Bias adjustment and long-term verification of radar-based precipitation estimates

Quantitative Precipitation Estimates (QPE) based on weather radar observations are used more and more for water management, in Numerical Weather Prediction models, and for monitoring of severe weather. A straightforward method for bias adjustment of radar-based and hourly-updated precipitation accumulations is described. In addition a longterm verification of the bias-adjusted composites over a six year period using (in)dependent gauge data is presented. It is found that the adjustment scheme effectively removes the mean-field bias from the raw accumulations. The adjustment method cannot correct for a range-dependent bias and therefore it is recommended to also use a (simple) VPR adjustment procedure.