Peggy O’Neill
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View article: Thermal Hydraulic Disaggregation of SMAP Soil Moisture Over the Continental United States
Thermal Hydraulic Disaggregation of SMAP Soil Moisture Over the Continental United States Open
A thermal hydraulic disaggregation of soil moisture (THySM) algorithm was implemented to downscale NASA's soil moisture active passive (SMAP) enhanced soil moisture (SM) product to 1 km over the continental United States (CONUS). This algo…
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: Validation of Soil Moisture Data Products from the NASA SMAP Mission
Validation of Soil Moisture Data Products from the NASA SMAP Mission Open
NASA’s 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 set of criteria for core validation sites (…
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
NASA’s 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 set of criteria for core validation sites (…
View article: Assessing Disaggregated SMAP Soil Moisture Products in the United States
Assessing Disaggregated SMAP Soil Moisture Products in the United States Open
A soil moisture (SM) disaggregation algorithm based on thermal inertia (TI) theory was implemented to downscale the soil moisture active passive (SMAP) enhanced product (SPL2SMP$\_$E) from 9 to 1 km over the continental United States. The …
View article: SMAP Detects Soil Moisture Under Temperate Forest Canopies
SMAP Detects Soil Moisture Under Temperate Forest Canopies Open
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. …
View article: Appraisal of SMAP Operational Soil Moisture Product from a Global Perspective
Appraisal of SMAP Operational Soil Moisture Product from a Global Perspective Open
Space-borne soil moisture (SM) satellite products such as those available from Soil Moisture Active Passive (SMAP) offer unique opportunities for global and frequent monitoring of SM and also to understand its spatiotemporal variability. T…
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: How Satellite Soil Moisture Data Can Help to Monitor the Impacts of Climate Change: SMAP Case Studies
How Satellite Soil Moisture Data Can Help to Monitor the Impacts of Climate Change: SMAP Case Studies Open
Socially and economically costly extreme weather events have become more prevalent in the last decade. Monitoring and early warning systems could help mitigate the impact of such events by allowing people to better prepare themselves to ma…
View article: Seasonal Dependence of SMAP Radiometer-Based Soil Moisture Performance as Observed Over Core Validation Sites
Seasonal Dependence of SMAP Radiometer-Based Soil Moisture Performance as Observed Over Core Validation Sites Open
The NASA SMAP (Soil Moisture Active Passive) mission provides a global coverage of soil moisture measurements based on its L-band microwave radiometer every 2-3 days at about 40 km resolution. The soil moisture retrieval algorithms model t…
View article: SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture - Global
SMAP/Sentinel-1 L2 Radiometer/Radar 30-Second Scene 3 km EASE-Grid Soil Moisture - Global Open
This Level-2 (L2) soil moisture product provides estimates of land surface conditions retrieved by both the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes and the Sentin…
View article: HIGH-RESOLUTION ENHANCED PRODUCT BASED ON SMAP ACTIVE-PASSIVE APPROACH USING SENTINEL 1A AND 1B SAR DATA
HIGH-RESOLUTION ENHANCED PRODUCT BASED ON SMAP ACTIVE-PASSIVE APPROACH USING SENTINEL 1A AND 1B SAR DATA Open
SMAP project released a new enhanced high-resolution (3km) soil moisture active-passive product. This product is obtained by combining the SMAP radiometer data and the Sentinel-1A and -1B Synthetic Aperture Radar (SAR) data. The approach u…
View article: Physics-Based Retrieval of Surface Roughness Parameters for Bare Soils from Combined Active-Passive Microwave Signatures
Physics-Based Retrieval of Surface Roughness Parameters for Bare Soils from Combined Active-Passive Microwave Signatures Open
In the past the effect of soil roughness was often considered secondary within the determination of soil moisture from remote sensing data. Several studies showed that accurate determination of soil roughness leads to an improved estimatio…
View article: Determination of Best Low-Frequency Microwave Antenna Approach For Future High Resolution Measurements From Space
Determination of Best Low-Frequency Microwave Antenna Approach For Future High Resolution Measurements From Space Open
Microwave remote sensing measurements at L-band (~1.2-1.6 GHz) of geophysical parameters such as soil moisture will need to be at higher spatial resolution than current systems (SMOS/ SMAP/ Aquarius) in order to meet the requirements of la…
View article: Polarization Decomposition and Temperature Bias Resolution for Smap Passive Soil Moisture Retrieval Using Time Series Brightness Temperature Observations
Polarization Decomposition and Temperature Bias Resolution for Smap Passive Soil Moisture Retrieval Using Time Series Brightness Temperature Observations Open
In passive microwave remote sensing of soil moisture, the tau-omega (-) model has often been used to provide soil moisture estimates at a spatial scale representative of the satellite footprint dimensions. For modeling simplicity, model pa…
View article: Development and validation of the SMAP enhanced passive soil moisture product
Development and validation of the SMAP enhanced passive soil moisture product Open
Since the beginning of its routine science operation in March 2015, the NASA SMAP observatory has been returning interference-mitigated brightness temperature observations at L-band (1.41 GHz) frequency from space. The resulting data enabl…
View article: Nasa soil moisture active passive mission status and science highlights
Nasa soil moisture active passive mission status and science highlights Open
The Soil Moisture Active Passive (SMAP) observatory was launched January 31, 2015, and its L-band radiometer and radar instruments became operational during April 2015. This paper provides a summary of the quality assessment of its baselin…
View article: Soil moisture retrieval with airborne PALS instrument over agricultural areas in SMAPVEX16
Soil moisture retrieval with airborne PALS instrument over agricultural areas in SMAPVEX16 Open
NASA's SMAP (Soil Moisture Active Passive) calibration and validation program revealed that the soil moisture products are experiencing difficulties in meeting the mission requirements in certain agricultural areas. Therefore, the mission …
View article: Combined Radar–Radiometer Surface Soil Moisture and Roughness Estimation
Combined Radar–Radiometer Surface Soil Moisture and Roughness Estimation Open
A robust physics-based combined radar-radiometer, or Active-Passive, surface soil moisture and roughness estimation methodology is presented. Soil moisture and roughness retrieval is performed via optimization, i.e., minimization, of a joi…
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…
View article: SMAP L-Band Microwave Radiometer: Instrument Design and First Year on Orbit
SMAP L-Band Microwave Radiometer: Instrument Design and First Year on Orbit Open
The Soil Moisture Active-Passive (SMAP) L-band microwave radiometer is a conical scanning instrument designed to measure soil moisture with 4% volumetric accuracy at 40-km spatial resolution. SMAP is NASA's first Earth Systematic Mission d…
View article: Development of VHF (240–270 MHz) antennas for SoOp (signal of opportunity) receiver for 6U Cubesat platforms
Development of VHF (240–270 MHz) antennas for SoOp (signal of opportunity) receiver for 6U Cubesat platforms Open
The main goal of this research is to design, fabricate, and test deployable VHF antennas for 6U Cubesat platforms to enable validation of root zone soil moisture (RZSM) estimation algorithms for signal of opportunity (SoOp) remote sensing …