Myanmarâ€™s Delta: Water World from NYTimes Dot Earth Blog
The team managing the data flowing from instruments on NASAâ€™s Terra satellite has posted a pair of images of the Irrawaddy River delta in Myanmar before and after Cyclone Nargis struck, showing vividly the amount of land that was submerged.
Flood water can be difficult to see in photo-like satellite images, particularly when the water is muddy. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASAâ€™s Terra satellite use a combination of visible and infrared light to make floodwaters obvious. Water is blue or nearly black, vegetation is bright green, bare ground is tan, and clouds are white or light blue.
On April 15, rivers and lakes are sharply defined against a backdrop of vegetation and fallow agricultural landâ€¦. The wetlands near the shore are a deep blue green. Cyclone Nargis came ashore across the mouths of the Irrawaddy and followed the coastline northeast. The entire coastal plain is flooded in the May 5 image. The fallow agricultural areas appear to have been especially hard hit. For example, YangÃ´n (population over 4 million) is almost completely surrounded by floods. Several large cities (population 100,000â€“500,000) are in the affected area. Muddy runoff colors the Gulf of Martaban turquoise.