Daily total precipitation: ANUClimate 1.0, 0.01 degree, Australian Coverage, 1970-2014

Abstract

Daily total precipitation for Australian continent between 1970-2014. Daily rainfall totals are useful for estimation of soil moisture for plant growth and surface runoff via soil water balance modelling. Modelled by expressing each daily value, including zero rainfall, as a normalised anomaly with respect to the gridded 1976-2005 mean for each month, as provided by ANUClimate_v1-0_rain_monthly-mean_0-01deg_1976-2005. The daily anomalies were interpolated by trivariate thin plate smoothing spline functions of longitude, latitude and vertically exaggerated elevation using ANUSPLIN Version 4.5. Station elevations were 0.05 degree local averages of grid values from the GEODATA 9 second DEM version 3 as provided by ANUClimate_v1-0_dem05_terrain_0-01deg. There was an average of 6384 Bureau of Meteorology data points per day between 1970 and 2014. The mean absolute value of all individual cross validation residuals provided by the spline analysis is 0.95 mm (50% of the overall mean). Extreme studentised residuals clearly identified data errors associated with unrecognised missing values, unrecognised accumulated values, and values recorded on the wrong (usually preceding) day. There were on average around 5 such extreme residuals per day. The rainfall occurrence of the individual cross validated days agrees with the rainfall occurrence of 91% of all days of record, where daily rainfall occurrence is defined as daily rainfall exceeding 0.2 mm. A comprehensive assessment of the analysis and the factors contributing to the quality of the final interpolated monthly rainfall grids is in preparation.