About rainfall variability maps

How were the maps created?

Rainfall data are recorded at a network of weather 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 rainfall variability maps were based on daily rainfall data from about 18000 weather stations. This 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, an objective analysis technique was then applied to these station values to produce regular gridded datasets (3-monthly and annual) covering Australia. Based on these grids, 10th, 50th and 90th percentile values were calculated for each gridpoint. The variability index value (3-monthly and annual) was calculated from the percentile values.

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 about 18000 weather stations across Australia were used to create the rainfall variability maps. These stations are shown in the map below.

recording stations used in the annual and 3-monthly rainfall variability analysis

Rainfall metadata

The following metadata summary, and detailed metadata file, provide information about the 3-monthly and annual gridded rainfall variability datasets. For example, information is provided about the format, spatial extents and analysis techniques used to generate the grids.

TITLE: Three-monthly and annual rainfall variability gridded datasets.
DESCRIPTION: Three-monthly and annual rainfall variability grids. The grids show rainfall variability indices across Australia in the form of a two-dimensional array. The indices are based on the period 1900 to 2019.
CUSTODIAN: Bureau of Meteorology
AVAILABLE FORMAT TYPE(S): ASCII row major, NetCDF, Shapefiles (upon request)
SCALE/RESOLUTION 0.05°/5 km; 0.01°/1 km (upon request)