Polar low climatology over the Nordic and Barents seas based on satellite passive microwave data

Abstract

A new climatology of polar lows over the Nordic and Barents seas for 14 seasons (1995/1996–2008/2009) is presented. For the first time in climatological studies of polar lows an approach based on satellite passive microwave data was adopted for polar low identification. A total of 637 polar lows were found in 14 extended winter seasons by combining total atmospheric water vapor content and sea surface wind speed fields retrieved from Special Sensor Microwave/Imager data. As derived, the polar low activity in the Norwegian and Barents Seas is found to be almost equal, and the main polar low genesis area is located northeastward of the North Cape. For the Barents Sea, a significant correlation is found between the number of polar lows and mean sea ice extent. Individual indicative polar low characteristics (i.e., diameter, lifetime, distance traveled, translation speed, and maximum wind speed) are also presented.

A simplified wave enhancement criterion for moving extreme events

“…In particular, estimated nondimensional fetch close to or larger than the critical value will indicate that the resonance effect will be large with a rightward wave energy marked enhancement. The criterion can further be used for future investigations concerned with TC-induced vertical mixing [e.g., Grodsky et al, 2012], climatology completeness [e.g., Knaff et al, 2013;Smirnova et al, 2015], radiating swell determination and dissipation estimation [e.g., Ardhuin et al, 2009;, but also investigations concerned by the local sea state impact on microwave measurements to infer surface extreme wind speeds from passive instruments [Uhlhorn and Black, 2003;Reul et al, 2012;Zabolotskikh et al, 2013Zabolotskikh et al, , 2015 and future bistatic L-band Cyclone Global Navigation Satellite System (i.e., CYGNSS [Ruf et al, 2013]).…”

An objective global climatology of polar lows based on reanalysis data

“…For the same region, and for the years 2000-2012, Noer et al (2011 developed the Sea Surface Temperature and Altimeter Synergy for Improved Forecasting of Polar Lows (STARS) database. Recently Smirnova et al (2015) proposed a new PL climatology of this region based on satellite passive microwave data for 1995-2009 and referred to here as the Smirnova database. This database includes considerably more cases than does the STARS database.…”

Re‐examining the roles of surface heat flux and latent heat release in a “hurricane‐like” polar low over the Barents Sea

“…The open waters of the Nordic Seas are one of the main breeding grounds of polar lows [Rasmussen and Turner, 2003], an intense subset of polar mesocyclones. Many polar lows form over the Barents Sea [Rasmussen, 1985;Wilhelmsen, 1985;Ese et al, 1988;Blechschmidt, 2008;Kolstad, 2015;Smirnova et al, 2015], which is largely ice-free even in the depth of winter.…”