A soil moisture assimilation scheme using satellite-retrieved skin temperature in meso-scale weather forecast model

A thermodynamically consistent soil moisture assimilation scheme for clear sky and snow free conditions has been developed for the meso-scale modeling system in the Arctic region by using satellite-derived skin temperatures. Parallel control and sensitivity modeling experiments were designed and their results demonstrated that the assimilation scheme successfully improves the soil moistures that were deliberately perturbed initially, indicating capability of the scheme to correct bias in the soil moisture initialization. Moreover, the resultant benefit of this assimilation scheme does not only lie in the improvement of soil moisture; the skin temperature also consequently exhibits improvements in a thermodynamic consistency. A real application of the assimilation scheme with satellite-retrieved skin temperature exhibited noticeable positive impacts on the modeling simulation and weather forecast; the model obviously captured meso-scale features of soil moistures as well as the skin temperatures. The warming tendency bias in original model simulations was removed to a considerable extent by this assimilation scheme.