| Title | Determination of sea ice surface elevation with laser and radar altimetry and comparison with ice thickness data sets in the Arctic and Antarctic |
| Author | Göbell, S. |
| Author Affil | Göbell, S., Alfred-Wegener- Institut für Polar- und Meeresforschung, Potsdam, Federal Republic of Germany |
| Source | Berichte zur Polar- und Meeresforschung = Reports on Polar and Marine Research, Vol.559, 161p. . Publisher: Alfred- Wegener-Institut für Polar- und Meeresforschung, Bremerhaven, Federal Republic of Germany. ISSN: 1618- 3193 |
| Publication Date | 2007 |
| Notes | In English with German summary. Ph.D. thesis. 112 refs. GeoRef Acc. No: 283939. CRREL Acc. No: 62004368 |
| Index Terms | accuracy; aerial surveys; airborne radar; helicopters; ice; lasers; radar; remote sensing; snow; statistical analysis; thickness; Arctic Ocean; Baltic Sea--Gulf of Bothnia; Southern Ocean--Weddell Sea; airborne methods; altimetry; Atlantic Ocean; Baltic Sea; depth; elevation; errors; Global Positioning System; Gulf of Bothnia; helicopter methods; histograms; laser methods; North Atlantic; radar methods; satellite methods; sea ice; Southern Ocean; Weddell Sea |
| Abstract | The knowledge of sea ice thickness plays a critical role in the discussion of global climate change related issues. Up to now, satellite missions have been used to map the extent of sea ice but it has been impossible to measure its thickness directly. Recent and upcoming satellite missions such as ICESat and CryoSat-2 measure the surface elevation, and freeboard respectively of sea ice which can be transformed to total thickness. In this study, surface elevation is defined as the height of the snow surface and freeboard as the height of the ice surface above local sea level throughout the ice floe. Measurements of surface elevation have been performed by means of laser altimetry and differential GPS (DGPS) using a helicopter suspended sensor. Surface elevation is derived from the difference between the laser range measurement above the snow surface and the instrument's height above the geoid determined by DGPS (GPS height) yielding the geolocated elevation above the geoid (ground elevation). Ground elevation is different from surface elevation because the local sea level deviates from the geoid which is used as reference for the GPS height due to geoid errors and the unknown dynamic sea surface topography. Therefore, after the first processing, the ground elevation of open water sites between the ice floes is not zero. This bias can be removed by implementing a specific filtering operation. On average, the accuracy of the surface elevation is estimated as ± 0.1m. However, it can increase considerably depending on the roll angle of the sensor. Results of surface elevation are compared with coincident profiles of a laser scanner, in-situ measurements, and sea ice thickness measured in the Lincoln Sea in the Arctic and in the Weddell Sea in the Antarctic. (mod. auth. abst.) |
| URL | http://hdl.handle.net/10013/epic.26866.d001 |
| Publication Type | monograph |
| Record ID | 83937 |