AWI Bathymetric Chart of the Weddell Sea, Antarctica (BCWS)

From data collected by RV Polarstern, and additional echosoundings provided by national hydrographic offices, research institutions and the International Hydrographic Organization (IHO) Digital Bathymetric Data Center, the 1:1,000,000 Bathymetric Chart of the Weddell Sea (AWl BCWS) series has been developed. The heterogeneity of bathymetric data and the lack of observations within ice-covered areas required the incorporation of supplementary geophysical and geographical information. A semi-automatic procedure was developed for terrain modeling and contouring. In coastal regions, adjacent sub-glacial information was included in order to model the bathymetry of the transition zone along the Antarctic ice edge. Six sheets of the AWl BCWS series in the scale of 1:1,000,000 covering the southern Weddell Sea from 66°S to 78°S and from 68°W to 0°E were recently completed and included in the 1997 GEneral Bathymetric Chart of the Oceans (GEBCO) Digital Atlas CD-ROM (http://www.gebco.net). On the basis of these six 1:1,000,000 AWl BCWS sheets, a generalized 1:3,000,000-scale bathymetric chart was compiled for the entire southern Weddell Sea.

AWI Bathymetric Chart of the Gakkel Ridge (AWI BCGR) (Scale 1:150,000)

The 1 : 1,500,000 AWI Bathymetric Chart of the Gakkel Ridge (AWI BCGR) has been developed from multibeam data measured during the Arctic Mid-Ocean Ridge Expedition in 2001 (AMORE 2001, ARK-XVII/2). This expedition was conducted to investigate the Gakkel Ridge in the Arctic Ocean and was carried out by the icebreaking research vessels RV Polarstern and USCGC Healy. Polarstern is equipped with the multibeam sonar system Hydrosweep DS-2, whereas Healy carries Seabeam 2112. During the expedition an area of 8890 km length and 18 - 46 km width, situated between 82°N/8°W and 87°N/75°E, was surveyed simultaneously by both vessels. Water depths ranged from 566 to 5673 meters. Dense sea ice cover derogated the sonar measurements and decreased data quality. Data errors were corrected in an extensive post-processing. The data of two different sonar systems had to be consolidated in order to derive a high resolution bathymetry of the Gakkel Ridge. Final result was a digital terrain model (DTM) with a grid spacing of 100 meters, which was utilized for generating the map series AWI Bathymetric Chart of the Gakkel Ridge, consisting of ten map sheets.