Arctic Maritime Cyclone Distribution and Trends in the ERA5 Reanalysis

Abstract

We present a tracking algorithm for synoptic to meso-α-scale Arctic cyclones that differentiates between cold- and warm-core systems. The algorithm is applied to the ERA5 reanalysis north of 60°N from 1950 to 2019. In this dataset, over one-half of the cyclones that meet minimum intensity and duration thresholds can be classified as cold-core systems. Systems that undergo transition, typically from cold to warm core, make up 27.2% of cyclones and are longer lived. The relatively infrequent warm-core cyclones are more intense and are most common in winter. The Arctic-wide occurrence of maritime cyclones has increased from 1979 to 2019 when compared with the period from 1950 to 1978, but the trends have high interannual variability. This shift has ramifications for transportation, fisheries, and extractive industries, as well as impacts on communities across the Arctic.