An animation of satellite images acquired by NASA’s Terra satellite about two and a half hours after AirAsia Flight QZ8501 lost contact. One is in true color the other in false color. (Source: NASA) | Update:
See the bottom of this post for a new image documenting thunderstorm activity in the area where AirAsia Flight 8501 lost contact with air traffic controllers, and links to additional information. Also, a big note of caution: We don’t know yet what happened. Weather may have played a role in the plane’s disappearance, but something else could have happened. We’ll just have to wait and hope that definitive evidence comes to light.
| As I'm writing this on Sunday morning in the U.S., the search for AirAsia Flight 8501 has been suspended for the night. The Airbus 320-200 aircraft took off from Surabaya, Indonesia with 162 people on board at 5.27 a.m. local time on Sunday, and then lost contact with air traffic controllers about two hours later. We don't know yet what happened, but questions have already been raised about what role, if any, weather conditions may have played in the disappearance of the aircraft. With that in mind, I thought I'd share some remote sensing images of the region showing what was happening on the morning of the plane's disappearance. I created the animation at the top of this post to show two satellite views of the region. They were acquired by NASA's Terra satellite about two and a half hours after the plane lost contact. The first is a true-color image with an area of thunderstorm activity circled. The second is a false-color version in which small ice crystals in high-level clouds appear in reddish-orange and peach tones. (This is the 3-6-7 composite on Terra's MODIS instrument. For more information, go here.) Here's an animation with a closer view:
True- and false-color satellite views of thunderstorm activity in the area where AirAsia Flight QZ8501 lost contact with air traffic controllers on Dec. 28, 2014. (Images: NASA. Animation: Tom Yulsman) If you look closely you can see the towering cauliflower-like heads of individual thunderstorm cells. I used the 3-6-7 false-color images in the animations because some experts have been speculating that icing of devices called "pitot tubes" could have played a role in whatever happened to the aircraft. John Goglia, who writes about the aviation industry for Forbes magazine, explains:
Pitot tubes are mounted near the nose of the airplane and measure the air force flowing through them as the aircraft moves through the atmosphere. These measurements are critical to ensuring proper air speed; flying too slowly can cause the plane to stall and flying too fast can cause a structural break up. If an aircraft encounters icing conditions at altitude – where moisture and very cold temperatures can combine – and icing forms on the pitot tubes, this can cause a blockage or partial blockage of one or more of the tubes. This in turn can lead to incorrect readings of the air speed.
Goglia points out that icing of pitot tubes were implicated in the crash of Air France Flight 447, an Airbus A-330 aircraft, on June 1, 2009 on a flight from Rio de Janiero to Paris. | Update 12/29/14: The Cooperative Institute for Meteorological Satellite Studies has posted new weather satellite imagery showing weather conditions at right around the time the AirAsia flight disappeared. Here's one example:
The MTSAT-2 weather satellite acquired this infrared image close to when the AirAsia flight disappeared. A circle indicates the approximate location of final contact with controllers. Singapore, the flight's destination, is labelled as "WSSS" in the upper left corner of the image. (Source: CIMSS) This infrared image from the MTSAT-2 satellite was acquired at 23:32 UTC — eight minutes after contact with the AirAsia aircraft was lost. According to the CIMSS post, this and other data indicate "that there were clusters of deep convection" in the area — meaning intense thunderstorm activity. That activity included a phenomenon known as "overshooting tops." This occurs when updrafts within a thunderstorm are so intense that air is propelled from the troposphere, the lowest atmospheric layer, into the stratosphere. As the CIMSS puts it:
Thunderstorms with OTs frequently produce hazardous weather at the Earth’s surface such as heavy rainfall, damaging winds, large hail, and tornadoes.
Weathergraphics.com also has posted imagery documenting the prevailing weather conditions when the AirAsia flight went missing. Check it out here. Lastly, let me repeat that cautionary note: We don't know yet what happened. The weather conditions I've documented here may have played a role in whatever happened to the aircraft — or not. Let's hope that time will tell. |