Publications by authors named "David D Graybill"

The lateral transport of dissolved organic carbon (DOC) is crucial in tidal marsh carbon budgets, but estimating DOC remains a challenge due to the dynamic nature of terrestrial-aquatic interfaces and limitations of observations. This study used a linear model to correlate DOC and chromophoric dissolved organic matter (CDOM) absorption coefficient at 440 nm ( ; ) in Bald Head Creek, North Carolina, USA. Modeled DOC concentrations were merged with current velocity derived from the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) to estimate daily DOC fluxes from January to April 2021, representing winter and spring in the mid-latitude northern hemisphere.

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Seagrasses have been widely recognized for their ecosystem services, but traditional seagrass monitoring approaches emphasizing ground and aerial observations are costly, time-consuming, and lack standardization across datasets. This study leveraged satellite imagery from Maxar's WorldView-2 and WorldView-3 high spatial resolution, commercial satellite platforms to provide a consistent classification approach for monitoring seagrass at eleven study areas across the continental United States, representing geographically, ecologically, and climatically diverse regions. A single satellite image was selected at each of the eleven study areas to correspond temporally to reference data representing seagrass coverage and was classified into four general classes: land, seagrass, no seagrass, and no data.

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Seagrass meadows are degraded globally and continue to decline in areal extent due to human pressures and climate change. This study used the bio-optical model GrassLight to explore the impact of climate change and anthropogenic stressors on seagrass extent, leaf area index (LAI) and belowground organic carbon (BGC) in St. Joseph Bay, Florida, using water quality data and remotely-sensed sea surface temperature (SST) from 2002 to 2020.

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Satellite image artefacts are features that appear in an image but not in the original imaged object and can negatively impact the interpretation of satellite data. Vertical artefacts are linear features oriented in the along-track direction of an image system and can present as either banding or striping; banding are features with a consistent width, and striping are features with inconsistent widths. This study used high-resolution data from DigitalGlobe's (now Maxar) WorldView-3 satellite collected at Lake Okeechobee, Florida (FL), on 30 August 2017.

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