OCTEL- Ocean sea-ice atmosphere teleconnections between the Southern Ocean and North Atlantic during the Holocene

Project Department: Uni Research Climate (group: Global climate systems, climate sensitivity and climate predictions) period: 01.04.16 - 31.12.20

About the project

The joint Indo-Norwegian research project OCTEL aims to explore the ocean, sea-ice and atmosphere interactions both in the Southern Ocean and the northern North Atlantic in order to assess the manifestation of interhemispheric teleconnections and their influence on climate during last 11 700 years (the Holocene) with a special focus on the last 2000 years.

The first object of the project is to improve our understanding about the sea surface temperature and sea-ice variability in the Southern Ocean and northern North Atlantic over the last 10 000 years. For this, we are now doing diatom analyses from marine sediment cores from the Southern Ocean and Svalbard, and generating quantitative reconstructions of sea surface temperature (SST) and sea-ice using statistical transfer function method.

We are proceeded well with the analyses from the marine sediment core taken from Conrad Rise, the Southern Ocean. Also the SST reconstruction for the last 4000 years is ready. The initial results indicate relatively stable ocean temperatures, but also several cooling events. It seems that the atmospheric patterns may have caused some of these cooling events, and also coldness across Antarctica at the same time. In the interhemispheric scale, it is possible that coldest event in our study area was caused by strengthened Atlantic circulation system.

In Svalbard, diatom analyses from two sediment cores taken from Kongsfjorden and Krossfjorden are in progress. Initial results from the first sediment core from Kongsfjorden represent the time interval 500-250 years before present. This time interval represents so called the Little Ice age, which was a cold climate period in the northern hemisphere. Our results show that the ocean was a bit colder and sea-ice conditions were severe than today, but sea-ice melted in summertime also during this cold climate period.

We continue analyses from the Southern Ocean and Svalbard. In the next stages, we will (2) analyse the relation of oceanic and atmospheric variability both in the southern and northern hemispheres, (3) assess the existence and magnitude of teleconnections between the Southern Ocean and the North Atlantic on different time-scales, (4) model the dynamics of the ocean-sea ice-atmosphere system and teleconnections in the Atlantic Ocean, (5) inform policy makers and the public of the project's results on the impact of regional climate changes to global climate change through teleconnections.

The project will contribute to increased knowledge on how the ocean?sea-ice?atmosphere systems of the Northern and Southern hemispheres are coupled together at different time-scales. This new knowledge will improve the global climate models and enable more precise climate projections for the future, which will be beneficial to society?s adaptation strategies.

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cp: 2019-12-04 11:17:03