Dates and Positions of Polar lows over the Nordic Seas between 2000 and 2010

Transcription

1 no. 16/2010 Polar Lows Dates and Positions of Polar lows over the Nordic Seas between 2000 and 2010 Gunnar Noer and Trond Lien

2 report Title Dates and positions of polar lows over the Nordic Seas between 2000 and 2010 Section Oceanography Author(s) Gunnar noer and Trond Lien Client(s) Date Report no. No. 16/2010 Classification Free Restricted ISSN e-issn Client s reference Abstract Based on NOAA AVHRR, synoptic observations and daily registrations at the Norwegian Meteorological Institute (met.no) in Tromsø. Focus of registrations are mainly from the Greenland east coast to Novaya Zemlja, and from 65N the arctic ice edge. The list contains most, but not all, of the polar lows in this area. The selection of the polar lows are based on the definition of the European Polar Low Working Group (EPLWG): A small but fairly intense low in cold air outbreaks well north of the polar front, with a cyclonic cloud structure and a diameter of km. Wind data is taken from synoptic observations of past max 10 minute 10m wind, or from Qscat/Ascat. When synoptic observations are not available, the low is identified from visual appearance. The cases marked by ** are added on a recent revision from visual inspection of NOAA AVHRR channel 4 images stored at the met.no. Dates and positions refer to the time when the low is first identified as a fully developed polar low, i.e. early in the life span of the low. Minimum pressure and maximum wind is taken from analysis made at the Norwegian Meteorological Institute in Tromsoe, covering the entire lifespan of the low. The extreme values typically occur some 3 9 hrs after first identification. Because of the scarcity of observations, the pressure estimate is Keywords Polar lows, Nordic Seas Disiplinary signature Responsible signature

3 Date Time (utc) Lat. Long. Remark Min.SLP (hpa) N 18E ,5N 29E Old Erik N 04E Cirrus on top Max wind (kt) N 4E N 21E Most beautiful N 22E ** ,5N 03W Pre Mike N 01E The Mike Low N 41E ** N 08E ** ,5N 09E Marginal N 02E Baroclinic N 09W ** N 19E The Torsvåg case, Cirrus outflow N 02E ** N 25E ** ,5N 07E N 38E Dual ** N 21E N 47E N 28E Dual systems N 17E Multiple N 12E Most beautiful N 34E Most beautiful N 33E Dual ** ,5N 07E N 10E The polar storm ** N 05W ** N 1530E Dual systems N 47E Ivans low ** N 1100E N 38E Multiple ** N 0730E ,5N 25,5E Slow moving N 10E Multiple ** ,5N 0,5E Reversed shear N 05E ** N 16,5E ,5N 12,5E Comma in SW 45

4 ,5N 18E Reversed shear N 14E Reversed shear N 31E Reversed, secondary N 38E N 18E N 13E ** N 12E Widespr. conv., N 08W Short lived ** N 12E ** ,5N 03E Neutral (no) shear N 06,5E Direct shear, fast moving, dual N 05E ** N 09E ** N 00E Dual, neutral, secondary N 15E Reversed, secondary G N 37E Reversed N 45E Dual ** ,5N 46E Small ** N 04W Secondary, direct shear N 06E Secondary, reversed, Radar, Soundings N 07E Primary, neutral, poor models N 03W Large system ** N 13E N 37E ** N 35E ** N 18E The Brümmer case N 04E Direct, primary N 48E Direct/neutral N 2430E Secondary, strong reversed N 25E Cirrus shield ** N 00E ** N 18E Double-system/Comma in SW N 04E Sounding LDWR, Radar Vest- Finnmark Small (130km) Hopen Shear vorticity (Bear Island-Spitsbergen) Lofoten - Vesterålen From a CB-cluster 30G N 00E Multiple, widespread conv. JM sound N 16E Primary, good models G N 07W N 17E Secondary, baroclinic, poor mod G N 18-22E Secondary, inst. Occ., reversed G63 40

5 N 41E Primary, Stockman, widespread N 04E Primary, direct, widespread N 1430E Primary, cold, cirrus shield, case Vest- Finnmark Primary, cold, cirrus shield N 09E 2 small polar lows N 23E Small PL N 11E Strong PL, long life time, baroclinic Berlevåg- Vadsø Baroclinic PL N 07E Season start! N 31E N 08E Comma N 11E Primary N 38E Primary, Reversed? N 24 E Dual /69N 09/10E Dual, small N 03E The Thorpex Low N 12E Baroclinic N 2830E Dual, reversed N 43 E N 01E Primary, reversed N 41E N 04E Secondary, reversed, NE of Scotland N 25E N 02E N 14E Baroclinic, N 08E Secondary, reversed, good models N 00E Secondary, reversed, dual N 01W Convergence, baroclinic N 34E Marginal N 28E Multiple N 53E * N 57E Baroclinic, Kara Sea N 03W N 40E Small, dual N 43E Dual N 22E * N 13E Dual, reversed, Baroclinoc N 3230E Neutral, baroclinic N 07W N 3530E Baroclinic, reversed N 43E Baroclinic, reversed N 25E Cirrus waves on top!

6 N 1630E Small, N of Spitsbergen, conv N 08E In SE off Scandinavian mainland N 04E N 02E Convective, marginal N 04E No observations N 17W N 04E Small, dual, U~20, B, Neutral, Florø N 42E Small N 41E N 19E Multiple N 16E No observations N 18E Dual N 12E Short lifespan, Neutral, U~ N 18E Comma, later PL N 1930E Baroclinic, reversed, U~ N 02E Baroclinic, reversed N 1930E One fatality, baroclinic, neutral Acknowledgement We thank the forecasters on duty at the Norwegian Meteorological Institutes forecasting centre in Tromsø,, for a continued effort in the recording of these data.

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