31 ground-penetrating radar lines of Area 3 - Beach ridge plain (high wave energy) from Maxwell Bay, King George Island, Antarctic Peninsula

During a field campaign in the Austral spring 2012 the sedimentary architecture of a polar gravel-beach system at the southern coast of Potter Peninsula (Area 3) was revealed using ground-penetrating radar (GPR, Geophysical Survey Systems, Inc. SIR-3000). 31 profiles were collected using a mono-static 200 MHz antenna operated in common offset mode. Trace increment was set to 0.05 m. A differential global-positioning system (dGPS, Leica GS09) was used to obtain topographical information along the GPR lines. GPR data are provided in RADAN-Format, dGPS coordinates are provided in ascii format; projection is UTM (WGS 84, zone 21S).

Physical oceanography and ADCP measurements during METEOR cruise M71/3

Work on M71-3 aimed to answer the question whether phosphate loss and incomplete utilisation of nitrate on the one hand, or dinitrogen fixation on the other hand are responsible for unusual nutrient ratios in the water column of the eastern Mediterranean Sea. We investigated the reason for unusually depleted 15N/14N ratios in dissolved nitrate, suspended matter and surface sediments of that oligotrohic ocean basin. During a total of 18 days of ship time on R/V METEOR, Leg 3 OF M71 performed water column and surface sediment work in the eastern Mediterranean Sea (Heraklion-Istanbul). Stations will be aligned on one E-W and two N-S transects and sampled all major basins and water masses. On stations, CTD casts were obtained and water samples for nutrient concentrations were taken. These samples and those of suspended matter and surface sediment will be analysed for the stable nitrogen isotope composition of dissolved nitrate, suspended matter, and surface sediments. In addition, phytoplankton samples were be taken and experiments were be carried out to determine N2 fixation rates, genetic expressions of nitrogen fixation, and the composition of microbial and algal assemblages. One mooring of sediment traps (Ierapetra Deep) was be deployed and will be recovered in September 2007 to monitor changes in particle flux and its isotope signature over a seasonal cycle.

Transient Holocene experiments under orbital forcing using the comprehensive global climate model CCSM3 (Community Climate System Model 3)

The Southern Hemisphere Westerly Winds (SWW) have been suggested to exert a critical influence on global climate through wind-driven upwelling of deep water in the Southern Ocean and the potentially resulting atmospheric CO2 variations. The investigation of the temporal and spatial evolution of the SWW along with forcings and feedbacks remains a significant challenge in climate research. In this study, the evolution of the SWW under orbital forcing from the early Holocene (9 kyr BP) to pre-industrial modern times is examined with transient experiments using the comprehensive coupled global climate model CCSM3. Analyses of the model results suggest that the annual and seasonal mean SWW were subject to an overall strengthening and poleward shifting trend during the course of the early-to-late Holocene under the influence of orbital forcing, except for the austral spring season, where the SWW exhibited an opposite trend of shifting towards the equator.