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Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of twentieth century reanalysis

Applies an objective cyclone tracking algorithm to twentieth century reanalysis (20CR) 6-hourly mean sea level pressure fields for the period 1871–2010 to infer historical trends and variability in extra-tropical cyclone activity
Applies the tracking algorithm both to the ensemble-mean analyses and to each of the 56 ensemble members individually
Finds the ensemble-mean analyses are unsuitable for accurately determining cyclone statistics
Finds pooled cyclone statistics obtained by averaging statistics from individual members generally agree well with statistics from the NCEP-NCAR reanalyses for 1951–2010
Finds both reanalyses show similar cyclone trend patterns in the northern hemisphere (NH) over 1951–2010
Analyzes homogenized pooled cyclone statistics for trends and variability