Evaluation of CMIP5 Precipitation Trends Across Multiple Scales

Water resources are changing in response to a changing climate. In order for water managers to make informed plans they need information about how precipitation trends may change. The degree to which climate models may be used for guidance, however, is the motivation for this work. Here, we ask: how well do the best performing climate models simulate existing precipitation trends at the catchment-scale? To address this question climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are compared to the Global Precipitation Climate Project (GPCP) dataset. The modelled precipitation trends will be validated globally, as well as over land and ocean, with the most representative models over land used for a comparison at the continental scale. The most representative models for each continent will then be compared to the Global Precipitation Climatology Centre (GPCC) rain gauge dataset over watersheds on each of the continents. This will determine how well the best performing climate models simulate existing precipitation trends. Insights into model performance will be gleaned from comparisons among the best performing models and ERA Interim Reanalysis products.