开封市30年降水量和土壤蒸发量特征分析

Rainfall and Soil Evaporate Characteristic Analysis of Kaifeng in 30 Years

利用开封市1980—2009年连续30年的降水量资料,分析得出开封市降水量年季变化大、季节分布极不均匀、多雨少雨期交替出现、全年主要降水集中在夏季、夏季平均降水量占全年降水的一半以上的结论,根据开封市1980—2009年各月平均气温和平均湿度,运用伊万诺夫经验公式求出各月及各季的平均土壤蒸发量.开封市月土壤蒸发量与降水量的变化趋势比较一致,但是降水量的变化趋势要滞后于土壤蒸发量的变化趋势.降水量与土壤蒸发量的正负差值明显反映出开封市旱涝灾害发生程度的强弱,认为干旱和雨涝都会给农业生产带来不利影响,对产量有很大的不利影响.

Characteristics of 30-year precipitation in Kaifeng were derived by analyzing the rainfall data from 1980 to 2009.The analysis result shows substantial changes in precipitation between seasons and the uneven distribution is accompanied by alternative dry and wet periods.The precipitation in summer is the largest during the year,which accounts for more than half of the annual precipitation.According to monthly mean temperatures and monthly mean humilities from 1980 to 2009 in Kaifeng,monthly and quarterly mean evaporation data was calculated using empirical Ivanov formula.The variation in soil evaporation is consistent with the variation trend in precipitation,however,the trend of precipitation lags behind the trend of soil evaporation.The difference（positive or negative） between precipitation and soil evaporation is clearly associated with the severeness of droughts or floods occurred in Kaifeng.Both droughts and floods have adverse impact on agricultural production in Kaifeng,which will decrease the agricultural yield.