Understanding the Role of Land-Atmosphere Interaction on Soil Moisture Persistence
摘要
Droughts are one of the extremes that pose severe threats to biodiversity and future food security as they occur over large areas and long periods. Drought evolves with space and time due to land-atmospheric feedback and soil moisture plays a pivotal role in governing the feedback. As soil desiccates during droughts, it reduces latent heat flux and increases sensible heat flux, warming up the atmospheric boundary layer. The persistence in soil moisture plays a critical role in the extent of propagation of droughts and can therefore be useful in improving seasonal climate predictions. We use a simple mass balance model to analyze the effect of land-atmospheric interactions on soil moisture persistence. First, we run the model by ignoring the land-atmospheric interaction and assuming atmospheric water demand solely as a function of net radiation. Then, we introduce the interaction by using a simplified relationship.