,There are basically three satellite methods that can be used to determine the mass balance of an ice cap, which is a huge glacier that covers the entire continent“, details with AFP Gerhard Kriner, Director of CNRS Research at the Institute of Environmental Geology (IGE). The one used by Jay Zwally’s team for a 2015 article is called altimetry. ,A satellite passes over the ice cap, sending out a laser beam, which is then transmitted back to the satellite. We measure the time it takes to go back and forth to measure the difference in height“, summarizes Gerhard Kriner to AFP on 12 August.
,Radar altimetry technology developed and adapted for flat sea surfaces, where it works very well“, tells Eric Rignot, professor at the University of California at Irvine and a NASA-affiliated researcher. ,On the ice cap, it is much less clear: it does not work in steep areas, including the Antarctic Peninsula, the coastal areas of Antarctica …“, he explains, also assuming that the errors related to the inaccuracy of the measurements thus far could have been made in the 2015 article, which was also based on data from satellites whose accuracy could have been improved from.
,The problem with elevation is that you can see the surface of the snow, but you can’t see where the snow begins, and you have to use modeling to figure out how the snowpack has changed. We measure the mass balance of an ice cap in kilograms, so we have to transfer the height to kilograms, and for that we have to make assumptions about the change in the density of the snowpack, which can be a hundred meters.“, Gerhard Kriner also abound.
,Compaction modeling is too difficult, the margin of error is too large“, says Eric Rignot. He believes “In his studies, Zwali improved his hat“which are not confirmed by measurements made using other methods.”A result is accepted when it has been independently verified dozens of times. In the case of this study, it remains an enigma of the outcome for many.“, he spoke with AFP on 12 August.
Amateur web specialist. General food junkie. Typical zombie enthusiast. Avid music trailblazer. Lifelong explorer.