About decadal and multi-decadal rainfall maps

How were the maps created?

Decadal and multi-decadal rainfall data is recorded at a network of stations across Australia. The data from these weather stations are stored electronically in the Bureau of Meteorology's database called ADAM (Australian Data Archive for Meteorology).

The 10, 20 and 30-year average rainfall maps are based on daily rainfall data from between 4000 and 7000 weather stations. The daily data were extracted from ADAM and a number of quality control checks were then applied to the data. For example, the data were checked for missing values over the length of the data record.

After the quality checks were applied to the data, monthly totals were calculated for each of the weather stations. An objective analysis technique was then applied to these station averages to produce regular gridded datasets covering Australia. These gridded datasets were analysed to obtain annual averages over each specified period.

Finally, the gridded data were visualised in a geographic information system and the colour maps created through this process.

Stations used in the analysis

Daily rainfall data from between 4000 and 7000 weather stations across Australia were used to create the decadal & multi-decadal rainfall maps. These stations are shown in the maps below.

Rainfall metadata

The following metadata summary, and detailed metadata file, provide information on the decadal and multi-decadal rainfall grids. For example, information is provided about the format, spatial extents and analysis techniques used to generate the grids.

TITLE: Decadal and multi-decadal mean annual rainfall data.
DESCRIPTION: Decadal and multi-decadal mean annual rainfall grids. The grids show the rainfall values across Australia in the form of a two dimensional array. The data extend from 1900 onwards.
CUSTODIAN: Bureau of Meteorology
GEOGRAPHIC EXTENT NAMES(s): Australia
AVAILABLE FORMAT TYPE(S): ASCII row major, NetCDF, Shapefiles (upon request).
SCALE/RESOLUTION 0.05°/5 km; 0.01°/1 km (upon request)