Usefulness of very-high-resolution simulations for a national climate service

A set of 7-month-long simulations for 5 different years has been performed with the convection-permitting regional climate model Harmonie-Climate in the extremely fine resolution of 750 m grid distance. The simulations are double-nested with an intermediate 5 km domain covering Denmark, the North Sea and Baltic Sea as well as southern Norway and Sweden. The high-resolution domain covers Denmark and the very south of Sweden.We investigate precipitation, temperature, and other variables, comparing the two nests with observation and with the EURO-CORDEX ensemble in order to estimate the added value from such costly very-high-resolution model simulations wrt. climate services, specifically Klimaatlas, the DanishNational Climate Atlas. Extreme precipitation has been compared for a set of model simulations covering a wide range of resolutions. While the realism of models increases with resolution in general, the properties of extreme precipitation does not scale entirely as expected.