近50年来额济纳三角洲气象要素变化对蒸发皿蒸发量的影响

Effects of Climatic Variables on Pan Evaporation in Ejina Delta in the Recent 50 years

识别蒸发皿蒸发量与气象要素的关系是认识气候变化对水循环影响的重要基础。根据额济纳旗气象站1961年-2001年的常规气象数据,建立了额济纳三角洲地区蒸发皿蒸发量与相关气象要素关系的Penpan模型,并据此估算了2002年-2011年的蒸发皿蒸发量,延展了蒸发皿蒸发量的时间序列,进而分析了1961年-2011年研究区蒸发皿蒸发量和相关气象要素的变化趋势及其相互关系。研究结果表明:(1)1961年-2011年期间,额济纳三角洲蒸发皿蒸发量呈下降趋势(气候倾向率为年-215.5mm/10a),而平均气温呈上升趋势,风速、总辐射、相对湿度则均呈下降趋势;(2)总体上,蒸发皿蒸发量对各气象因子的敏感程度从大到小依次为风速、相对湿度、太阳总辐射、平均气温;1961年-2011年,蒸发皿蒸发量对风速、相对湿度的敏感性呈下降趋势,对太阳总辐射、平均气温的敏感性呈上升趋势;(3)风速变化对蒸发皿蒸发量变化的贡献度最大,其次是相对湿度、平均气温、总辐射。

The relationship between the pan evaporation and climatic factors is the important basis to characterize of the effects of climate change on hydrological cycle. Based on the measured meteorological data in the Ejina meteorological station from 1961 to 2001, a Penpan model was developed to reflect the relationship between the pan evaporation and four climatic variables in the Ejina Delta and to estimate the pan evaporation from 2002 to 2011. Therefore, the variations of four related climatic variables and their effects on the pan evaporation were analyzed during the period from 1961 to 2011 in the Ejina Delta. The results showed that： （1）pan evaporation presented a significant decreasing trend with a rate of-215. 5 mm·10 a-1 ,while mean tempera- ture presented an increasing trend. In addition, wind speed, total radiation, and relative humidity presented decreasing trends; （2） Generally, pan evaporation was most sensitive to wind speed, followed by relative humidity, total radiation, and mean tempera- ture. The sensitivities of pan evaporation to wind speed and relative humidity decreased while the sensitivities to total radiation and mean temperature increased during the period from 1961 to 2011;and （3）the variation of wind speed had the most contribu- tion to the variation of pan evaporation,followed by relative humidity,mean temperature,and total radiation.