Extra-tropical cyclone climatology and shifts in climate regime in the Northern Hemisphere ...

• Main Author: Grant, Andrew P.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Arctic
• Online Access: https://dx.doi.org/10.14288/1.0052401; https://doi.library.ubc.ca/10.14288/1.0052401

Extra-tropical cyclones are an important feature of mid-latitude weather and climate. The interdecadal variability of extra-tropical cyclones is assessed here. This is undertaken with respect to changes in Northern Hemisphere atmospheric circulation associated with a shift in climate regime around 1976/77. Data from the Goddard Institute of Space Studies (GISS) Atlas of Extra-tropical Cyclones and National Snow and Ice Data Centre (NSIDC) Arctic Cyclone Track Data Set are used to construct a climatology of cyclones and intense cyclones (those reaching a minimum sea level pressure less than 980hPa) in the Northern Hemisphere. Time series of cyclone data in various regions are analysed to assess relationships with indices representing the 1976/77 shift and changes in trend over the period investigated. The possibility of a second shift around 1989 is also investigated. Indices used are based on phases of the Pacific Decadal Oscillation (PDO). Emperical Orthogonal Function (EOF) analyses are also used to ...