AN ANALYTICAL FRAMEWORK FOR THE MODELING OF THE SPATIAL INTERACTION BETWEEN THE SOIL-MOISTURE AND THE ATMOSPHERE

Soil moisture-atmosphere interaction is recognized to play a role in t he dynamics of long-lasting spatial anomalies of continental climates. A simple analytical model is formulated and analysed, which represent s the soil moisture balance subjected to atmospheric forcing. The inte raction between the soil moisture and the atmosphere is included in th e form of a convolution integral, whose kernel represents the space-ti me feedbacks of the soil state on its own forcing. The conditions unde r which the model predicts the birth and growth of long-lasting spatia l soil moisture anomalies are studied. Particular properties of the fe edback kernel, such as the requirement of the simultaneous presence of an activation and an inhibition component, are identified. The existe nce of specific feedbacks of soil moisture on precipitation, as the ma in moisture forcing, is then addressed on the basis of some examples f rom the existing literature, with particular reference to the unforced convective and frontal-stratiform precipitation dynamics.