Satellite images add to weight of evidence locating missing MH370
New evidence in the investigation into the fate of Flight MH370 has emerged that supports oceanographic analysis pointing to the location of the missing aircraft.
High-resolution images from an Airbus Pleiades 1A satellite showing “probably man-made” objects similar to debris items since found, were taken on 23 March 2014, a little more than two weeks after the passenger airline went missing in the Indian Ocean.
Geoscience Australia completed new analysis earlier this year and the location of the objects in the images at the time of the crash was estimated by CSIRO using drift analysis. GA’s and CSIRO’s reports to ATSB are released today.
It is the third oceanographic report by CSIRO on the likely location of MH370 which disappeared on 8 March 2014 with 227 passengers and 12 crew on board.
This imagery adds to the cumulative weight of evidence based on plane debris found in 2015 on Île de la Réunion and later along the African coast, as well as the absence of any debris on Australia’s west coast.
CSIRO’s Dr David Griffin says it makes his team increasingly confident about a more precise likely crash site, more confident still than their last reported estimate provided in April 2017.
Oceanographic research has continued since the underwater search was suspended in January this year.
While the initial surface search for missing flight MH370 was underway in March 2014, several high-resolution surveillance satellites were tasked to take images of the ocean near the 7th arc.
Many objects of interest were to be seen in several of the images from a wide range of locations but nothing was recovered.
Four of the images have recently been re-examined by Geoscience Australia.
GA concluded that the images captured by the Airbus Pleiades 1A satellite showed 12 objects that were “probably man-made” and 28 that were “possibly man-made”.
The CSIRO report says: The dimensions of these objects are comparable with some of the debris items that have washed up on African beaches and their location near the 7th arc makes them impossible to ignore….If at least some objects in the images are pieces of 9M-MRO, from where did they drift in the weeks between the disappearance of the aircraft and image capture?
What makes this finding particularly interesting is that the images were located not far from the location identified by CSIRO oceanographic analysis in earlier reports to the ATSB as the likely crash site.
Indeed, Griffin says CSIRO’s drift modelling shows that the objects were seen about as close to their predicted location as could be reasonably expected, given the uncertainties involved with modelling the drift of items at the sea surface.
As he explains, some Earth observation satellites map swathes of the Earth’s surface like a lawnmower, where others can be tasked to look at one place at a time in great detail.
These satellite images available to the team at GA were taken at 0.5m resolution over an area of 20.5km x 20km, 100km apart.
CSIRO used sea surface height data from altimetry satellites to create daily maps of the surface currents. They used those current maps to backtrack the object locations from 23 March to 8 March, the day the plane went missing presumed crashed.
Joining the dots
The new report makes the point that this latest investigation required a very detailed knowledge of the surface currents “out in the middle of the ocean where almost no in-situ observations have ever been made”.
The advantage for oceanographers this time was that the drift modelling only had to be applied to a two-week window – a much shorter interval than the many months relating to all the other evidence. This allowed for much greater precision.
The oceanographic work by CSIRO has progressively incorporated new evidence as it has become available. In December 2016, based on debris found on Reunion and along the African coast, Griffin and his team reported to the ATSB putting the likely crash site between 36 degrees and 32.5 degrees South latitude. Testing of a real Boeing 777 flaperon in water earlier this year, with results reported to the ATSB in April, confirmed with increased confidence the recommended search area.
This time they were able to use the same drift modelling to prioritise a subregion of the search area delineated by other clues.
“Each step of these three reports has made the establishment of where it is more and more precise,’’ Griffin says.
How precise? The report places the mostly likely location of the aircraft “with unprecedented precision and certainty” at 35.6°S, 92.8°E, a location consistent with the new information as well as all the other available clues to the location of the aircraft. It is not a unique location, but the other two candidates (34.7°S 92.6°E and 35.3°S 91.8°E) are not far away.
This knowledge was provided by two types of Earth Observation satellites presented in the report, coupled with the interpretive power of Australia’s biggest super computer and “more than a decade of Government investment in operational ocean modelling”.
Thanks to Earth observation data
Acknowledgements and the glossary in CSIRO’s oceanographic reports to the ATSB tell the story of how Earth observation satellites have provided significant data used in oceanographic analysis.
Satellites that have provided information in the search for MH370 include:
- The Inmarsat communication satellites that gave us the hourly Burst Timing Offset and Burst Frequency Offset data, which, together, narrowed the search down from a large portion of the entire Indian Ocean to just a segment of the 7th arc
- The Airbus Pleiades 1A satellite that provided the visual imagery of objects which, if they were parts of the aircraft, constitute the latest and most precise clue we have
- NOAA and AVHRR Sea Surface Temperature imagery which provided details of ocean circulation, significantly augmenting what could be deduced from other oceanographic techniques. This is measured by the Advanced Very High Resolution Radiometer (AVHRR) sensor carried by the (US) National Oceanic and Atmospheric Administration (NOAA) Polar Operational Environmental Satellites (POES)
- Altimetry data from satellite missions operated by the respective space agencies: Jason-2 (NASA and CNES), CryoSat2 (ESA), AltiKa (CNES and ISRO). An altimeter is an instrument carried by an earth-observation satellite that measures two quantities extremely accurately – its position in space and the distance to the surface of the ocean directly below, to estimate sea surface height. Maps of sea surface height are key to estimating sea surface currents, just like winds can be inferred from maps of atmospheric pressure.
“If we find MH370, which we all hope to do, it will be thanks to all this satellite data, particularly the altimetry data,’’ Griffin says.
Read a summary of the various clues supporting the oceanography.