Advances in Meteorology (Jan 2011)

Blocking Detection Based on Synoptic Filters

  • Bernd Schalge,
  • Richard Blender,
  • Klaus Fraedrich

DOI
https://doi.org/10.1155/2011/717812
Journal volume & issue
Vol. 2011

Abstract

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The Tibaldi-Molteni blocking index is supplemented by additional filter criteria to eliminate cut-off lows and subsynoptic structures. We introduce three blocking filters and analyse their sensitivities: (i) a quantile filter requiring a minimum geopotential height anomaly to reject cut-off lows, (ii) an extent filter to extract scales above a minimum zonal width, and (iii) a persistence filter to extract events with a minimum duration. Practical filter application is analysed in two case studies and the blocking climatologies for the Northern and the Southern Hemisphere.