Precipitation in the EURO-CORDEX 0.11° and 0.44° simulations: high resolution, high benefits?

Abstract:

In the framework of the EURO-CORDEX initiative an ensemble of European-wide high resolution regional climate simulations on a 0.11° (~12.5 km) grid has been generated. This study investigates whether the high resolution regional climate models are able to add value to the simulated mean and extreme daily and sub-daily precipitation compared to their coarser resolution 0.44° (~50 km) counterparts. Therefore, pairs of low and high resolution simulations of 8 reanalysis driven models are compared to high resolution gridded observations in the Alps, Germany, Sweden, Norway, France, the Carpathians, and Spain. There is clear evidence that the 0.11° simulations are able to improve the representation of both mean and extreme precipitation in all regions and seasons, even on the spatial scale of the low resolution simulations (50 km grid). The 0.11° simulations are able to reduce biases in large areas of the investigated regions, have an improved representation of spatial precipitation patterns, and precipitation distributions are improved for daily and in particular for 3 hourly precipitation sums. When the evaluation is conducted on the high resolution (12.5 km) grid, the added value of the 0.11° models becomes even more obvious. The primary reason for these improvements seems to be better resolved orography, since most added value is found in and around mountainous regions.