Pack ice convergence measurements by GPS–ARGOS ice beacons

• Published in: Cold regions science and technology 1998-10, Vol.28 (2), p.59-72
• Main Authors: Prinsenberg, S.J, Fowler, G.A, van der Baaren, A
• Format: Article
• Language: English
• Subjects: Convergence measurements; Earth, ocean, space; Exact sciences and technology; External geophysics; GPS–ARGOS ice beacons; Pack ice; Physics of the oceans; Sea ice
• ISSN: 0165-232X; 1872-7441
• DOI: 10.1016/S0165-232X(98)00013-5

Satellite-tracked ice beacons containing Global Position System (GPS) location sensors were field tested for their reliability and their position accuracy (both relative and absolute) before being deployed on the mobile pack ice to monitor pack ice motion. On flat lake ice, a single beacon on average provided hourly data 87% of the time with a position accuracy of 20 m. In ice rubble, data availability was reduced to 83% and position accuracy decreased to 35 m. Between pairs of beacons, relative distance accuracy depended on whether the positions of the beacons were derived using the same satellite constellation. For all available position data, the data availability for relative distances between beacons was 78% for the short 1-day data set of the lake ice site and 69% for the longer 25-day data set of the ice rubble site. Relative distance accuracies were respectively 15 and 20 m using all position data. When positions were derived using the same satellite constellation for beacon pairs, the data availability reduced to 60% for the lake site and 52% for the ice rubble site while the relative accuracy increased respectively to 1.5 m (lake) and 10 m (ice rubble). The beacons proved their durability by monitoring the ice motion for an additional 60 days in an offshore experiment in which three floes forming a triangle were tracked until the floes the beacons were on melted.