|The Roi Baudouin Ice shelf and the position of the Tweeting Ice Shelf components (arrow)|
We therefore installed three GPS systems, one inside the depression and two on the flanks. The ones on the flanks are simple GPS systems that record there position every hour and transmit these data over satellite phone twice a day. They are called GPS CGEO (from Cercle de Géographie et de Géologie de l'ULB) and GPS CDS (from Cercle des Sciences). The Cercle des Sciences co-sponsored the project.
|GPS CGEO and CDS prior to installment|
Besides these GPS we also burried a radar system in the center of the channel, which is as well equipped with a GPS. That system - a phase-sensitive radar acquired on a FNRS project - enables to monitor on a hourly basis the internal structure of the ice shelf. A radar signal is transmitted through the ice and reflects off the contact with the ocean. The second antenna receives the reflected signal that has been attenuated while going through ice impurities and denser layers of ice. The phase sensitive radar (or pRES) is capable of detecting changes in the position of these layers. So, we will be capable of measuring the internal flow of the ice shelf. But we will also be capable detecting changes at the contact with the ice shelf, whether there is melting, how much and when precisely.
|Installation of the pRES radar in the snow. The whole system is buried under the snow surface.|
|Happy that the job is done!|