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David J. Williams
Researcher at United States Environmental Protection Agency
Publications - 15
Citations - 534
David J. Williams is an academic researcher from United States Environmental Protection Agency. The author has contributed to research in topics: Soil water & Soil carbon. The author has an hindex of 9, co-authored 14 publications receiving 367 citations. Previous affiliations of David J. Williams include Research Triangle Park.
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Journal ArticleDOI
National Urban Database and Access Portal Tool
Jason Ching,Michael J. Brown,Steven J. Burian,Fei Chen,Ron Cionco,Adel Hanna,Torrin Hultgren,Timothy N. McPherson,David J. Sailor,Haider Taha,David J. Williams +10 more
TL;DR: The National Urban Database and Access Portal Tool (NUDAPT) as mentioned in this paper was developed by the U.S. Environmental Protection Agency to produce and provide gridded fields of urban canopy parameters for various new and advanced descriptions of model physics.
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Evaluating Sentinel-5P TROPOMI tropospheric NO2 column densities with airborne and Pandora spectrometers near New York City and Long Island Sound
Laura M. Judd,Jassim A. Al-Saadi,James Szykman,L. Valin,Scott J. Janz,Matthew G. Kowalewski,Matthew G. Kowalewski,Henk Eskes,J. Pepijn Veefkind,J. Pepijn Veefkind,Alexander Cede,Moritz Mueller,Manuel Gebetsberger,Robert J. Swap,R. Bradley Pierce,Caroline R. Nowlan,G. Gonzalez Abad,Amin R. Nehrir,David J. Williams +18 more
TL;DR: Airborne and ground-based Pandora spectrometer NO2 column measurements were collected during the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) in the New York City/Long Island Sound region, which coincided with early observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) instrument.
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Preliminary investigation of submerged aquatic vegetation mapping using hyperspectral remote sensing.
TL;DR: The use of airborne hyperspectral remote sensing imagery for automated mapping of submerged aquatic vegetation (SAV) in the tidal Potomac River was investigated for near to real-time resource assessment and monitoring.
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Is biochar-manure co-compost a better solution for soil health improvement and N2O emissions mitigation?
Yinghong Yuan,Huaihai Chen,Huaihai Chen,Wenqiao Yuan,David J. Williams,John T. Walker,Wei Shi +6 more
TL;DR: The data demonstrated that the biochar-chicken manure co-compost could substantially reduce soil N2O emissions compared to chicken manure compost, via controls on soil organic C stabilization and the activities of microbial functional groups, especially bacterial denitrifiers.
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Evaluating the impact of spatial resolution on tropospheric NO 2 column comparisons within urban areas using high-resolution airborne data
Laura M. Judd,Jassim A. Al-Saadi,Scott J. Janz,Matthew G. Kowalewski,Matthew G. Kowalewski,R. Bradley Pierce,James Szykman,L. Valin,Robert J. Swap,Alexander Cede,Moritz Mueller,Martin Tiefengraber,Nader Abuhassan,Nader Abuhassan,David J. Williams +14 more
TL;DR: This work explores best practices for satellite validation strategies with Pandora direct-sun observations by showing the sensitivity to product spatial resolution and demonstrating how the high spatial resolution NO2 data retrieved from airborne spectrometers, such as GeoTASO, can be used with high temporal resolution ground-based column observations to evaluate the influence of spatial heterogeneity on validation results.