On Wednesday, April 2, 2003, the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite captured this clear image of the Middle East and surrounding countries. The most striking feature of the image is the large blackish-brown cloud of smoke blanketing Baghdad in the center of the image (see close up of Baghdad). Several thermal anomalies have been detected by MODIS—some in Baghdad and others in southern Iraq—and are marked with red dots.
It is not unusual for MODIS to detect thermal signatures at oil wells or refineries. Underground, great pressure keeps various flammable gases mixed in with the liquid oil. When the oil is brought to the surface where air pressure isn't as great, those gases bubble up out of the oil are typically burned off, giving off a thermal signature and sometimes smoke. Other processes of oil production and refinement produce detectable thermal signatures. The hot spots detected in a roughly diagonal line from the bottom right of the image may be from oil production and refinement. The plumes of smoke coming from the locations in southern Iraq, however, are larger than what MODIS typically sees.