ABSTRACTS

• Main Author: Frédérique Rémy
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland; Antarc*; Antarctica; Ice Sheet; Ice Shelves; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.571.7275; http://earth.esa.int/workshops/venice06/participants/1323/paper_1323_rmy.pdf

Altimetry is probably one of the most powerful tools for the observation of the sea ice and of ice sheets. In 15 years, our vision of these large ice masses has been deeply transformed. For sea ice, while a lot of sensors are able to measure the surface or the age, altimetric is a unique mean to measure the thickness. For ice sheet, the topography is one of the pertinent parameters related to the processes acting on ice sheet. Because it is a free surface, it description strongly helps in ice modelling. From the global scale to the km-scale, the topography hides the signature of the physical processes as well as the one of external forcing. Moreover, altimeter also provides other parameters such as backscatter and waveform shape that give information on the surface, roughness or snow pack characteristics. The altimetric series of ERS1, ERS2 and Envisat now provide 15 years of continuous and homogeneous observations. These long series allow noticing the sea ice thickness decreasing, the shape and volume changes of both ice sheets, Greenland and Antarctica, related to climate change and to carefully follow the component the most sensitive to climate change such as the ice shelves. Thanks to the launch of Envisat, for the first time a dual-frequency observation is possible, allowing a better understand of the physics of the measurements.