The Sea Ice Thickness in the Atlantic Sector of the Southern Ocean

• Main Authors: Fahrbach, Eberhard, Behrendt, Axel
• Format: Conference Object
• Language: unknown
• Published: 2010
• Subjects: Antarc*; Antarctic; Sea ice; Southern Ocean
• Online Access: https://epic.awi.de/id/eprint/23120/; https://hdl.handle.net/10013/epic.35902

Sea ice covers millions of square kilometers of the Earths ocean surface. Therefore it significantly regulates the surface fluxes of water, heat and momentum between the ocean and the atmosphere. Moreover, sea ice is important for the climate on Earth because: It hampers gas exchange between ocean and atmosphere, it reflects a large portion of sunlight and itcontributes to the formation of deep and bottom waters which are part of the global ocean circulation. Examining the changes of sea ice has thus become an important field in Earth System Science.Thickness and extent are the two main characteristics of a sea ice cover and are important indicators of climatic changes. Sea ice extent is measured with microwave sensors from satellites since 1979 and shows a large-scale retreat of Arctic sea ice. Also the ice thickness in the Arctic reduced, as shown by upward sonar measurements from submarines since 1953. With the rapid decline of Arctic sea ice, also the Antarctic sea ice cover has attracted morescientific interest. The extent of Antarctic sea ice shows a small but significant positive trend for the period since satellite measurements began. But contrary to the Arctic, our knowledge about the long-term development of Southern Ocean sea ice thickness is still very limited. There are two main reasons for this lack of information: (1) The thickness of sea ice is still not routinely measured from space with sufficient accuracy and (2) there are no submarinemeasurements of ice draft for the Antarctic. But various airborne and in-situ techniques -like electromagnetic induction sounding, laser altimetry, ship-based observations and drilling - have been successfully applied in different regions of the Southern Ocean. However, the data gained by these methods are often biased towards thin ice and provide only shortsnapshots of the ice thickness.To date, the only way of monitoring the long-term variations of the sea ice thickness in the Southern Ocean are moored upward looking sonars (ULSs). These instruments are ...