An Automated Classification of Pressure Patterns over the British Isles

The aim of this work is to introduce an automated classification scheme for atmospheric pressure which can be applied over the British Isles. There are two well-known correlation-based objective or automated weather-typing schemes - the Lund and Kirchhofer methods - which could be used for an objective classification of British pressure patterns. The Kirchhofer method has been accepted here as the most suitable in the search for an atmospheric classification technique. Seven different threshold values for the Kirchhofer method are discussed and that proposed by Barry taken as the most appropriate. This threshold is used to develop a pressure-pattern catalogue based on mean sea-level pressure (MSLP) data around the British Isles. This attempt at objectively classifying MSLP is one of the first applications of such a method to the area of the British Isles. The daily mean sea-level pressure data is categorized into fifteen pressure patterns from a ten-year daily sample (1977-86) and the results discussed.