29.1 Evaporation from landscape
Evapotranspiration from the landscape was estimated based on the AWRA-L version 1.0.0 (Van Dijk 2010) model outputs.
Using climate grid data for the Adelaide region (including precipitation, temperature and solar radiation data), AWRA-L was used to estimate the evapotranspiration depth at each grid point within the region. Only evapotranspiration from the landscape is considered; therefore, the surface areas of the major storages and the off-channel water storages (local catchment reservoirs) were excluded from the analysis.
The average evapotranspiration depth across the Adelaide landscape was determined as the weighted mean of evapotranspiration occurring from the relevant grid points within the region boundary. Points were weighted on the area they represented within the Adelaide landscape to remove edge effects (where the area represented is not wholly within the reporting region) and the effect of changing area with changing latitude. The depth of evapotranspiration was converted to a volumetric estimate by multiplying by the total area of the landscape in the Adelaide region.
Assumptions, Limitations, Caveats and Approximations
- The gridded climate input data were subject to approximations associated with interpolating observation point data to a national grid detailed in Jones et al. (2007).
- The evapotranspiration estimates were subject to the assumptions of the AWRA-L model detailed in Van Dijk (2010).