长江大通水文站流量减少及其原因分析

Abstract

气候变暖不仅引起气候要素变化，也引起径流变化。这些变化还引起环境和社会经济变化，因此，研究气候变化对水文要素的影响对未来水资源规划和管理有重要意义。位于长江最下游的大通水文站，是中国东海的海洋潮汐所能到达的河流的上界，是控制长江流域入海径流的重要水文站。本文运用一元、多元回归分析和M-K方法，对近几十年来长江大通站流量减小现象和原因进行了分析。结果表明，在1951~2011年期间，大通站无论是年平均流量，还是丰、枯水期流量都有明显的减少现象，特别是在1994年以后，气候变暖显著，年流量和丰、枯水期流量减小趋势更加显著。流量减小的原因与气温显著升高、降水量和相对湿度显著减少有很大关系，降水量对流量减小可贡献61.9%，相对湿度可贡献18.6%，气温可贡献13.5%，日照时数可贡献6.0%。在丰、枯水期，气象要素的贡献略有差异。The increase in temperature not only causes changes in many other climate elements but also al-ters the timing and magnitude of runoff. Such changes raise the possibility of environmental and socioeconomic dislocations, and they have important implications for future water resources planning and management. Datong hydrological station, located at downstream of the Yangtze River, is an important station controlling the Yangtze River basin and is the uppermost boundary of ocean tide rising of East China Sea. Its hydrological elements change obviously because of climate warming. In the present paper, simple and multiple regression analysis and M-K method were used to research the variations and trends of flow and meteorological elements of Datong hydrological station. The results showed that there were obvious intra- and inter-annual variations for the annual mean flow during the year of 1951-2011 in Datong station. The annual mean and high water period flow decreased significantly and low water period flow increased slightly. When air temperature rose significantly after 1994, precipitation, wind speed, relative humidity and sunshine duration decreased, and annual mean flow, low and high water period flow also decreased. There was closed relationship between flow and meteorological elements, in which the contributions of precipitation, temperature, relative humidity and sunshine duration to decrease of annual mean flow were about 61.9%, 18.6%, 13.5%, and 6.0%, respectively. There were different contributions of meteorological elements to decrease of high and low water periods flow.