Subantarctic cyclones identified by 14 tracking methods, and their role for moisture transports into the continent

Grieger, Jens; Leckebusch, Gregor C.; Raible, Christoph; Rudeva, Irina; Simmonds, Ian (2018). Subantarctic cyclones identified by 14 tracking methods, and their role for moisture transports into the continent. Tellus. Series A - dynamic meteorology and oceanography, 70(1), p. 1454808. Blackwell Munksgaard 10.1080/16000870.2018.1454808

[img]
Preview
Text
Subantarctic cyclones identified by 14 tracking methods and their role for moisture transports into the continent.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (3MB) | Preview

Extra-tropical cyclones in the subantarctic play a central role in the poleward transport of heat and moisture into Antarctica, with the latter being a key component of the mass balance of the Antarctic ice sheet. As the climate in this region undergoes substantial changes, it is anticipated that the character of these synoptic features will change. There are a number of different methods used to identify and track cyclones, which can potentially lead to different conclusions as to cyclone variability and trends, and mechanisms which drive these features. Given this, it is timely to assess the level of consensus among 14 state-of-the-art cyclone identification and tracking methods. We undertake this comparison with the ERA-Interim data-set for the period 1979–2008 and find large differences in the number of tracks identified by different methods, but the spatial patterns of the system density broadly agree. Links between large-scale modes of variability, such as the Southern Annular Mode (SAM), and subantarctic cyclones as suggested in the literature are confirmed by our analysis. Trends in the number of cyclone tracks show a more diverse picture. Robust trends are identified by almost all methods for austral summer over the region south to 60°S, mainly due to the strong relation to SAM, whereas in austral winter the methods disagree in the statistical significance of the trends. The agreement among the methods is greater when the comparison is confined to the stronger cyclones. This is confirmed by a moisture flux analysis associated with these strong synoptic systems. Our results indicate that multiple cyclone identification and tracking methods should be used to obtain robust conclusions for trends in cyclone characteristics as well as their relation to the large-scale circulation in the subantarctic region.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)

UniBE Contributor:

Raible, Christoph

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

0280-6495

Publisher:

Blackwell Munksgaard

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

08 May 2018 10:10

Last Modified:

23 Oct 2019 08:27

Publisher DOI:

10.1080/16000870.2018.1454808

BORIS DOI:

10.7892/boris.116227

URI:

https://boris.unibe.ch/id/eprint/116227

Actions (login required)

Edit item Edit item
Provide Feedback