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

Abstract

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 measurements and estimates of evapotranspiration in south Florida, an average estimate of annual potential evapotranspiration or evapotranspiration from wetlands and open water is 134.5 cm. 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 Method (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 South Florida as the Simple Method was calibrated independently from a previous lysimeter ET study. The area is warm, humid, wet, with high solar radiation and low wind speed. Prevalent wind directions are northnorth- east, east-north-east and east-south-east.