HR: 0800h
AN: C11B-0453    [Abstracts]
TI: A Study of Snow Thickness on First- and Multiyear Sea Ice Using Laser and Radar Altimetry
AU: * Hanson, S
EM: sha@space.dtu.dk
AF: Danich National Space Center, Juliane Maries Vej 30, Copenhagen OE, 2100, Denmark
AU: Stenseng, L
EM: stenseng@space.dtu.dk
AF: Danich National Space Center, Juliane Maries Vej 30, Copenhagen OE, 2100, Denmark
AU: Forsberg, R
EM: rf@space.dtu.dk
AF: Danich National Space Center, Juliane Maries Vej 30, Copenhagen OE, 2100, Denmark
AU: Hvidegaard, S M
EM: smh@spacee.dtu.dk
AF: Danich National Space Center, Juliane Maries Vej 30, Copenhagen OE, 2100, Denmark
AU: Skourup, H
EM: hsk@space.dtu.dk
AF: Danich National Space Center, Juliane Maries Vej 30, Copenhagen OE, 2100, Denmark
AB: Verifying the accurate thickness of sea ice is of major importance. The snow depth on sea ice is a dominating source of error when detecting the baseline thickness of the polar sea ice using airborne or satellite laser altimetry. By combining laser and radar altimetry new information is obtained and the boundary between the snow pack and the ice surface can be distinguished. This technique will be used on the CryoSat-2 mission, due for launch in 2009. In spring 2006 a major validation campaign of the CryoSat-2 was carried out in the Arctic Ocean North of Greenland and Canada. The aim was to validate the airborne radar and laser instrumentation planned for the CryoSat-2 mission. The radar ESA coherent radar ASIRAS with 13 GHz center frequency and 1 GHz band width resembling the radar on CryoSat-2. In situ snow depths, snow physics, sea ice thickness and freeboard were measured at two sites on the sea ice north of the Canadian Forces Station Alert, Ellesmere Island (82°30' N 62°19' W). Site 1 was on multiyear fast ice (MYI), approximately 5 km from the coast line. Site 2 was approximately 10 km north of Alert, on first-year ice (FYI). These two sites were marked with radar corner reflectors that ensure truly coincident observations. On FYI ASIRAS data show good agreement between in situ and airborne measured data. On MYI the layered snow pack generate uncertainties due to the complex return signal from ice layers of refrozen melt water within the snow pack. The MYI site poses several difficulties due to the disturbed ice field consisting of new ice, old porous ice, refrozen melt water and ridges. These disturbances generally raise the noise level and introduce false reflectors caused by ridges nearby.
DE: 0736 Snow (1827, 1863)
DE: 0750 Sea ice (4540)
DE: 0758 Remote sensing
SC: Cryosphere [C]
MN: 2007 Fall Meeting