[Seminar on Nov 15] Mean and Extreme Precipitation over European River Basins Better Simulated in a 25km AGCM
Dr. Reinhard Schiemann
National Centre for Atmospheric Science,
University of Reading, UK
Room 1118, New Building, IAP
10am, Nov. 15, 2018
In this presentation, I will first briefly introduce the UK High Resolution Global Climate Modelling Collaboration between the National Centre of Atmospheric Science and the Met Office, including the current simulations and analyses carried out as part of the PRIMAVERA project, the European contribution to CMIP6-HighResMIP. In the main part of the presentation, I will present a specific model evaluation for European mean and extreme precipitation that could be extended to other parts of the world such as China:
The representation of European mean and extreme precipitation is evaluated in simulations with an atmospheric GCM (AGCM) at different resolutions between about 135 and 25km grid spacing in the mid-latitudes. The continent-wide RMS error in mean precipitation in the 25km model is about 25% smaller than in the 135km model in winter. Clear improvements are also seen in autumn and spring, whereas the model's sensitivity to resolution is very small in summer. Extreme precipitation is evaluated by estimating generalised extreme value distributions (GEVs) of daily precipitation aggregated over river basins whose surface area is greater than 50000 km2. A sensitivity experiment is conducted showing that these resolution sensitivities in both mean and extreme precipitation are in many areas primarily due to the increase in resolution of the model orography. The findings of this study illustrate the improved capability of a global high-resolution model in simulating European mean and extreme precipitation.