Abstract
Water held in soil can be returned to the atmosphere via two main processes – evaporation from the soil surface, and transpiration via plants which can extract moisture at lower soil levels. Combined, this flux is referred to as evapotranspiration and is the dominant component of the latent heat flux from the surface. The magnitude and timing of this flux can influence the evolution of the state of the atmosphere in such a way that it exacerbates extremes. Dry soils, in particular, are known to modulate heat waves.
This report details the results of experiments assimilating satellite measurements of soil moisture into the land surface model JULES. We used a novel, ensemble-based data assimilation methodology to tune the soil hydraulics in JULES so that the model predictions of soil moisture more closely match those of the European Space Agency Climate Change Initiative (ESA CCI) soil moisture data set. We test the model predictions outside of the assimilation window to show that the improvement in model skill persists in time.
