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Funded Research

Assessing Impacts and Monitoring Response of Coastal Wetlands to the Gulf Oil Spill

Ramsey, Elijah: USGS (Project Lead)
Jones, Cathleen: Jet Propultion Laboratory (Institution Lead)

Project Funding: 2012 - 2014

NRA: 2011 NASA: Terrestrial Ecology   

Funded by NASA

In response to the Deepwater Horizon oil spill, UAVSAR PolSAR data were collected of the Gulf of Mexico waters containing oil slicks near the spill site, and of inland waters and coastal wetlands potentially at risk of impact by the oil. Analyses of the 2010 PolSAR data found unique signatures within the oil spill potentially due to variations in oil properties and that are separable from ocean returns. We will extend this work to small scales by specifically tracking and characterizing oil signatures from the spill site transported into the coastal waterways and shorelines, near inland rigs, along pipelines, or on ships transporting oil to and from refineries. Tracking and characterization of oil near shorelines will be particularly important in order to establish the link between marsh impact and exposure to oil. Detecting changes brought about by oil injection into the marsh ecosystem is critical; however, in the dynamic coastal marshes it is often difficult to clearly identify the source of change. Analyses of both pre-spill 2009 and post-spill 2010 UAVSAR PolSAR scenes have produced confirmation of oil detection in marshes located along and in the near vicinity of impacted shorelines. A preponderance of evidence from the polarimetric decomposition products suggest oil impacts observed at the shorelines extended much further into the interior marshes. We will extend those analyses based on a small area of impacted coastal marshes to cover the majority of potentially impacted marshes of coastal Louisiana. Results of these analyses will provide a map of impacted, likely impacted, and non- impacted marshes. Two to three co-located and anniversary collections of PolSAR data will also provide an assessment of polarimetric products to identify changes related to oil occurrences and other biophysical changes. In support of oil occurrence mapping in coastal Louisiana marshes, this proposal adds another validation measure to assess whether analyses based on PolSAR data detected oil impacts in the interior marshes. A combination of 2010 ground-based measurements and polarimetric response signature analyses of indicator marshes throughout the central gulf coast showed for the first time the ability to structurally discriminate or separately map these important marsh types. Extending this to 2011 ground-based and PolSAR data provide a more representative baseline dataset for determining future change to wetlands in this region and elsewhere from detrimental impacts of oil spills and to linking results based on field data collected from non-impacted marshes to marshes likely impacted by oil. Analyses of nearly co-occurring AVIRIS and UAVSAR collections during the oil spill of impacted to non-impacted marshes will be used to assess the plausibility and value of an advanced radar-optical integrated system with improved optical pigment assessments and complete structural descriptions. Our work will determine whether more can be gained from the ecosystem monitoring effort through coordinated optical and radar collections over wetlands in the future. Although completed products have already advanced the state of knowledge of oil detection in wetlands and the linkage between marsh structures and polarimetric response signature, this proposal is put forward to ensure that the data already collected is completely analyzed to meet the science goals of the campaign and to improve wetland characterization with remote sensing in the future.

2013 NASA Terrestrial Ecology Science Team Meeting Poster(s)

  • Oil detection and latent impact monitoring in coastal marshes with polarimetric SAR   --   (Elijah Ramsey, Amina Rangoonwala, Cathleen Jones, Benjamin Holt)   [abstract]

More details may be found in the following project profile(s):