Simulation of evapotranspiration from Florida pine flatwoods

An evapotranspiration model (ETM), including three submodels of transpirati on, rainfall interception and substrate (soil or water surface) evaporation , was developed for the simulation of evapotranspiration (ET) from cypress (Taxodium ascendens) wetlands and slash pine (Pinus elliottii) uplands in F lorida flatwoods. Transpiration was scaled up from the leaf level to the ec osystem level by incorporating information on ecosystem structure (e.g. spe cies composition, tree density, leaf area index), turbulence transport in a nd from the canopy, stomatal conductance and meteorological information. Th e rainfall interception submodel was physically derived from the intercepti on processes. The substrate evaporation submodels for the open surfaces in the wetlands and forest floors in the pine uplands were developed based on field observations. The model was tested with an independent data set acqui red by eddy correlation. Daily and seasonal patterns of ET, bulk aerodynami c conductance, bulk stomatal conductance and canopy dryness index of these two ecosystems were simulated and the sensitivity of ET to environmental co nditions was evaluated. (C) 1998 Elsevier Science B.V. All rights reserved.