Document Type

Honors Thesis

Major

Marine Science

Advisor(s)

Margaret Estapa

Committee Members

Damian Brady, James Brophy, Patrick Gray

Graduation Year

May 2024

Publication Date

Spring 5-2024

Abstract

Current knowledge of dissolved organic carbon (DOC) in Maine estuaries is based on limited field research. By using chromophoric dissolved organic matter (CDOM) as a proxy, it is possible to use satellite images to estimate the concentration of DOC in an entire body of water. This study aims to evaluate different methods that calculate absorption by CDOM from ocean color remote sensing using images taken by Landsat 9 of the Sheepscot, Penobscot, and Damariscotta rivers. The study revealed that although there were some similarities in along-estuary trends between the remotely- sensed absorption and absorption measured in situ, the algorithms that were evaluated did not adequately replicate the in situ results. There was also a consistent offset between the spectral slope derived from remote sensing and the spectral slope measured in situ. The spectral slope calculated from remote sensing was consistently higher than the spectral slope measured in situ, which could indicate that the absorption values calculated from current remote sensing methods will be less accurate at shorter wavelengths. An explanation for the lack of accuracy in the remote sensing methods evaluated is that the assumptions made by the methods are not applicable to the Sheepscot, Penobscot, or Damariscotta rivers. Although this study does not have enough data to make any definitive statements on the effectiveness of current methods to derive absorption from remote sensing, it is clear that future research on this topic should focus on matching spectral slopes to those measured in situ.

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