Where To Track the Sea Ice

The website seaiceportal.de makes an important contribution to YOPP by providing up-to-date information on Arctic and Antarctic sea-ice changes, including expert knowledge and a cartographic data archive with comprehensive sea ice information.

Text: Malena Andernach and Kirstin Werner

With the aim to share scientific knowledge and data of sea-ice trends in the Arctic and Antarctic with all levels of society, the Helmholtz Climate Initiative (REKLIM), the Institute of Environmental Physics (IUP) at the University of Bremen and the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) launched the information and data portal seaiceportal.de (German version at meereisportal.de) in 2013. With its major influence on weather and climate in the polar regions and beyond, seaiceportal.de is of particular interest for the YOPP community.

The Importance of Sea Ice
The Arctic: A place characterized by cold with seemingly endless expanses of sea ice providing unique habitats to animals and plants. But such appearances are deceptive. Meanwhile, everyone have noticed that the Arctic is rapidly changing. On the contrary: since a first record-low of the sea ice extent in 2007 and an all-time low in 2012, news after news advise us on another year of Arctic minimum sea-ice extent. By the middle of this year, the Arctic sea ice has retreated to 1.91 million square kilometres below the 1981 to 2010 long-term average.

Seasonal variations as well as long-term changes of sea ice affect the weather and climate of the polar regions but also have global impacts. As it drives the thermohaline circulation of the Earth and thus the global climate, good knowledge on sea ice is indispensable for climate predictions in mid and lower latitudes but also significantly contribute to improved weather predictions in polar regions, as provided by YOPP.

Questions on Sea Ice and Ice Modelling
Coordinated by AWI colleagues Dr. Klaus Grosfeld and Dr. Renate Treffeisen, the website seaiceportal.de provides background information on, e.g. the global relevance of sea ice, its trends and fluctuations, interactions with other components of the climatic system as well as on sea ice as a habitat. – What sea ice is exactly? When does it form? And how does the freezing process actually take place? The website provides answers to these and further questions.

In addition, users can also learn about sea ice modelling. Numerical models are used by climate scientists to simulate the changes in sea-ice extent. The models represent the real physical processes in the form of mathematical basic equations and approximation formulas (so-called parametrizations). This allows researchers to reconstruct past presence of sea ice and to make future scenarios. Moreover, sea ice modelling is crucial for the description of the fundamental interactions of sea ice within the Earth’s climate system. Whereas, sea ice played only a subordinate role in the widely used General Circulation Models (GCMs) or Earth System Models (ESMs), it is increasingly represented now in newer global models. However, most of the climate models still tend to underestimate the decline in Arctic sea ice. Why? seaiceportal.de also has an explanation to this question.

How to Measure Sea Ice?
seaiceportal.de also delivers insights into the main monitoring methods of the most important sea-ice variables which are sea ice cover, its thickness and the thickness of the overlying snow cover as well as sea ice drift. In the more than one-hundred year history of sea-ice monitoring, the techniques have advanced from single observations from ships and coastal stations to nowadays regular airborne measurements and remote sensing satellites scanning, the latter delivering widely reliable and comprehensive information on sea ice. However, also today, local field experiments such as ice core drilling and even diving under the ice are conducted to obtain sufficient reference material.

At seaiceportal.de, the observational data, e.g. of the monthly sea-ice extent mean and anomalies, are presented in a wide range of maps, charts, and animations. The original data on sea-ice concentration, extent, thickness, drift and on snow depth collected by the University of Bremen by means of several satellite and other sensors can be downloaded for free from the portal. Furthermore, the portal delivers information of buoys, or more generally speaking "ice tethered platforms" that perform autonomous measurements of physical properties of sea ice, snow, and the uppermost ocean are one of the main instruments to collect time-series data sets from the remote polar regions. It presents data, metadata, and results from buoys drifting on Arctic and Antarctic sea ice. Depending on the product, the selectable time period dates back until 2002 and the offered temporal resolution varies from daily to monthly.

Current Location and Daily Life Aboard Polarstern
Finally, seaiceportal.de delivers information and news on polar expeditions, for example of the German research vessel Polarstern. Website visitors can track its current positions on hourly updated maps. In addition, they can get interesting insights into the daily life on board a research icebreaker, e.g. how Christmas is celebrated at sea. During the upcoming Arctic ice drift MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate, see more information also at https://www.mosaic-expedition.org/) aboard Polarstern, seaiceportal.de will provide up-to-date maps about sea ice related information of the expedition as well as showing the current position of the vessel from its start on September 20, 2019 when the research vessel will depart from Tromsø, Norway to spend the next year drifting through the Arctic Ocean, trapped in sea ice. Find more here: www.seaiceportal.de/mosaic

Contact: Renate Treffeisen renate.treffeisen@awi.de