老哈河流域水文要素变化研究

对老哈河流域近50a的水文要素进行了年际变化、年代际变化和线性变化趋势的研究,结果表明:(a)年降雨量的年际变化幅度最均匀、离散度最小,而年径流深和年径流系数的年际变化不均匀、离散度大.降雨量是影响径流的主要因素,但并不是唯一因素,在某些年份径流还受到其他因素的强烈干扰.另外,年径流深不仅受年降雨总量的影响,也受降雨的年内时空分布的影响.(b)从20世纪60年代到21世纪初,各要素的年代际变化不一致:年降雨量变化为少-多-少-多-少,年径流深和年径流系数变化为多-少-少-多-少.年降雨量年代际距平变化最小,变化幅度较平缓,而年径流深和年径流系数的年代际变化都比年降雨量的年代际变化大得多.(c)降雨量没有明显的增减变化,而径流却具有显著的减少趋势,其中年径流深通过了95%的置信度检验,年径流系数通过了99%的置信度检验.分析结果表明,径流的变化除了受降雨量的影响之外,还可能受气温变化和人类活动等其他因素的影响.

Variations of hydrological elements in Laohahe River Basin

The annual variation, decadal variation and linear variation trend of the hydrological elements in the Laohahe River Basin over the last 50 years were studied. The results show the following: (a) The variation of the annual precipitation is the most uniform and its discrete degree is the smallest, while the variations of the annual runoff depth and coefficient are not uniform and their discrete degrees are large. The precipitation is the main factor but not the only factor affecting the runoff. In some years, the runoff is strongly influenced by other factors. The runoff depth is also influenced by the total amount of the annual precipitation and its annual spatio-temporal distribution. (b) From the 1960s to the early 2000s, the decadal variations of various hydrological elements have been different: the variation of the annual precipitation is small-large-small-large-small, and the variations of the annual runoff depth and annual runoff coefficient are large-small-small-large-small. The decadal variation of the annual precipitation is the smallest and the variation amplitude is also small, while the decadal variations of the annual runoff depth and the annual runoff coefficient are much larger, (c) The precipitation amount has no obvious variation, but the runoff shows a significant decrease. The annual runoff depth is verified at a confidence level of 95%, and the runoff coefficient is verified at a confidence level of 99% . The analytic results indicate that the variation of runoff in the Laohahe River Basin is mainly influenced by precipitation and also by other factors, such as variations of air temperature and human activities.