基于称重法对影响蒸发蒸腾量的主要气象因子研究分析

Study of main meteorological factors affecting evapotranspiration based on gravimetric method

通过模拟实验采用称重法测定了不同时间尺度下的蒸发皿水面蒸发量与充分灌水条件下植物蒸腾耗水量,同时监测对应时段影响蒸发蒸腾量变化的的气象因子。通过Pearson相关分析法与偏相关检验对蒸发蒸腾量与气象因子间的相关性进行了分析,同时在此基础上,对相关性较高(在α=0.01水平上极显著相关且通过偏相关筛选)的几个主要气象因子与水面蒸发量、植物潜在蒸发蒸腾量变化过程间的相关关系进行了多元非线性拟合,构建了简单的潜在蒸发蒸腾量计算方程,并进行了检验。结果显示:(1)影响水面蒸发与植物蒸腾的主要气象因子一致:温度、太阳净辐射与相对湿度;(2)太阳净辐射与温度、湿度的变化有较高的相关性(r=0.718,r=-0.639);(3)利用温度和湿度两项指标可以较好地模拟蒸发量与蒸腾量的变化过程(R^2=0.743),对于缺乏太阳净辐射资料的小灌区(点),可以利用温、湿度和作物参数构建近似的作物蒸发耗水模型,基于实时的气象资料计算对应时段作物的蒸腾蒸发耗水量,以便快速获得作物的耗水量与需水量,实时掌握农田水分亏缺状况,进行及时补灌。

In order to construct a simple calculation model for transpiration and evaporation of farmland,obtain the water consumption and the water demand of crops quickly,and to obtain the status of water deficit in a timely manner,this study used a gravimetric method to measure the evaporation of water from an evaporation pan at different time scales,and measure the transpiration water consumption of plants under the condition of sufficient irrigation,while the meteorological factors that affect transpiration in the corresponding period were monitored.The correlation between evapotranspiration and meteorological factors was analyzed by Pearson correlation analysis method and partial correlation test.The correlations of volume change and several major meteorological factors with high correlation with surface water evaporation and potential plant evapotranspiration were analyzed with multivariate non-linear fitting.Thus,a simple calculation equation of potential evapotranspiration was constructed and tested.The results showed that(1)the main meteorological factors that affect water surface evaporation and plant transpiration were temperature,net solar radiation,and relative humidity;(2)net solar radiation had a high correlation with changes in temperature and humidity(r=0.718,r=-0.639);(3)the evaporation and transpiration were well simulated by using temperature and humidity(R^2=0.743).For small irrigation areas(points)that lacked solar net radiation data,an approximate crop evaporation water consumption model was constructed using temperature,humidity,and crop parameters.Based on real-time temperature and humidity data,it is possible to calculate the crop’s evapotranspiration water consumption for the corresponding period to quickly obtain the crop’s water consumption and their water demand,so this could help to obtain the real-time farmland water deficit status and provide timely supplemental irrigation.