Temperature and extreme soil moisture relationships in Subseasonal Experiment project (SubX) forecast models and their impact on heatwave prediction

Abstract:

Due to the increasing frequency of heatwave activity over the United States, an extensive analysis of observations and reanalysis data has been carried out to determine the role of land-atmosphere interactions in the relationship between soil moisture and temperature extremes. Regime shifts in the sensitivity of atmospheric temperature to soil moisture desiccation have been discovered, its distribution across the US, and the role of surface fluxes have been detailed. This study investigates the retrospective forecast model dataset from the Subseasonal Experiment project (SubX) to determine the sensitivity of atmospheric temperature to soil moisture changes in forecast models, and to draw comparisons to the results found in the study of observations and reanalysis data. Model representation of land-atmosphere interactions and the spatial distribution of sensitivity are also explored. The effect of model drift during the course of forecasts and the potential impact of soil moisture initialization is also quantified. Accurate representation of breakpoint estimates and corresponding metrices of land-atmosphere coupling can lead to improvements in heatwave prediction across the SubX models. This study also provides a novel approach to model evaluation that would be fruitful for predictability research.