The effectiveness of using MODIS products to map sea surface oil

This project describes the effectiveness of using standard Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and products, produced by NASA and distributed through the Distributed Active Archive Centers (DAACs), to monitor and map oil on the surface of the Gulf of Mexico from the oil release at the Deepwater Horizon site. With twice daily coverage of the Gulf of Mexico and the rest of the world, MODIS is well suited to monitor the effects of these types of incidents on the sea surface. MODIS imagery has been widely used by many federal, state, and local agencies, as well as the media and non-government groups to illustrate the distribution and movement of surface oil. The MODIS products evaluated for their effectiveness in mapping and monitoring oil and the sea surface include: imagery, sea surface temperature (available for nighttime and daytime temperatures), chlorophyll concentration, particulate organic/inorganic carbon, chromophoric dissolved organic matter index, diffuse attenuation coefficient, and remote sensing reflectance. These products were chosen because they are available on a daily basis. Some MODIS standard products are only available as eight-day composites which would not be as useful for monitoring a feature as dynamic as oil moving on the sea surface. MODIS standard products are produced by applying atmospheric corrections and algorithms to selected bands of MODIS data. The bands primarily used for ocean products are bands 8-16 which have a spatial resolution of 1 km. Additional products may be evaluated. The Deepwater Horizon oil rig exploded and caught fire on April 20, 2010. The drilling platform sank several days later. The well ruptured at the seafloor, 5000 feet below the sea surface, and began leaking a combination of crude oil and natural gas. As of July 15, 2010, the oil leak was capped. The Deepwater Horizon site is located approximately 58 miles southeast of the mouth of the Mississippi River in southeastern Louisiana. The effectiveness of the MODIS products was determined by comparing the MODIS data with surface water samples and digital photography taken aboard the research vessel Pelican between May 5 and May 15, 2010 within the Gulf of Mexico. During that scientific mission, the presence or lack of surface oil was reported, coordinate locations were recorded, and water and oil samples were collected. The majority of these samples were taken within 10 miles of the Deepwater Horizon site, while some were taken up to 72 miles away. During the research trip aboard the Pelican, the surface oil was not consistently present in some areas, but tended to shift due to wind and currents. Particular sites have a useful temporal aspect since they were repeatedly visited for sampling. Sun glint areas on MODIS true color imagery make surface oil especially evident. It is anticipated that the MODIS standard products will detect the oil on the sea surface that is not evident in the visible portion of the imagery spectra.