Abstract:
Hurricane Katrina (category 5 with maximum wind of 280 km/h when the eye is in the central Gulf of Mexico) made landfall near New Orleans on August 29, 2005, causing millions of cubic meters of disaster debris, severe flooding, and US$125 billion in damage. Yet, despite numerous reports on its environmental and economic impacts, little is known about how much debris has entered the marine environment. Here, using satellite 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 show elongated image features around the Mississippi River Delta in a region bounded by 92.5°W-87.5°W and 27.8°N-30.25°N. Image spectroscopy and color appearance of these image features indicate that they are likely dominated by driftwood (including construction lumber) and dead plants (e.g., uprooted marsh) and possibly mixed with plastics and other materials. The image sequence shows that if aggregated together to completely cover the water surface, the maximal debris area reached 21.7 km2 on August 31 to the east of the delta, which drifted to the west following the ocean currents. When measured by area in satellite images, this perhaps represents a historical record of all previously reported floating debris due to natural disasters such as hurricanes, floodings, and tsunamis.
摘要:
2005年8月29日,卡特里娜飓风(当眼睛在墨西哥湾中部时,最大风速为280公里/小时的5级)在新奥尔良附近登陆,造成数百万立方米的灾难碎片,严重洪水,和1250亿美元的损失。然而,尽管有许多关于其环境和经济影响的报道,人们对有多少碎片进入海洋环境知之甚少。这里,使用卫星图像(MODIS,MERIS,和Landsat),机载照片,和成像光谱学,我们展示了分布,可能的类型,以及墨西哥湾北部卡特里娜飓风引起的碎片数量。8月30日至9月19日之间收集的卫星图像显示了密西西比河三角洲周围92.5°W-87.5°W和27.8°N-30.25°N的区域内的细长图像特征。这些图像特征的图像光谱学和颜色外观表明,它们可能由浮木(包括建筑木材)和死植物(例如,连根拔起的沼泽),并可能与塑料和其他材料混合。图像序列显示,如果聚集在一起完全覆盖水面,8月31日,三角洲以东的最大碎片面积达到21.7平方公里,随着洋流向西漂移。当按卫星图像中的面积测量时,这可能代表了以前报道的所有由于飓风等自然灾害而漂浮的碎片的历史记录,洪水,和海啸。