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An Approach to Developing Numeric Nutrient Criteria for the Coastal Waters of the Northeast Using the Hyperspectral Imager for the Coastal Ocean (HICO)
Citation:
Keith, D., G. Thursby, AND S. Rego. An Approach to Developing Numeric Nutrient Criteria for the Coastal Waters of the Northeast Using the Hyperspectral Imager for the Coastal Ocean (HICO). International Space Station Research and Development Conference, Boston, MA, July 07 - 09, 2015.
Impact/Purpose:
This study proves that spectral data acquired from the Hyperspectral Imager for the Coastal Ocean (HICO) on the International Space Station (ISS) can be transformed in water quality information in support of nutrient criteria development in coastal and estuarine systems. During his study, data products were input into a regionally calibrated seagrass bio-optical model to predict and map spatial and temporal patterns in water clarity based on light attenuation and secchi depth for Narragansett Bay. This application of space-based information represents another example of how remotely sensed data can assist state and federal clients in sustainable management practices and inform the general public about water quality conditions.
Description:
The Clean Water Act requires states to identify designated uses of their waters and when necessary develop science-based water quality criteria to ensure protection of the designated uses. Designated uses include recreation, fish consumption, shellfish harvesting and drinking water sources. Thresholds for water quality criteria are set to provide an expectation that classes of designated uses will be supported and protected. One of the Environmental Protection Agency’s (EPA) key priorities is a national strategy for development of numeric nutrient criteria which identifies total nitrogen (TN) and total phosphorus (TP) as causal variables and dissolved oxygen and chlorophyll a (chl a) as nutrient-related response variables. This research project is part of a larger Agency effort to expand nutrient-related response variables to include other indicators such as water column incident light penetration (i.e., water clarity) in coastal and estuarine waters. This response variable would support healthy seagrass habitats, fish consumption, shellfish harvesting, and recreational activities.The Hyperspectral Imager for the Coastal Ocean (HICO) imaging instrument, onboard the International Space Station, offers EPA the opportunity to model the quality and quantity light in the water column in Northeastern waters with initial emphasis on the Narragansett Bay (Rhode Island) estuarine system. Using atmospherically corrected images, apparent (e.g., remote sensing reflectance (Rrs)) optical properties were retrieved and used to derive bio-optical models which estimated chl a concentrations, colored dissolved organic matter (CDOM) absorption and total suspended solids (TSS) concentrations. The chl a, CDOM absorption, and TSS estimates were then input into a regionally calibrated seagrass bio-optical model to successfully predict and map spatial and temporal patterns in water clarity based on light attenuation and secchi depth for Narragansett Bay.