Proposed CMIP Sub-Project :

Arctic Climate, Atmospheric Circulation And Ocean Warming

Leonid P.Bobylev¹, Svetlana I. Kuzmina¹,^.Genrikh V.Alekseev², Ola M. Johannessen³, Lennart Bengtsson⁴

¹Nansen International Environmental and Remote Sensing Center, St. Petersburg, 197061, Russia,

²Arctic and Antarctic Research Institute, St. Petersburg, 199397, Russia.

³Nansen Environmental and Remote Sensing Center, Bergen, 5059, Norway,

⁴Max Planck Institute for Meteorology, Hamburg, 20146, Germany,

svetlana.kuzmina@niersc.spb.ru

Background.

Recent modeling studies indicated that greenhouse global warming should be enhanced in the Arctic. An enhanced Arctic response is seen in general circulation models for different sorts of external forcing such as changes in solar irradiation and changes in the concentration of greenhouse gases. Modeling results demonstrated that there was a connection between tropical sea surface temperature anomalies, intensification of mid-latitude westerlies (e.g. North Atlantic Oscillation (NAO)) and Arctic surface temperature anomalies. Another intriguing observation is the lack of correlation or rather negative correlation between NAO and Arctic SAT 1890-1950. Observations suggest that Arctic Oscillation, and the more spatially confined NAO, have exhibited a positive trend since the early 1980s and it is speculated that this may be related to global warming. At the same time in many previous and recent works it was shown that recent climate change could be interpreted in terms of changes in the frequency of occurrence of natural atmospheric circulation regimes. The extent to which forced climate change pattern and the unforced modes of variation are determined by the same mechanisms and feedbacks remains to be determined.

The main objective is to assess atmospheric circulation modes and related climate variations in the Arctic and sub-Arctic over natural and anthropogenic forcing.

Content of study

• Analysis of results of coupled global and regional GCMs together with observational data in order to estimate the climate variation modes and related temperature changes in the Arctic and sub-Arctic.
• Quantitative assessment of the variations of the sea ice parameters related to the changes in the atmospheric thermal and circulation regimes.
• Assessment of natural and anthropogenic components in previous and future climate changes in the Arctic.

Research will be focused on:

Analysis of the performance of the CMIP2 runs in order to :

· Explore the large scale processes behind an Arctic warming , the relation between NAO in the models and the Arctic warming.

· Determine model teleconnections between climate change in the Arctic, mid- and low latitudes, and the role of the tropical oceans in a warming in the Arctic.

· Evaluate different mechanisms which could be responsible for the 1930s and latest warming in the Arctic.

The minimum data fields we need to have for a study of this type (in addition to surface temperature, pressure and precipitation) are sea ice (coverage and volume), 850, 500 and 200 height fields.