Meteorology and Atmospheric Physics

, Volume 116, Issue 1–2, pp 27–42

The bimodal downslope windstorms at Kvísker

Original Paper

Abstract

Downslope windstorms at Kvísker in Southeast Iceland are explored using a mesoscale model, observations and numerical analysis of the atmosphere. Two different types of gravity-wave induced windstorms are identified. At the surface, their main difference is in the horizontal extent of the lee-side accelerated flow. Type S (Short) is a westerly windstorm, which is confined to the lee-slopes of Mount Öræfajökull, while a Type E (Extended) windstorm occurs in the northerly flow and is not confined to the lee-slopes but continues some distance downstream of the mountain. The Type S windstorm may be characterized as a more pure gravity-wave generated windstorm than the Type E windstorm which bears a greater resemblance to local flow acceleration described by hydraulic theory. The low-level flow in the Type E windstorm is of arctic origin and close to neutral with an inversion well above the mountain top level. At middle tropospheric levels there is a reverse vertical windshear. The Type S windstorm occurs in airmasses of southerly origin. It also has a well-mixed, but a shallower boundary-layer than the Type E windstorms. Aloft, the winds increase with height and there is an amplified gravity wave. Climate projections indicate a possible decrease in windstorm frequency up to the year 2050.

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Institute for Meteorological ResearchReykjavíkIceland
  2. 2.University of IcelandReykjavíkIceland
  3. 3.Icelandic Meteorological OfficeReykjavíkIceland
  4. 4.Bergen School of Meteorology, Geophysical InstituteUniversity of BergenBergenNorway

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