%0 Journal Article
%T Blocking Detection Based on Synoptic Filters
%A Bernd Schalge
%A Richard Blender
%A Klaus Fraedrich
%J Advances in Meteorology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/717812
%X 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.
%U http://www.hindawi.com/journals/amet/2011/717812/