Precipitation in the Wet Tropics of Queensland, Australia

The north-eastern coast of tropical Queensland, Australia is exceptionally wet. Within this broad coastal area the mean annual precipitation in the mountainous "Wet Tropics" region (roughly 15-19°S) is among the highest in Australia, exceeding well over 2500 mm along large sections of the coast with some high elevation locations reaching over 7000 mm. In addition to high annual precipitation totals, this region is also noted for heavy rain events. Spatial patterns of precipitation were identified in a gridded daily precipitation dataset from the Australia Water Availability Project (AWAP) using K-means cluster analysis. Synoptic and mesoscale conditions associated with the 5 main precipitation patterns are identified as well as their seasonal characteristics. The annual cycle of precipitation in the region can be divided into a wet summer monsoon associated with the heavy precipitation patterns and a winter trade wind regime dominated by the lighter precipitation patterns. Precipitation in the winter trade wind regime has strong intraseasonal variability with high median precipitation totals in its early months and a steady decrease to very dry conditions by its end. Interannual variability in monthly precipitation during the summer monsoon season has a strong linear relationship with ENSO, while the intensity and latitude of the subtropical ridge is linearly related to precipitation during the trade wind season.