Group seminar on 6. July, 14:15 CET

Trend analysis of North Atlantic and North Pacific cyclones in long-term ERA5 data series

Alexia Karwat

Extratropical cyclones are the primary natural hazard affecting the mid-latitudes. With the release of ERA5 reanalysis data from 1950-1978 by the European Centre for Medium-Range Weather Forecasts (ECMWF), new opportunities have arisen to investigate trends of mid-latitude cyclones in longer and higher resolution. Here, we use quantile regression (e.g. Koenker and Hallock 2001) to identify trends and quantify the results using the modified Mann-Kendall trend test (Hamed and Rao 1998).

Our results suggest a significant increase in the intensity of North Atlantic cylones in 1950-2019. Additionally, we show a significant northward shift of the North Atlantic cyclone track. In contrast, the number of North Pacific cyclones is significantly increasing; these storms show longer life cycles and travel longer distances, while they also grow more slowly in 1950-2019. Moreover, the trend analysis suggests a significant decrease in cyclone-related precipitation. In addition, our results indicate an overall increase in Northern Hemisphere storminess.