Impacts of soil moisture initialization and memory on subseasonal forecast skill over North America

Soil moisture affects the evolution of weather through modulation of land-atmosphere coupling and feedbacks. Because of its persistence characteristics, accurate soil moisture initialization can contribute to subseasonal forecast skill. In the Global Land-Atmosphere Coupling Experiments (GLACE and GLACE-2), strong land-atmosphere coupling was found over the Great Plains of North America. However, the contribution of realistic soil moisture initialization to subseasonal temperature forecast skill in that area was small compared to much of the rest of the continent. This study aims to explain this discrepancy and reveal the mechanism behind it.