Floating Debris in the Northern Gulf of Mexico after Hurricane Katrina

Remote sensing and spectroscopy are usedto detect and quantifyfloating debris after a category-5 hurricane, paving the way for post-hurricaneenvironmental assessment using remote sensing techniques. Hurricane Katrina(category 5 with maximum wind of 280km/h whenthe eye is in the central Gulf of Mexico) made landfall near New Orleanson August 29, 2005, causing millions of cubic meters of disaster debris,severe flooding, and US$125 billion in damage. Yet, despite numerousreports on its environmental and economic impacts, little is knownabout how much debris has entered the marine environment. Here, usingsatellite images (MODIS, MERIS, and Landsat), airborne photographs,and imaging spectroscopy, we show the distribution, possible types,and amount of Katrina-induced debris in the northern Gulf of Mexico.Satellite images collected between August 30 and September 19 showelongated image features around the Mississippi River Delta in a regionbounded by 92.5 & DEG;W-87.5 & DEG;W and 27.8 & DEG;N-30.25 & DEG;N.Image spectroscopy and color appearance of these image features indicatethat they are likely dominated by driftwood (including constructionlumber) and dead plants (e.g., uprooted marsh) and possibly mixedwith plastics and other materials. The image sequence shows that ifaggregated together to completely cover the water surface, the maximaldebris area reached 21.7 km(2) on August 31 to the east ofthe delta, which drifted to the west following the ocean currents.When measured by area in satellite images, this perhaps representsa historical record of all previously reported floating debris dueto natural disasters such as hurricanes, floodings, and tsunamis.

Automated summary

Remote sensing and spectroscopy techniques were used to detect and quantify floating debris after Hurricane Katrina, providing a way for post-hurricane environmental assessment. Satellite images and imaging spectroscopy revealed the distribution and types of debris in the northern Gulf of Mexico, suggesting it was mainly composed of driftwood and dead plants mixed with plastics and other materials. The maximal debris area reached a historical record when measured by area in satellite images.