Colored Dissolved Organic Matter (CDOM) is an important environmental marker in ocean water. The concentration (absorption) and spectral slope provide information about the source of the water. Consisting of organic dissolved material from various sources, it strongly absorbs light at blue and ultraviolet wavelengths, thereby influencing the energy available for phytoplankton, as well as overlapping with chlorophyll absorption spectra. This study models CDOM spectra based on satellite measurements of downwelling irradiance and water-leaving radiance. Samples measured in a laboratory setting are used to construct linear models that map ratios of radiance and irradiance values to CDOM absorption values. By fitting these extrapolated values to known mathematical models of CDOM spectra, an algorithm is developed for finding the CDOM spectral slope and reference absorption based on available remote-sensing quantities alone. Error bounds for the algorithm are determined by evaluating the root mean squared distance between the modeled and the reference samples. Using a second dataset linking spectral slope and absorption values to different CDOM types, a classification method is established to categorize a given unknown value from the remote sensing algorithm. The categorization method is then applied to Sentinel-3 and Landsat imagery, resulting in geospatial data extrapolating CDOM type from radiance values for each pixel of the image. The model results are compared to ground-truth data collected at sites located within the satellite image.
Furman, Adam, Kudela, Raphael, and Ayad, Mariam,
"Modeling CDOM Spectra from Satellite Measurements"
Summer Research Symposium.
Brown Digital Repository. Brown University Library.
Each year, Brown University showcases the research of its undergraduates at the Summer Research Symposium. More than half of the student-researchers are UTRA recipients, while others receive funding from a variety of Brown-administered and national programs and fellowships and go …