| Soil moisture-precipitation feedback is crucial in understanding land-atmosphere interactions. A lack of observations of soil moisture and precipitation at the same spatial scale makes it difficult to quantify the feedback and determine the proper spatial scale to detect this phenomenon. The goal of this study is to portray the soil moisture-precipitation relationship at a daily time scale across the continental United States (CONUS) during June, July, and August using the North American Regional Reanalysis (NARR) dataset (1979-2014). Following the framework established by Findell and Eltahir in 2003, the convective triggering potential (CTP), low-level humidity index (HI), and soil moisture conditions observed at 1200 UTC, as well as afternoon convective precipitation, are used to assess the soil moisture-precipitation relationship depicted by the NARR dataset. Convective precipitation occurred most frequently in the southeastern United States (US). When precipitation occurred, optimal values of CTP (100-300 J/kg) and HI (5-15 K) were indicated, which supports instability and moisture as factors for convection to occur. The Kolmogorov-Smirnov test displayed a significant difference in soil moisture fraction on rain days and non-rain days across many areas of the US. The Great Plains and parts of the southeast US experienced drier soil conditions on days with rain, while the Northeast, experienced wetter conditions. These results indicated that both wet and dry soil moisture conditions may contribute to convective precipitation in different regions with different climate conditions. |
