Assessing the evaporation-precipitation feedback in CMIP5 models

Abstract:

Land-atmosphere interactions are recognized as a major component of the physical climate system. One of the key features of those interactions is the feedback of soil moisture on precipitation, which reflects the coupling between soil moisture and evapotranspiration on the one hand, and between evapotranspiration and precipitation on the other hand. Global climate models have been known to show large uncertainties in the simulation of this coupling – in particular regarding the latter, atmospheric branch. Here we use the TFS metric (developed by Findell et al. 2011) to characterize these uncertainties, investigating the simulated sensitivity of precipitation to surface turbulent fluxes in CMIP5 models (in present climate): this analysis assesses the impact of evaporative fraction on the frequency and intensity of convective rainfall at the sub-daily time scale. Beyond geographical patterns, the relationship between background climate, evaporative regimes and the simulated coupling is analyzed. Particular attention is also given to the interaction between the representation of the diurnal cycle of precipitation and the diagnosed evaporation-precipitation in the models.