R. S. Dunbar
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View article: Assessment of Surface Fractional Water Impacts on SMAP Soil Moisture Retrieval
Assessment of Surface Fractional Water Impacts on SMAP Soil Moisture Retrieval Open
Fractional water (FW) correction of satellite microwave brightness temperature (Tb) observations is a prerequisite for accurate soil moisture (SM) mapping over mixed land and water areas. Here, we evaluated the FW impacts on NASA Soil Mois…
View article: Validation of Soil Moisture Data Products From the NASA SMAP Mission
Validation of Soil Moisture Data Products From the NASA SMAP Mission Open
The National Aeronautics and Space Administration Soil Moisture Active Passive (SMAP) mission has been validating its soil moisture (SM) products since the start of data production on March 31, 2015. Prior to launch, the mission defined a …
View article: Regularized Dual-Channel Algorithm for the Retrieval of Soil Moisture and Vegetation Optical Depth From SMAP Measurements
Regularized Dual-Channel Algorithm for the Retrieval of Soil Moisture and Vegetation Optical Depth From SMAP Measurements Open
In August 2020, soil moisture active passive (SMAP) released a new version of its soil moisture and vegetation optical depth (VOD) retrieval products. In this article, we review the methodology followed by the SMAP regularized dual-channel…
View article: Eyes on the Storms: JPL’s Tropical Cyclone Information System
Eyes on the Storms: JPL’s Tropical Cyclone Information System Open
An unusual number of tropical systems in the Atlantic, captured in this TCIS visualization, were all evolving simultaneously on 15 September during the record-breaking 2020 hurricane season.
View article: Soil Moisture Active/Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration Revisit: Approach and Performance
Soil Moisture Active/Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration Revisit: Approach and Performance Open
The soil moisture active passive (SMAP) microwave radiometer is a fully-polarimetric L-band radiometer flown on the SMAP satellite in a 6 AM /6 PM sun-synchronous orbit at 685-km altitude. After the SMAP L1B_TB data product version 4 was r…
View article: An Eye on the Storm: Integrating a Wealth of Data for Quickly Advancing the Physical Understanding and Forecasting of Tropical Cyclones
An Eye on the Storm: Integrating a Wealth of Data for Quickly Advancing the Physical Understanding and Forecasting of Tropical Cyclones Open
Tropical cyclones (TCs) are among the most destructive natural phenomena with huge societal and economic impact. They form and evolve as the result of complex multiscale processes and nonlinear interactions. Even today the understanding an…
View article: Improved SMAP Dual-Channel Algorithm for the Retrieval of Soil Moisture
Improved SMAP Dual-Channel Algorithm for the Retrieval of Soil Moisture Open
The soil moisture active passive (SMAP) mission was designed to acquire L-band radiometer measurements for the estimation of soil moisture (SM) with an average ubRMSD of not more than 0.04 m3 m-3 volumetric accuracy in the top 5 cm for veg…
View article: Comprehensive analysis of alternative downscaled soil moisture products
Comprehensive analysis of alternative downscaled soil moisture products Open
Recent advances in L-band passive microwave remote sensing provide an unprecedented opportunity to monitor soil moisture at ~40 km spatial resolution around the globe. Nevertheless, retrieval of the accurate high spatial resolution soil mo…
View article: Global Assessment of the SMAP Freeze/Thaw Data Record and Regional Applications for Detecting Spring Onset and Frost Events
Global Assessment of the SMAP Freeze/Thaw Data Record and Regional Applications for Detecting Spring Onset and Frost Events Open
More than half of the global land area undergoes seasonal frozen and thawed conditions that constrain eco-hydrological processes. The freeze-thaw (FT) retrieval from satellite microwave remote sensing detects landscape changes between froz…
View article: Soil Moisture Active/Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration Upgrade
Soil Moisture Active/Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration Upgrade Open
Current performance and existing problems in SMAP radiometer L1B_TB version 3 data product are described. The post-launch calibration algorithm has been updated by calibrating the three calibration parameters (the equivalent noise temperat…
View article: Comparison of downscaling techniques for high resolution soil moisture mapping
Comparison of downscaling techniques for high resolution soil moisture mapping Open
Soil moisture impacts exchanges of water, energy and carbon fluxes between\nthe land surface and the atmosphere. Passive microwave remote sensing at L-band\ncan capture spatial and temporal patterns of soil moisture in the landscape.\nBoth…
View article: Joint Sentinel‐1 and SMAP data assimilation to improve soil moisture estimates
Joint Sentinel‐1 and SMAP data assimilation to improve soil moisture estimates Open
SMAP (Soil Moisture Active and Passive) radiometer observations at ∼40 km resolution are routinely assimilated into the NASA Catchment Land Surface Model to generate the 9 km SMAP Level‐4 Soil Moisture product. This study demonstrates that…
View article: Validation of SMAP surface soil moisture products with core validation sites
Validation of SMAP surface soil moisture products with core validation sites Open
The NASA Soil Moisture Active Passive (SMAP) mission has utilized a set of core validation sites as the primary methodology in assessing the soil moisture retrieval algorithm performance. Those sites provide well-calibrated in situ soil mo…