A METHOD FOR CALCULATING EVAPORATION CAPACITY——APPLICATION OF H.L.PENMAN'S FORMULA
Liu Huaiqi Shandong Agricultural University
Here is discribed how to calculate evaporation capacity according to H.L. Penman's formula. The formula is based on energy balance and the principles of air dynamics, including many parameters each of which has special physical definition. The amount of evapotranspiration of farm land can be calculated by multiplying the largest possible evaporation capacity of water surface with a special coefficient.Therefore this method is also based on biology and physics and it takes many different factors into account.But, the formula is not perfect and it must be calibrated with actual conditions before it is applied into use.The excellent results were gotten by applying H.L.Penman's formula in different regions of China.