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Abstract: In Australia and globally, changes in the entire distribution of daily precipitation are poorly understood. An analysis of spatiotemporal changes in the intensity and frequency of wet and all day Australian rainfall between 1958–1985 and 1986–2013 is presented using three different gridded data sets of daily precipitation based on varying underlying station data and interpolation methods. Our analysis method provides a complete picture of changes in the entire distribution as well as a coherent picture of the spatial changes across Australia. We find that the spatial pattern of changes in total rainfall is similar to the pattern of change in wet day frequency but not to change in wet day intensity. Furthermore, more grids across Australia show statistically significant increases than decreases in rainfall intensity throughout the wet day distribution. This means that when it rains (i.e., limited to the wet day distribution), whether it is light, moderate, or extreme rainfall, it rains more. [ABSTRACT FROM AUTHOR]

Daily gridded precipitation data are needed for investigating spatiotemporal variability of precipitation, including extremes; however, uncertainties related to daily precipitation products are large. Here, we compare a range of precipitation grids for Australia. These datasets include products derived solely from in situ observations (interpolated datasets) and two products that combine both remote sensed data and in situ observations. We find that all precipitation grids have similar climatologies for annual aggregated precipitation totals and annual maximum precipitation. The temporal correlations of daily precipitation values are higher between the interpolated datasets, but the correlations between the most widely used interpolated product (AWAP) and the two remotely sensed products (TRMM and GPCP) are still reasonable. Our results, however, point to distinct structural uncertainties between those datasets gridding in situ observations and those datasets deriving precipitation estimates primarily from satellite measurements. All datasets analysed agree well for low to moderate daily precipitation amounts up to about 20 mm but diverge at upper quantiles, indicating that substantial uncertainty exists in gridded precipitation extremes over Australia. [ABSTRACT FROM AUTHOR]