Investigating Soil Moisture–Convective Precipitation Feedbacks Using In Situ Soil Moisture in the Central United States

Soil moisture can affect precipitation, however there is significant debate about the sign and strength of soil moisture-precipitation coupling. The purpose of this study is to examine the relationship between soil moisture and convective initiation. The goal is to determine whether convective initiation occurs preferentially over dry or wet soil. In situ soil moisture from the central United States (2005-2007) are derived from the North American Soil Moisture Database. The Thunderstorm Observation by Radar (ThoR) algorithm is used to identify the initiation of unorganized convective events. Three criterion are used to define the spatial representativeness of each in situ measurement location. All of the convective events occurring within a representative distance from each station are analyzed to evaluate whether there is a preference for convection to initiate over dry or wet soil. The results based on different criterion are compared to illustrate the sensitivity. We also examine the impacts of spatial scale on soil moisture-convective precipitation interactions. Flux data are used to identify the physical mechanisms of the feedback process. This study will enhance understanding of land-atmosphere interactions and how the land surface influences convective initiation.