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STUDY TITLE: Remote Sensing Assessment of Surface Oil Transport and Fate during 

Spills in the Gulf of Mexico 

REPORT TITLE: Synthesis Report

CONTRACT NUMBER: M12PC00003

SPONSORING OCS REGION: Gulf of Mexico

APPLICABLE PLANNING AREA(S): Western, Central, and Eastern

FISCAL YEAR(S) OF PROJECT FUNDING: 2012–2016

COMPLETION DATE OF REPORT: 25 May 2016 (draft)

COSTS: FY 2013: $146,621; FY 2014: $319,269; FY 2015: $224,419; FY 2016 (to date 

through July 2016): $95,276 CUMULATIVE PROJECT COST TO DATE: $785,585

PROJECT MANAGER(S): Ian R. MacDonald

AFFILIATION: Dept. of Earth Ocean and Atmospheric Science, Florida State University

ADDRESS: Mail Stop 4320, Florida State University, Tallahassee, FL 32306

PRINCIPAL INVESTIGATOR(S)

*

: Ian MacDonald, Oscar Garcia-Pineda, Dmitry 

Dukhovskoy, Steve Morey, Mark Bourassa, Mark Reed, Jørgen Skencke, Chuanmin Hu 

KEY WORDS: Oil Spills, Hydrocarbons, Remote Sensing, Modeling, Deepwater 

Horizon, Lagrangian Coherent Structure, Oil Weathering

BACKGROUND: The goal of this study was to help fill gaps in our understanding of the 

mechanisms controlling surface oil movement during spills, particularly at small spatial 

scales. Oil spill motion and fate is affected by a variety of physical and chemical 

processes, including spreading, currents and advection, turbulent diffusion, winds, 

wave-induced mixing, and oil weathering such as through emulsification and 

evaporation. The impact of the various physical and chemical processes on spill 

transport depends on the type of oil involved or released and oceanographic conditions. 

Movement of surface oil in the eastern Gulf of Mexico (GoM) is also heavily impacted by 

the Loop Current and cyclonic, anticyclonic, and frontal eddies. For example, one gap in 

our understanding is quantification of material boundaries or their proxy, Lagrangian 

coherent structures, which may or not be crossed by oil depending on winds and 

boundary strength. These can include convergence zones, freshwater-saltwater 

interfaces, and velocity shear. The penetrability of these material boundaries partly 

 

*

Principal Investigators’ affiliations may be different from the Project Manager.
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determines whether spilled oil crosses into the Loop Current or the freshwater lens 

around the Mississippi River delta. Also, different results for oil transport can be 

obtained through modifying parameterizations of wind effects. Appropriate values for the 

weights used in estimating wind-induced oil spill speed and the deflection angle suitable 

for the GoM deserve further analysis. These wind parameterizations would be of 

particular importance during high-wind events.

Remote sensing products and ocean circulation models together can provide crucial 

information on the oceanographic processes determining the location and spread of 

surface oil. During spill response activities, imagery and hydrodynamic models are used 

by government agencies for mapping the extent of the surface spill and describing the 

impact of oceanographic features on spill movement. BOEM also continually seeks to 

improve understanding of how oil spills interact with oceanographic processes in the 

GoM to inform its Oil Spill Risk Analysis and environmental needs. A variety of satellite 

and overflight products can contribute to these analyses, including infrared sea surface 

temperature, ocean color, high resolution visible red-green-blue, altimetric sea surface 

height, Synthetic Aperture Radar (SAR), and multispectral airborne imagery. Remote 

sensing algorithms are in various stages of development for characterizing oil location 

and thickness and each method has its strengths and weaknesses. For example, recent 

results show that the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is a 

useful tool for quantifying oil thickness for "thick" oils within a certain size range, while 

use of ocean color sensors, such as the Moderate Resolution Imaging 

Spectroradiometer (MODIS), are better for identifying oil sheens. A wealth of remote 

sensing, overflight, and in situ measurements have been collected during past spill 

events in the GoM. These observations, in conjunction with physical forcing fields, need 

to be analyzed in greater detail to more precisely quantify wind and ocean current 

forcing on oil spill movement.

OBJECTIVES: 1) To characterize surface oil distributions through remote sensing 

techniques; 2) To develop an oil transport and weathering model and physical forcing 

fields for analyzing surface oil distributions; 3) To describe the effects of oceanographic 

and wind forcing on the transport and character of oil; and 4) To identify different mixing 

processes which influence surface oil transport.

DESCRIPTION: The project entitled Wind and Advection Modeling for Oil Spill 

Transport (WAMOST) was a multi-disciplinary effort conducted by researchers at the 

Florida State University, University of South Florida, and the Norwegian Technical and 

Industrial Research Institute-Stiftelsen for Industriell og Teknisk Forskning (SINTEF). 

During the Deepwater Horizon (DwH) emergency, the scientific community produced a 

number of impromptu forecasts of surface oil drift to complement those performed by 

the federal agencies. These results were used to guide the oil cleanup operations in the 

Gulf and, after the spill emergency had passed, to inform investigations of oil fate and 

effects for assessment of damages. Major sources of uncertainty in the oil spill forecasts 
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stemmed from the absence of reliable initialization data and uncertainties plaguing 

surface oil drift models. Many of these predictions used Lagrangian oil drift models 

without weathering processes, but SINTEF has developed a well-regarded weathering 

model known as OSCAR (Oil Spill Contingency and Response). Oil particle advection 

outcomes from the SINTEF OSCAR model were compared to results from models 

developed by the Center for Ocean Atmospheric Prediction Studies and a significant 

adaptation of the OSCAR model was implemented to capture the chemical state and 

relative age of oil particles. Most surface oil drift models combine wind effect and ocean 

surface currents to estimate drift of oil (typically modeled as discrete Lagrangian 

particles representative of fixed quantities of oil) in the ocean. Generally, calculation of 

oil trajectories employs ocean surface currents derived from hydrodynamic models. 

Though oil surface drift occurs at the very surface of the ocean, what are termed

“surface currents” simulated in a hydrodynamic model more precisely represent the 

velocity integrated (or averaged) throughout the topmost vertical layer, which may be 

several meters thick depending on the discrete vertical resolution. The WAMOST 

results were able to implement and validate alternative approaches for estimation of the 

surface ocean currents that are crucial to accurate modeling of surface oil transport 

from hydrodynamic model velocity fields and near-surface winds. Many existing 

methods for oil transport estimates ignore the influence of wave-driven transport. The 

WAMOST team investigated this to gain better understanding on limitations and 

advantages of using surface wave drift in oil forecasting. The implemented model 

considered contributions to surface roughness from three types of surface features that 

include an aerodynamically smooth surface, capillary waves, and gravity waves. Results 

informed the following objectives: (1) Identification of material boundaries in the GoM; 

(2) Analysis of oil mixing across the boundaries; (3) Quantification of critical strength 

values to define permeability of the material boundaries to surface oil.

SIGNIFICANT CONCLUSIONS: Results of work carried out during the WAMOST 

project advance the state of the art for remote sensing of oil by improving the methods 

for detection of floating oil and in understanding the influences of environmental factors 

such as wind and currents that spread and dissipate surface slicks. Remote sensing 

data provided a means for tracking a critical component of this discharge: movement of 

oil across the ocean surface. It is this component of the DwH oil spill (Figure 1) that 

generated contaminated marine snow, injured mesophotic corals, and oiled over 2100 

km of the Gulf coast. 
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Figure 1. Map of surface oil from DwH visible to SAR: Distribution and average volume of surface 

oil (m3km-2) from DwH discharge; gridded at 5x5 km scale, across a cumulative footprint of 

149,000 km2, 24 April–3 August 2010.

The structure of the near-surface velocity profile and the related dynamics still remain a 

fundamental knowledge gap for simulating surface oil transport. Results from this 

project demonstrate the differences in how hydrodynamic models represent surface 

velocity given their numerical schemes and vertical grid discretization, as well as the 

impact Stokes drift can have in inducing current shear at the surface. There is a lack of 

velocity observations within the upper few meters of the ocean surface making this a 

difficult area of study. However, recent and upcoming advances in observing this 

surface layer shear provide great opportunities for further research aimed at improving 

understanding of the near-surface physics, which should in turn allow improvements to 

be made in estimating the “true” surface current from upper layer model currents when 

applied to oil drift simulations.

The DwH oil spill provided valuable data for understanding the weathering of oil. 

However, this event occurred during a time of year in which surface waters and air 

temperatures of the Gulf were very warm and incoming solar radiation was at its 

maximum. Though oil was entrained in the Loop Current, the relatively rapid weathering 

of oil prevented significant amounts of actionable or observable oil from traveling to

great distances. The DwH oil was also light compared to some well-studied oil spills in 

colder climates, such as Exxon Valdez, in which oil remained for much longer periods of 

time. Thus, it is not clear how the fate of the oil released during the DwH spill would 
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have been different had the event happened during the winter when northern Gulf water 

and air temperatures can be more than 15° C colder, and shortwave radiation is only 

about one third of that in the warm months. 

Results from this research and recently published research by others (e.g., Kourafalou 

and Androulidakis 2013) show that strong salinity gradients may serve as constraints to 

oil transport. These interactions between oil and salinity gradients are poorly observed, 

however. Further research should be conducted to develop better techniques of 

characterizing these features from remotely sensed data, including recent surface 

salinity observations from the Soil Moisture Active Passive satellite, and in the use of 

other radiometric satellite sensors to detect small-scale oceanographic features in the 

presence of surface oil.

The actual surface current is likely substantially greater than the velocity in the top layer 

of the ocean model. Atmospheric models solve this problem by parameterizing the wind 

profile in the layer close to the surface. A similar approach can be used in an ocean 

model, but observations of surface currents (and ideally near surface shear) are needed 

to determine which parameterizations and conditions are appropriate. In the last year in 

situ and remotely sensed technologies have been developed to measure the surface 

current. These technologies should be used to gather the data needed to determine 

appropriate parameterizations, and a model of the current shear near the ocean surface 

should be added to the models.

Two-way coupled ocean-wave-atmosphere models now exist and could be used to 

examine the importance of this coupling in assessing flow transport. Preliminary work 

suggests that this coupling has non-negligible impacts on transport.

STUDY RESULTS: The project resulted in the following peer-reviewed papers 

published, in print, or submitted, and in presentations at professional meetings including 

those listed below.

Publications

Clark M, Heath N, Bourassa MA. 2015. Quantification of Stokes drift as a mechanism 

for surface oil advection in the Gulf of Mexico. J Geophys Res. (accepted, pending 

minor revisions)

Daneshgar Asl, S., J. F. Amos, P. Woods, O. Garcia-Pineda and I. R. MacDonald 2015. 

"Chronic, anthropogenic hydrocarbon discharges in the Gulf of Mexico." Deep Sea 

Research Part II: Topical Studies in Oceanography 129: 187–195.

Daneshgar Asl, S., D. Dukhovskoy, M. Bourassa and I. R. MacDonald 2017. "Hindcast 

modeling of oil slick persistence from natural seeps." Remote Sens Environ. 

189(February 2017): 96–107.

Dukhovskoy DS, Leben RR, Chassignet EP, Hall C, Morey SL, Nedbor-Gross R. 2015. 

Characterization of the uncertainty of Loop Current metrics using a multidecadal 

numerical simulation and altimeter observations. Deep-Sea Res Pt I. 100: 140–158
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Dukhovskoy DS, Ubnoske J, Blanchard-Wrigglesworth E, Hiester HR, Proshutinsky A. 

2015. Skill metrics for evaluation and comparison of sea ice models. J Geophys 

Res. 120, 5910–5931

Garcia-Pineda O, MacDonald I, Hu C, Svejkovsky J, Hess M, Dukhovskoy D, Morey SL. 

2013. Detection of floating oil anomalies from the Deepwater Horizon oil spill with 

synthetic aperture radar. Oceanography. 26(2): 124–137.

Garcia-Pineda, O, MacDonald IR, Li X, Jackson CR, Pichel WG. 2013. Oil spill mapping 

and measurement in the Gulf of Mexico with Textural Classifier Neural Network 

Algorithm (TCNNA). IEEE J Sel Top Appl Earth Obs Remote Sens. PP(99): 2517–

2525.

Garcia-Pineda OG, MacDonald IR, Shedd W. 2014. Analysis of oil volume fluxes of 

hydrocarbon seep formations on the Green Canyon and Mississippi Canyon: a study 

using 3D-seismic attributes in combination with satellite and acoustic data. SPE 

Reservoir Eval Eng, 17(4): 430–435

GRIIDC: Gulf of Mexico Research Initiative Information and Data Cooperative 

Database. Corpus Christi (TX). Neural network analysis determination of oil slick 

distribution and thickness from satellite Synthetic Aperture Radar, April 24 - August 

3, 2010 [revised 2016 Jan 21; accessed 2016 Jan 21] 

https://data.gulfresearchinitiative.org/data/R1.x132.137:0045/.

Hiester HR, Morey SL, Dukhovskoy DS, Chassignet EP, Kourafalou VH, Hu C. 2016. A 

topological approach for quantitative comparisons of ocean model fields to satellite 

ocean color data. Methods Oceanography, In Review.

Hu C, Chen S, Wang M, Murch B, Taylor J. 2015. Detecting surface oil slicks using 

VIIRS nighttime imagery under moon glint: a case study in the Gulf of Mexico. 

Remote Sens Lett. 6:295–301.

Hu C, Feng L, Holmes J, Swayze GA, Leifer I, Melton C, Garcia O, MacDonald I, Hess 

M, Muller-Karger F, Graettinger G, Green R. 2016. Remote sensing estimation of 

surface oil volume during the 2010 Deepwater Horizon oil blowout in the Gulf of 

Mexico: Scaling up AVIRIS observation with MODIS measurements. Int J Remote 

Sens. Submitted

Lu Y, Sun S, Zhang M, Murch B, Hu C. 2016. Refinement of the critical angle 

calculation for the contrast reversal of oil slicks under sunglint. J Geophys Res 

Oceans. 121(1): 148–161

MacDonald IR. 2013. Tracking Recovery from Deepwater Horizon. Sea Tech. 54(5): 23-

30.

MacDonald IR, Garcia-Pineda OM, Beet A, Daneshgar Asl S, Feng L, French McCay 

DP, Graettinger G, Holmes J, Hu C, Leifer I, Mueller-Karger F, Solow AR, Swayze 

G. 2015. Natural and unnatural oil slicks in the Gulf of Mexico. J Geophys Res 

Oceans. 120(12): 8364–8380.

MacDonald, I.R., Kammen DM, Fan M. 2014. Science in the aftermath: investigations of 

the DWH hydrocarbon discharge. Environ Res Lett. 9(12): 125006.

Özgökmen TM, Chassignet EP, Dawson C, Dukhovskoy D, Jacobs G, Ledwell J, 

Garcia-Pineda O, MacDonald I, Morey SL, Olascoaga M, Poje AC, Reed M, 

Skancke J. 2016. Over what area did the oil and gas spread during the 2010 

Deepwater Horizon oil spill? Oceanography. In Review.
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Sun S, Hu C. 2016. Sun glint requirement for the remote detection of surface oil films. 

Geophys Res Lett. 43: 309–316.

Sun S, Hu C, Feng L, Swayze GA, Holmes J, Graettinger, MacDonald I, Garcia O, 

Leifer I. 2016) Oil slick morphology derived from AVIRIS measurements of the 

Deepwater Horizon oil spill: Implications for spatial resolution requirements of 

remote sensors. Mar Pollut Bull. 103(102): 276–285.

Sun S, Hu C, Tunnell Jr. JW. 2015. Surface oil footprint and trajectory of the Ixtoc-I oil 

spill determined from Landsat/MSS and CZCS observations. Mar Pollut Bull. 

101:632–641.

Wang M, Hu C. 2015. Extracting oil slick features from VIIRS nighttime imagery using a 

Gaussian filter and morphological constraints. IEEE Geosci Remote Sens Lett. 

12(10): 2051–2055.

Presentations

Morey, S.L., D.S. Dukhovskoy, H. Hiester, O. Garcia–Pineda, and I. MacDonald (2015), 

Application of a topological metric for assessing numerical ocean models with 

satellite observations, 2015 AGU Fall Meeting, San Francisco.

Dukhovskoy, D.S. and J. Ubnoske (2013), Sea ice model evaluation: A topological 

approach, FAMOS workshop, Woods Hole. 

Dukhovskoy, D.S., O. Garcia, I. MacDonald, S.L. Morey, J. Ubnoske (2013), Objective 

Evaluation of Surface Oil Drift Simulation Using SAR Imagery, 13th International 

Conference on Estuaring and Coastal Modeling, San Diego.

MacDonald, I.R., et al., A comprehensive time-series of surface oil during DWH. 2015 

Gulf of Mexico Oil Spill and Ecosystem Science Conference, 2015. Houston, Tx(16-

19 Feb. 2015).

MacDonald, I.R., et al., A Time-Series of Surface Oil Distribution Detected by Satellite 

SAR During the Deepwater Horizon Blowout AGU Fall Meeting, San Francisco, CA, 

2013. OS21D-03(Oral Presentation).

MacDonald, I., S. Daneshgar Asl, and O.M. Garcia Pineda, Surface oil drift rates 

estimated from natural seeps, in 2013 Gulf of Mexico Oil Spill and Ecosystem 

Science Conference 2013: New Orleans, LA.

Jan 21–23, 2013, New Orleans, LA, Gulf of Mexico Oil Spill & Ecosystem Science 

Conference. Co-chaired session 18 “Remote sensing and the deep water horizon oil 

spill” (with Duane Armstrong, Eric Lindstrom, and Ian MacDonald). Gave an oral 

presentation: “Satellite remote sensing of the Deepwater Horizon oil spill: What have 

we learned with MODIS and MERIS?” by C. Hu

March 18–20, 2013. 3rd EOS Topical Meeting on Blue Photonics – Optics in the Sea 

(Blue Photonics 3), Royal Netherlands Institute for Sea Research (NIOZ), Texel, 

Netherlands, 18-20 March 2013, “Visibility of oil dispersed in seawater in windy 

conditions” by Otremba, Z., O. Zielinski, and C. Hu.

Oct 23–26, 2013, 2013 Frontiers in Education Conference. Oral presentation: “Realworld problem solving in software development: A case study on the Deepwater 

Horizon oil spill” by Zhang, M., C. Hu, and G. Amu.

Jan 27–29, 2014, 2014 Gulf of Mexico Oil Spill & Ecosystem Science Conference. 

Mobile, Alabama, U.S.A., Presentation: Establish a satellite-based virtual buoy 

system for coastal water quality monitoring and decision support, by C. Hu et al.
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May 5–7, 2014, NASA Ocean Color Research Meeting, Silver Spring, MA. Presentation: 

“A multi-sensor assessment of the DwH oil spill: surface expression and volume” by 

C. Hu

February 16-19, 2015, GoMRI Oil Spill & Ecosystem Science Conference in Houston, 

Texas, presented the following poster:

Sun, S., and C. Hu (2015). On the challenge of remote estimation of surface oil volume 

in the ocean: Examples from satellite and airborne measurements

Garcia-Pineda OG, MacDonald IR. Analysis of the BP Oil Spill Deep Water Horizon 

Extent Using Synthetic Aperture Radar Satellite Imagery. in 2013 Gulf of Mexico Oil 

Spill & Ecosystem Science Conference 2013. New Orleans LA: Gulf of Mexico 

Research Initiative. Sept 28, 2015, Invited seminar at TAMU (departments of 

oceanography & atmosphere):

Hu, C. (2015). From algal blooms, oil spills, to global biology Feb 1 – 4, 2016, Gulf of 

Mexico Oil Spill & Ecosystem Science Conference, Tampa, FL. Presentation: 

Surface oil footprint and trajectory of the Ixtoc-I oil spill determined from 

Landsat/MSS and CZCS observations by Sun, S., C. Hu, and J. W. Tunnell, Jr.

Poster: Sun glint requirement for the remote detection of surface oil films by Sun, S. and 

C. Hu

Shi, Q., M. A Bourassa and P. Velissariou, 2015: Investigating the effect of ocean 

currents on the surface stress and heat fluxes over the Gulf of Mexico using a twoway coupled modeling system. 2015 AGU Fall Meeting. December, San Francisco, 

California

Bourassa, M. A., S. Daneshgar-Asl, M. Clark, Y. Zheng, and P. J. Hughes, 2014: 

Effects of oceanographic, wind and wave forcing on surface oil. WAMOST Mid-Term 

Meeting. Jan., Mobile, Alabama.

Bourassa, M. A., Y, Zheng, and P. J. Hughes, 2014: Influences of Sea Surface 

Temperature Gradients and Surface Roughness Changes on the Motion of Surface 

Oil: A Simple Idealized Study. 31st Conference on Hurricanes and Tropical 

Meteorology, April, San Diego, California. 

Bourassa, M. A., 2013: Surface fluxes. Workshop on Developing Science Objectives for 

Satellite Mission. Oct., Boulder, Colorado. 

Clark, M,, and M. Bourassa, 2013: Quantitative Investigation of Stokes Drift as a 

Surface Transport Mechanism for Oil: Progress and Future. Deep-C All Hands 

Meeting, Sept. Tallahassee, Florida.

Persechino, A., T. Shropshire, M. A. Bourassa, D. Dukhovskoy, S. L. Morey, 2013: 

Using Satellite Chlorophyll-a concentration to validate salinity fields in NCOM & 

HYCOM around the Mississippi River mouth during the oil spill event of 2010. DeepC All Hands Meeting, September, Tallahassee, Florida.

Steffen, J., and M. Bourassa, 2013: Winds over Oil: A comparison of data from satellite, 

buoys, and gridded products. Deep-C All Hands Meeting, Sept., Tallahassee, 

Florida. 

Zheng, Y., M.A. Bourassa, and P. Hughes, 2013: Impacts of Sea Surface Temperature 

Gradients and Surface Roughness Changes on the Motion of Surface Oil: A Simple 

Idealized Study. 2013 International Ocean Vector Winds Science Team Meeting. 

May, Kailua-Kona, Hawaii.
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Zheng, Y., M.A. Bourassa, and P. Hughes, 2013: Influence of sea surface temperature 

gradient and roughness changes due to a slick on the motion of surface oil: A simple 

idealized study. Deep-C "All Hands" Meeting, March, Tallahassee, Florida.

STUDY PRODUCT(S): Dukhovskoy, D., Bourassa, M., Morey, S. Hu, C., Reed, M. 

Skancke, J. and MacDonald, I. Remote Sensing Assessment of Surface Oil Transport 

and Fate during Spills in the Gulf of Mexico, Synthesis Report. US Dept. of the Interior, 

Bureau of Ocean Energy Management, Gulf of Mexico OCS Region, New Orleans. 

OCS Study BOEM 2017-030. 134 p.