IDS Workshop 
 
Venice 2006

IDS Workshop 2006Abstract

DORIS absolute velocities on Sorsdal and Lambert glaciers in Antarctica

Dr Jean-Jacques VALETTE(1), Dr Ramesh GOVIND(2), Dr Frank LEMOINE(3)

(1) Collecte Localisation Satellites, Ramonville-Saint-Agne, France
(2) Geoscience Australia, Camberra, Australia
(3) NASA Goddard Space Flight Center, Greenbelt, Maryland, US

Session theme: Stations coordinates

Abstract

As part of a Pilot Experiment of the International Doris Service (IDS), Geoscience Australia deployed DORIS beacons on the Sorsdal and Lambert glaciers near the Antarctic station of Davis. The Lambert-Amery system is the largest glacier-ice shelf system that contributes to the ice drainage in the East part of Antarctica. The monitoring of the ice sheet discharges in Antarctica or Greenland is of great importance as they impact the global mean sea level variation and the climatic change. The IDS campaigns of one or two months were carried out during the austral summers between 2001 and 2004 in order to test the system for the monitoring of ice movement. A DORIS beacon operates automatically and unattended which is a key asset for monitoring. Moreover, the data are stored by the instruments onboard the satellites and the data are downlinked and collected by SSALTO, the processing center in Toulouse, France, several times a day. The DORIS system geodetic capabilities for determining ITRF absolute positions are from a few cm within 48 cm using the MOE (Medium Orbit Ephemerides) up to a 1 cm when using the POE (Precise Orbit Ephemerides) or post-processing the orbit and station coordinates with refined models. Thus DORIS appears as a very appropriate tool to monitor ice surface displacements especially in a remote site lacking infrastructure such as in Antarctica ice sheet. This paper describes the campaigns that have been conducted at Sorsdal and Lambert glaciers and in particular the difficulties that have been faced due to the severe meteorological conditions. Each campaign where initially planned for a continuous one or month period. Practically this objective was not completely reached but enough data were collected for the estimation of absolute velocities of the DORIS antenna. Mean velocities have derived from multi satellite daily position estimates for the DORIS beacons. The measured ice drifts were mainly horizontal with amplitudes from around 10 cm/day (Sorsdal Dec. 2003- Jan. 2004) up to more than 1 m/day (Lambert Jan. 2003). For the first campaign which lasted 31 days, the DORIS mean ice-flow rate presents a good agreement with GPS measurements taken at the start and at the end of the campaign. The DORIS system is shown to be a reliable tool for continuous monitoring of glacial motion in Antarctica, Greenland…

 
Corresponding author:

    Dr Jean-Jacques VALETTE
    Collecte Localisation Satellites
    Parc Technologique du Canal
    8-10 rue Hermès

    31520 Ramonville St-Agne
    FRANCE
    Phone: +33 5 61 39 47 62
    Fax: +33 5 61 39 48 06
    E-mail:

 

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