New view of Arctic cyclone activity from the Arctic system reanalysis

Abstract

Arctic cyclone activity is analyzed in 11 year (2000-2010), 3-hourly output from the Arctic System Reanalysis (ASR) interim version. Compared to the global modern era reanalyses (European Centre for Medium-Range Weather Forecasts Reanalysis (ERA)-Interim, Modern Era Retrospective Analysis for Research and Applications, and National Centers for Environmental Prediction-Climate Forecast System Reanalysis), ASR shows a considerably higher number of cyclones over the Arctic with the largest differences over the high-latitude continental areas (up to 40% in summer and 30% in winter). Over the Arctic Ocean during both seasons ASR captures well the cyclone maximum in the Eastern Arctic which has 30% less cyclones in summer and is hardly detectable in winter in ERA-Interim. High resolution of the ASR model coupled with more comprehensive data assimilation allows for more accurate (compared to the global reanalyses) description of the life cycle of the most intense Arctic cyclones, for which ASR shows lower central pressure (4 hPa on average), faster deepening, and stronger winds on average. Key Points ASR reproduce 35% cyclones more over the Arctic The most intense cyclones are deeper and have stronger winds in ASR Maximum of cyclone counts in central Arctic exists both in summer and in winter ©2014. American Geophysical Union. All Rights Reserved.