Australia’s 2012 bushfire season has burned through the dry winter and into early spring, consuming thousands of hectares of vegetation across Western Australia and Northern Territory. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite passed over the region on September 18 and captured this pair of images at 5:00 UTC (2:30 p.m. CDT). Western Australia lies to the west, and the Northern Territory lies to the east.
The top image is a false-color image, created from bands 7, 3 and 1 of the 36 spectral bands of data collected by the MODIS instrument. In this combination of bands, growing vegetation appears lime green, earth appears tan and ocean appears dark blue to midnight black. Sediment near the surface of the ocean appears brilliant blue. The red marks indicate hotspots, areas where the thermal sensors on the MODIS instrument detect temperatures higher than background, and in this case the hotspots are primarily actively burning fires. In many areas, the fires ring dark areas which indicate fire scars.
Rolling the cursor over the top image reveals the true-color image of the same event, created by combining bands 1, 4 and three. This combination gives an image similar to that seen by the human eye. In this image, the spring growth of vegetation can only be seen where it grows the thickest, and the landscape appears primarily tan. Sediment appears tan, but where it sinks in the ocean, it is cannot be seen. The hotspots appear the same in this image, but the fire scars blend into the background more than in the false-color image. Smoke, which blows strongly from many fires, is more easily seen in the true-color image.
The silvery-gray area in the upper left of the image is sunglint. It is an area where light reflects off the surface of the ocean at the same angle the instrument is viewing the surface.