沧州市近 40 年蒸发量变化特征分析简

利用沧州市气象站1971～2010年期间小型蒸发皿（口径20cm）蒸发量资料，对近40年沧州市蒸发量变化进行统计分析。结果表明，近40年沧州蒸发量变化较大，在年内呈波状分布，蒸发量最大的为6月，最小的为1月；近加年小型蒸发皿蒸发量呈总体下降趋势，蒸发量最大为2273．3min，出现在1972年，最小为1681．4mm，出现在1990年，年最大蒸发量与最小蒸发量相差591．9mm；近40年一年四季中夏季蒸发量最大，变化幅度也最大，春季次之，冬季蒸发量及变化幅度最小；不同季节蒸发量变化趋势不同，蒸发量下降主要在春季和秋季，夏季无明显变化，而冬季蒸发量呈上升趋势；沧州近40年蒸发量年代际变化呈波状变化，整体下降趋势；年代特征明显，20世纪80年代为各年代最高值，平均蒸发量为1958．6mm，高出近40年平均值39．7mm，21世纪以来蒸发量为1880．9mm，为各年代最低值，比平均值低38．0mm。

Analysis of Evaporation Change Characteristics of Cangzhou in Recent 40 Years

The observation data of 20 cm caliber evaporation pan from weather stations of Cangzhou were analyzed, time ranging form 1971 to 2010. The results showed that evaporation changes greatly in Cangzhou in recent 40 years, which shows a wavy distribution. The maximum e- vaporation value is in June, while minimum evaporation value is in January. The evaporation have a decrease trend in the past 40 years. The maximum evaporation is 2 273.3 mm, appeared in 1972, and the minimum evaporation is 1681.4 mm, appeared in 1990. The difference be- tween the two is 591.9 mm. It dropped quickly and changed greatly in summer, and next in spring, smallest in winter. Different season have different variation trends. Evaporation decrease mainly appears in spring and autumn, while an increase trend appears in winter. There＇ s no obvious change in summer. It is proved that the change of time distribution is obvious. The highest evaporation value is 1 958.6 mm, appears in the 1980s, which is 39.7mm higher than the average value. The minimum value is 1 880.9 mm, appears in the 2010s, which is 38.0 mm lower than the average value.