Evapotranspiration Components Structure

Abstract

The term evapotranspiration structure denotes separation into two basic components: transpiration (water movement through and from plants) and evaporation (from other surfaces). An approximative method of evapotranspiration structure calculation is presented. It is based on the empirically estimated relationship between the canopy leaf area index (LAI) and relative potential transpiration, i.e., on the ratio of potential transpiration and potential evapotranspiration. It was found that this relationship can be used universally for a wide variety of crops. Typical daily and seasonal courses of the evapotranspiration structure elements of crops are demonstrated, i.e., increasing transpiration rate with LAI and, conversely, decreasing evaporation rate with LAI increase. The proposed method of potential evapotranspiration structure calculation is involved in the proposed method of evapotranspiration calculation.