Research

Aim: Assess the role of northern high-latitude ocean temperature anomalies in local climate feedbacks and large-scale atmospheric variability and predictability

Methods: Statistical analysis and physical interpretation of selected oceanic observations, atmospheric reanalyses data and numerical model outputs

Main results:

There is a growing evidence that Arctic sea ice anomalies influence mid-latitude weather and climate through coupled changes in the polar jet stream, planetary waves and storm tracks. In particular, the wintertime atmospheric conditions over Eurasia are sensitive to disturbances of sea ice cover in the Barents Sea.

Our previous studies, based on a lagged regression analysis between oceanic observations and atmospheric (NCEP/NCAR) reanalysis data in the period 1982–2006, indicate that more than 70% of the interannual variance of the total wintertime sea ice area in the Nordic (Greenland-Iceland-Norwegian and Barents) seas region can be explained by Atlantic water temperature (AWT) anomalies at the entrance to the Barents Sea in the preceding summer.
Click here hand dx.doi.org/10.1029/2010GL045894 and here hand ClimDyn.pdf for more details. These summertime AWT anomalies do strongly depend on local air-sea interactions in the Nordic seas region during the preceding winter.
Click here hand dx.doi.org/10.1029/2009JC005944 and here hand ClimDyn.pdf for more details.

When brought to the surface, oceanic heat anomalies influence not only the sea ice cover in the Nordic seas but also the local atmospheric conditions up to the tropopause level.
Click here hand dx.doi.org/10.1175/JCLI-D-13-00763.1 and here hand ClimDyn.pdf for more details. The sea ice and atmospheric anomalies persist in winter because of a feedback between oceanically-driven wind anomalies and wind-driven AWT anomalies.
Click here hand dx.doi.org/10.1175/JCLI-D-11-00594.1 and here hand ClimDyn.pdf for more details.

A question is whether remote effects of sea ice anomalies in the Nordic seas are modulated by interannual variability in oceanic forcing. Preliminary results, based on a statistical analysis of the observed ocean temperature at the entrance to the Barents Sea and the atmospheric (NCEP/NCAR reanalysis) fields in the 1982–2006 period, show that the summertime AWT anomalies are indeed significant precursors of a large-scale wintertime atmospheric variability. In particular, positive AWT anomalies precede a ‘warm Arctic-cold Eurasia’ pattern of surface air temperature anomalies. An Eulerian analysis of synoptic atmospheric variability indicates that the teleconnections of the wintertime climate in middle latitudes to the high-latitude AWT variability may result from a reorganization of storm tracks.
Click here hand dx.doi.org/10.1007/s00382-015-2930-5 and here hand ClimDyn.pdf for more details.


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