渭河流域气温与蒸发量时空分布及其变化趋势分析

应用Mann-Kendall统计检验方法,根据渭河流域19个气象站点的气温和蒸发量资料,分析了渭河流域1958—1999年年平均气温和蒸发量的时空分布及其长期变化趋势.结果表明,渭河流域近40年来气温逐渐升高,空间上表现为从西北部向东南部逐渐增加的分布规律.蒸发量随时间增加而逐渐减少,在空间上呈现出明显的从北部向南部逐渐减少的分布规律,近40年来渭河流域年平均蒸发量Mann-Kendall倾斜度β等值线分布呈现出明显的从东南向西北逐渐减少的趋势.初步讨论了两者之间的关系,渭河流域近几十年气温高的地区蒸发量反而小,气温低的地区蒸发量大,其原因和机制值得人们进一步探讨和研究.

SPATIAL AND TEMPORAL CHARACTERISTICS OF THE LONG-TERM TREND FOR TEMPERATURE AND PAN EVAPORATION IN THE WEI RIVER BASIN

The Mann-Kendall statistic test method is used to analyze the spatial and temporal distribution and variations for long-term trend of temperature and pan evaporation at 19 hydrologic stations in the Wei River basin from 1958 to 1999.The results show that the temperature in the studied area over the past 40 years increases in the temporal dimension and the spatial distribution of long-term trend increases gradually from northwestern part to southeastern part.The trend of temperature steadily increases especially in northwestern part of the area.In contrast,evaporation decreases in the temporal dimension.The spatial distribution of long-term trend shows a decrease tendency from north to south.The trend of evaporation decreases gradually from northwestern part to southeastern part.In addition,the relationship between temperature and evaporation is analyzed briefly.Evaporation in the area where the tendency of temperature is great shows a small tendency,and in the area where the temperature shows a small tendency,the tendency of evaporation is great.The physical background will be further investigated in the on-going study.