title: Geospatial estimation of the impact of Deepwater Horizon oil spill on plant oiling along the Louisiana shorelines.
abstract: Stranded oil covering soil and plant stems in fragile Louisiana marshes was one of the most visible impacts of the 2010 Deepwater Horizon (DWH) oil spill. As part of the assessment of marsh injury after the DWH spill, plant stem oiling was broken into five categories (0%, 0-10%, 10-50%, 50-90%, 90-100%) and used as the independent variable for estimating death of vegetation, accelerated erosion, and other metrics of injury. The length of shoreline falling into each of these stem oiling categories was therefore a key measure of the total extent of marsh injury, and its accurate estimation is the focus of this paper. First, we used geographically-weighted logistic regression (GWR) to explore and model spatially varying relationships between stem oiling field data and secondary information (oiling exposure category) collected during shoreline surveys. We then combined GWR probability estimates with field data using indicator cokriging to predict the probability of exceeding four stem oiling thresholds (0, 10, 50, and 90%) at 50 m intervals along the Louisiana shoreline. Cross-validation using Receiver Operating Characteristic (ROC) Curves demonstrate the greater prediction accuracy of the multivariate geostatistical approach relative to either aspatial regression or indicator kriging that ignores secondary information.
authors.affiliation: PGeostat LLC, Jerome, MI 49249, USA. Electronic address: goovaerts.pierre@gmail.com.
authors.forename: Pierre
authors.initials: P
authors.lastname: Goovaerts
authors.affiliation: Abt Associates, Boulder, CO 80302, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: Wobus
authors.affiliation: Abt Associates, Boulder, CO 80302, USA.
authors.forename: Russell
authors.initials: R
authors.lastname: Jones
authors.affiliation: Abt Associates, Boulder, CO 80302, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Rissing
mesh_terms: D004190:Disasters; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation; D060851:Gulf of America; D006801:Humans; D008145:Louisiana; D009792:Oceans and Seas; D059392:Petroleum Pollution; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D053833:Wetlands
chemical_list: D014874:Water Pollutants, Chemical
keywords: Cokriging; False positives; Geographically-weighted regression; Indicator kriging; Marsh