Skip to main content
ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Publications at this Location » Publication #377456

Research Project: Integrating Remote Sensing, Measurements and Modeling for Multi-Scale Assessment of Water Availability, Use, and Quality in Agroecosystems

Location: Hydrology and Remote Sensing Laboratory

Title: SMAP detects soil moisture under temperate forest canopies

item COLLIANDER, A. - Jet Propulsion Laboratory
item Cosh, Michael
item KELLY, V. - Cary Institute Of Ecosystem Studies
item KRAATZ, S. - University Of New Hampshire
item BOURGEAU-CHAVEZ, L. - Michigan Technological University
item SIQUEIRA, P. - University Of Massachusetts, Amherst
item ROY, A. - University Of Quebec
item KONINGS, A. - Stanford University
item HOLTZMAN, N. - Stanford University
item MISRA, S. - National Aeronautics And Space Administration (NASA)
item ENTEKHABI, D. - Massachusetts Institute Of Technology
item O'NEILL, P. - National Aeronautics And Space Administration (NASA)
item YUEH, S. - Jet Propulsion Laboratory

Submitted to: Geophysical Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2020
Publication Date: 9/21/2020
Citation: Colliander, A., Cosh, M.H., Kelly, V., Kraatz, S., Bourgeau-Chavez, L., Siqueira, P., Roy, A., Konings, A., Holtzman, N., Misra, S., Entekhabi, D., O'Neill, P.E., Yueh, S. 2020. SMAP detects soil moisture under temperate forest canopies. Geophysical Research Letters. 47(19):e2020GL089697.

Interpretive Summary: Soil moisture remote sensing products are limited by the ability of the sensor to view the soil surface through dense vegetation. Because of this limitation, remote sensing products usually do not result in a soil moisture estimate for forests and other dense agricultural crops. We describe an experiment to study soil moisture under dense vegetation and mixed forest-agriculture landscapes. Initial results demonstrate that a soil moisture product can be developed with reduced but acceptable accuracies for these landscapes. More research is necessary to extend this work to other forests, but this study is the first demonstration of dense vegetation retrievals of soil moisture from a satellite platform.

Technical Abstract: Soil moisture dynamics in the presence of dense vegetation canopies are determinants of ecosystem function and biogeochemical cycles, but the capability of existing spaceborne sensors to support reliable and useful estimates is not known. New results from a recently initiated field experiment in the northeast United States show that the NASA SMAP (Soil Moisture Active Passive) satellite is capable of retrieving soil moisture under temperate forest canopies. We present an analysis demonstrating that a parameterized emission model with the SMAP morning overpass brightness temperature resulted in a RMSD (root mean square difference) range of 0.047-0.057 m3/m3 and a Pearson correlation range of 0.75-0.85 depending on the experiment location and the SMAP polarization. The inversion approach included a minimal amount of ancillary data. This result demonstrates unequivocally that spaceborne L-band radiometry is sensitive to soil moisture under temperate forest canopies, which has been uncertain because of lack of representative reference data.