Meteorology and oceanography of the Atlantic sector of the Southern Ocean—a review of German achievements from the last decade

Abstract

German universities and the AWI as well as other institutes involved in polar research. Here, we review the main findings in meteorology and oceanography of the last decade, funded by the priority program. The paper presents field observations and modelling efforts, extending from the stratosphere to the deep ocean. The research spans a large range of temporal and spatial scales, including the interaction of both climate components. In particular, radiative processes, the interaction of the changing ozone layer with large-scale atmospheric circulations, and changes in the sea ice cover are discussed. Climate and weather forecast models provide an insight into the water cycle and the climate change signals associated with synoptic cyclones. Investigations of the atmospheric boundary layer focus on the interaction between atmosphere, sea ice and ocean in the vicinity of polynyas and leads. The chapters dedicated to polar oceanography review the interaction between the ocean and ice shelves with regard to the freshwater input and discuss the changes in water mass characteristics, ventilation and formation rates, crucial for the deepest limb of the global, climate-relevant meridional overturning circulation. They also highlight the associated storage of anthropogenic carbon as well as the cycling of carbon, nutrients and trace metals in the ocean with special emphasis on the Weddell Sea.

The Weddell Gyre, Southern Ocean: Present Knowledge and Future Challenges

“…(2) The combination of physical and biogeochemical processes in the WG influences the world's oceans through the formation of water masses that spread north, well beyond the equator. (3) The distributions of macronutrients, micronutrients, and tracers with no active role in biogeochemistry are closely linked in this region (Hellmer et al, ).…”

“…Certain lines, for example, the one along the Prime Meridian, that have been sampled since the 1980s should be sampled at intervals pertinent to the scales of critical atmospheric and oceanographic processes. Long‐term changes, trends, or variability will thus become visible (Fahrbach et al, ; Hellmer et al, ; van Heuven et al, ). With a similar purpose, a Weddell observatory would be most useful in order to obtain time series in locations identified as characteristic of the gyre or where critical processes are more pronounced, for example, hot spots (e.g., http://www.soos.aq).…”

“…Black stippled lines mark two repeat sections along the Prime Meridian and across the Weddell Sea. (Hellmer et al, , Open Access).…”

“…In recent years, several review papers of the present and future Antarctic climate have been published (e.g., Hellmer et al, ; Mayewski et al, ; Turner et al, ). Against this background of climate change and variability, we introduce challenges for research specific to the WG.…”

Last Millennium volcanism impact on the South Atlantic Ocean

“…According to Núñez-Riboni and Fahrbach (2009), this current flows westward over the shelf acting as a dynamic barrier to the Warm Deep Water (WDW) and it is associated with shelf break fronts, as the Antarctic Shelf Front (Talley et al, 2011). For more details about the Weddell Sea, the reader is referred to Hellmer et al (2016).…”