Climate Dynamics

, Volume 45, Issue 7, pp 2137–2150

Extreme small-scale wind episodes over the Barents Sea: When, where and why?

Article

DOI: 10.1007/s00382-014-2462-4

Cite this article as:
Kolstad, E.W. Clim Dyn (2015) 45: 2137. doi:10.1007/s00382-014-2462-4

Abstract

The Barents Sea is mostly ice-free during winter and therefore prone to severe weather associated with marine cold air outbreaks, such as polar lows. With the increasing marine activity in the region, it is important to study the climatology and variability of episodes with strong winds, as well as to understand their causes. Explosive marine cyclogenesis is usually caused by a combination of several mechanisms: upper-level forcing, stratospheric dry intrusions, latent heat release, surface energy fluxes, low-level baroclinicity. An additional factor that has been linked to extremely strong surface winds, is low static stability in the lower atmosphere, which allows for downward transfer of high-momentum air. Here the most extreme small-scale wind episodes in a high-resolution (5 km) 35-year hindcast were analyzed, and it was found that they were associated with unusually strong low-level baroclinicity and surface heat fluxes. And crucially, the 12 most severe episodes had stronger cold-air advection than 12 slightly less severe cases, suggesting that marine cold air outbreaks are the most important mechanism for extreme winds on small spatial scales over the Barents Sea. Because weather models are often unable to explicitly forecast small-scale developments in data-sparse regions such as the Barents Sea, these results can be used by forecasters as supplements to forecast model data.

Keywords

Polar lowsNumerical modelsExtreme weatherHindcasts

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.StormGeoBergenNorway
  2. 2.Uni Research and Bjerknes Centre for Climate ResearchBergenNorway