Testing of vegetation parameter aggregation rules applicable to the biosphere-atmosphere transfer scheme (BATS) and the FIFE site

A realistic model of surface-atmosphere exchanges was created by coupling the Biosphere-Atmosphere Transfer Scheme (BATS) with an advanced, two-dimensional model of the atmospheric boundary layer. This was initiated and tested using data obtained from the First International Satellite Land Surface Climatology Project Field Experiment (FIFE). This model was used to investigate the acceptability of simple rules for defining the aggregate value of the parameters required to specify surface interactions, as applied to heterogeneous mixes of vegetation types allowed in BATS but appropriate to the FIFE site, namely short and long grass, mixed crops, and irrigated crops. Under the range of meteorological and surface conditions relevant to FIFE and as used in this study, these rules are shown to estimate aggregate parameters which give surface fluxes similar to those calculated with an explicit representation of separate vegetation patches, except in the particular case of artificially wetted (irrigated) patches set in an otherwise dry landscape.