汶上县近50年蒸发量及有效降水的变化特征

Variation Characteristics of Evaporation and Effective Precipitation in Wenshang County in Recent 50 years

根据汶上县1961—2010年蒸发皿蒸发量和降水量的气象观测资料,详细分析了汶上县近50年蒸发皿蒸发量和降水量的年际、季节变化特征。结果表明:(1)近50年来,蒸发皿蒸发量整体呈现不断下降的趋势,减少速率为-10.8 mm/10年;(2)蒸发皿蒸发量的季节变化特征明显,表现为春季和夏季蒸发量偏多,分别占全年蒸发量的31.6%和37.7%,而秋季和冬季的蒸发量相对偏少;(3)降水量总体呈现曲线波动状态,变化速率为-0.04 mm/10年,整体变化不明显;(4)夏季降水量在全年降水量中所占比重最大。

Based on the meteorological observation data of pan evaporation and precipitation in Wenshang County from 1961 to 2010, the interannual and seasonal variation characteristics of pan evaporation and precipitation in Wenshang County in recent 50 years were analyzed in detail. The results showed that:(1) over the past 50 years,the overall evaporation capacity of the pan had shown a downward trend, with a reduction rate of-10.8 mm/10 a;(2) The seasonal variation of pan evaporation was obvious, which showed that the evaporation in spring and summer was more, accounting for 31.6% and 37.7%of the annual evaporation respectively, while the evaporation in autumn and winter was relatively less;(3) The precipitation generally presented a curve fluctuation state, the change rate was-0.04 mm/10 a and the overall change is not obvious;(4) Summer precipitation accounts for the largest proportion of annual precipitation.