Temporal and spatial resolution requirements for a soil moisture mission

The temporal and spatial resolution requirements for a soil moisture mission are addressed through a synthetic identical twin data assimilation study. Simulations were made for observations with various temporal resolutions (1, 2, 3, 5, 10, 15, 20 and 30 days), and spatial resolutions (0.5, 6, 12 18, 30, 60 and 120 minutes of arc). It was found that daily observations of surface soil moisture achieved the best predictions of soil moisture and evapotranspiration, with the greatest impact of temporal resolution being for 1 to 5 days. It was also found that observations with a spatial resolution less than the model resolution produced the best results, with spatial resolutions greater than the model resolution yielding only a slight degradation.