28.1 Precipitation on landscape
Monthly precipitation data were produced by the Bureau of Meteorology. This was based on daily data from approximately 6,500 rain gauge stations and interpolated to a 0.05 degree (approximately 5 km) national grid (Jones et al. 2007).
The average precipitation depth across the Adelaide landscape was determined as the weighted mean of precipitation depths occurring onto 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 precipitation was converted to a volumetric estimate by multiplying by the total area of the landscape within the Adelaide region.
Only precipitation falling onto the landscape is considered here. Precipitation falling onto surface water and off-channel water storages (farm dams) was not included.
Assumptions, Limitations, Caveats and Approximations
The precipitation estimates were subject to approximations associated with interpolating observation point data to a national grid detailed in Jones et al. (2007).