Profile Soil Moisture Across Spatial Scales Under Different Hydroclimatic Conditions

Soil moisture statistics across spatial scales have been considered critical to various Earth Science applications. Soil moisture measurements are available only at very fine scale (at in situ monitoring facilities) or at very coarse scale (by satellite retrieval) on a regular basis. These measurements have extremely contrasting features in terms of temporal and spatial scales. Although no immediate technological solution is available to bridge the gap in real measurements at the intermediate support scales that can be substantiated, an alternative scaled representation of soil moisture using a newly developed modeling approach is proposed here. In this article, we investigated the characteristic features of profile soil moisture (at 1-, 10-, and 50-cm depths) statistics at different spatial resolutions (i.e., similar to 8, similar to 25, and similar to 60 km) modeled from scaled geophysical parameters and atmospheric forcings. We used Aqua satellite-based Advanced Microwave Scanning Radiometer (AMSR-E)-estimated soil moisture and local scale soil parameters to derive upscaled soil parameters for soil moisture modeling at the desired spatial scale. The soil moisture statistics including probability density functions (PDF) for multiple spatial resolutions and depths across the soil profile are presented for three contrasting hydroclimatic regions across the United States. These results could provide region-specific conditions for land-atmosphere interaction models and root zone soil moisture assimilation for various hydrologic and environmental applications.