lag for the effect of climate change over Tibetan Plateau on runoff in Minjiang Basin.