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Estimating Chlorophyll Conditions in Southern New England Coastal Waters from Hyperspectral Aircraft Remote Sensing
Citation:
KEITH, D. J. Estimating Chlorophyll Conditions in Southern New England Coastal Waters from Hyperspectral Aircraft Remote Sensing. Chapter 7, Remote Sensing of Coastal Environment. CRC Press LLC, Boca Raton, FL, , 152-172, (2010).
Impact/Purpose:
This manuscript describes the development of a predictive model derived from in situ hyperspectral data from Narragansett Bay and remote sensing reflectance (RSR) in the red portion of the spectrum to estimate the concentration of chlorophyll a in coastal waters. Hyperspectral RSR data collected via aircraft are then applied to the model to predict chlorophyll concentrations along Narragansett Bay, Providence River, Buzzards Bay, and Long Island Sound. The chlorophyll estimations are used to assess the condition of 26 bays and estuaries along the southern New England coast using National Coastal Assessment guidelines for chlorophyll The impacts of this manuscript are twofold. First, an algorithm is created which accurately predicts chlorophyll concentrations in coastal waters from remotely sensed data. It is well recognized in the scientific literature that the standard remote sensing algorithms presently used to estimate chlorophyll a concentrations from the blue:green portion of the visible spectrum perform poorly in coastal and estuarine waters. Secondly, this method is important because it represents a step forward in how aircraft remote sensing data can be used in an assessment framework to evaluate environmental condition on spatial scales and time periods that add value to monitoring programs.
Description:
Chlorophyll a (chl a) is commonly measured in water quality monitoring programs for coastal and freshwater systems. The concentration of chl a, when evaluated with other condition indicators such as water clarity and dissolved oxygen concentrations, provides information on the environmental quality of estuaries and coastal waters and the extent to which coastal habitats and resources have been altered. In this paper, the ecological condition of numerous individual embayments and estuaries along the southern New England coast, as well as the adjoining coastal ocean, is determined over an annual cycle using remote sensing data and the criteria for assessing chlorophyll a concentrations found in EPA National Coastal Assessment guidelines. An empirically-derived, band ratio model developed from in situ hyperspectral data was developed and applied to remotely sensed, hyperspectral data passively acquired during aerial surveys to estimate surface concentrations of chl a along the southern New England coastline. These estimations were used to assess environmental condition for individual coastal systems and create site-specific annual assessments which were aggregated to create a regional assessment at monthly, seasonal and annual scales.