A comparison of tracking methods for extreme cyclones in the Arctic basin

Abstract

A B S T R A C T Dramatic climate changes have occurred in recent decades over the Arctic region, and very noticeably in nearsurface warming and reductions in sea ice extent. In a climatological sense, Arctic cyclone behaviour is linked to the distributions of lower troposphere temperature and sea ice, and hence the monitoring of storms can be seen as an important component of the analysis of Arctic climate. The analysis of cyclone behaviour, however, is not without ambiguity, and different cyclone identification algorithms can lead to divergent conclusions. Here we analyse a subset of Arctic cyclones with 10 state-of-the-art cyclone identification schemes applied to the ERA-Interim reanalysis. The subset is comprised of the five most intense (defined in terms of central pressure) Arctic cyclones for each of the 12 calendar months over the 30-yr period from 1 January 1979 to 31 March 2009. There is a considerable difference between the central pressures diagnosed by the algorithms of typically 5Á10 hPa. By contrast, there is substantial agreement as to the location of the centre of these extreme storms. The cyclone tracking algorithms also display some differences in the evolution and life cycle of these storms, while overall finding them to be quite long-lived. For all but six of the 60 storms an intense tropopause polar vortex is identified within 555 km of the surface system. The results presented here highlight some significant differences between the outputs of the algorithms, and hence point to the value using multiple identification schemes in the study of cyclone behaviour. Overall, however, the algorithms reached a very robust consensus on most aspects of the behaviour of these very extreme cyclones in the Arctic basin.

Seasonal differences in the response of Arctic cyclones to climate change in CESM1

“…To measure trends in maximum cyclone intensity, these studies have largely focussed on minimum mean sea level pressure (MSLP), and studies generally agree that there is a general reduction in this quantity. A recent intercomparison of cyclone tracking methods by Simmonds and Rudeva (2014) concluded that different methods generally agree on which Arctic cyclones are most intense over the ERA-Interim reanalysis period . However, Chang (2014) cautions that differences in the definitions used in cyclone identification algorithms can lead to differing conclusions when investigating the response of strong cyclones to climate change.…”

Impact of radiosonde observations on forecasting summertime Arctic cyclone formation

“…The upper tropospheric trough is the TPV originating upstream at Svalbard [ Simmonds and Rudeva , ]. AC12 then absorbed the other surface cyclone and in the mature stage, and the cyclone's structure became equivalent barotropic with the TPV as it traversed the Arctic Ocean: This is indicative of the vertical vortex coupling mechanism proposed by Aizawa et al [] and Simmonds and Rudeva [], which can lead to rapid intensification of Arctic cyclones. However, clarifying this mechanism is beyond the scope of this paper, since we focus on the formation of AC12 prior to the rapid intensification.…”

Extreme Arctic cyclone in August 2016

“…Recently, Crawford and Serreze () indicated that the baroclinicity affected only on an intensification of ACs. The coupling with lower and upper cyclones was also important for the development of ACs (Simmonds and Rudeva, , ).…”