Evapotranspiration in the Everglades; Comparison of Bowen Ratio Measurements and Model Estimations

The Everglades in south Florida is a marsh system where most of the time wet vegetated marshes and open water features prevail. Rainfall and evapotranspiration (ET) are the main parameters in the hydrology of the Everglades. The delicate balance between rainfall and evapotranspiration maintains the hydrology system in either a wet condition or dry condition. Based on a literature review of both measurement and estimate of evapotranspiration in south Florida, 134.5 cm is an average estimate of annual potential evapotranspiration or evapotranspiration from wetlands and open water in south Florida. In this study, comparisons are made between Bowen ratio-energy balance measured ET at nine sites in the Everglades and wetland ET estimations with a Simple Model (also cited as Abtew Equation or Simple Abtew equation) that is based on solar radiation. The results of this study cross-validate model estimates and Bowen ratio measurements of ET in marshes because the Simple Model was calibrated independently from a previous lysimeter ET study. The area is warm, humid, wet, high solar radiation and low wind speed with prevalent wind direction of north-north-east, east-north-east and east-southeast.