Decadal variations of blocking and storm tracks in centennial reanalyses

Rohrer, Marco; Brönnimann, Stefan; Romppainen-Martius, Olivia; Raible, Christoph; Wild, Martin (2019). Decadal variations of blocking and storm tracks in centennial reanalyses. Tellus. Series A - dynamic meteorology and oceanography, 71(1), pp. 1-21. Taylor & Francis 10.1080/16000870.2019.1586236

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Extreme weather events in the mid-latitudes are often associated with weather systems, such as extratropicalcyclones or blocks. However little is known about the decadal variation in the frequency of blocks and th eactivity of storm tracks and their relation to the two most important low-frequency oceanic modes ofvariability, the Atlantic multidecadal oscillation (AMO) and the Pacific decadal oscillation (PDO). To address this question, first the representation of blocks, storm tracks and Alpine circulation types is assessed in recently released centennial reanalyses during the 20th century.While interannual variability is represented similarly in all centennial reanalyses, the trends in particular forstorm track activity before 1950 differ substantially between the NOAA 20th century reanalyses (20CR and20CRv2c) and ECMWF centennial reanalyses (ERA-20C and CERA-20C). Therefore, the analysis of theconnection between the AMO and PDO and the mid-latitudinal circulation is restricted to the period 1950–2010. All centennial reanalyses agree on the anomaly patterns associated with the different AMO/PDO phases. We find no significant connections except a southward (northward) shift of the storm track over the North Pacific as well as the North Atlantic during the positive (negative) PDO phase. The ERA-20CM atmosphere-only model ensemble captures this relationship, indicating that the ocean forces the atmospherein the North Pacific. For studies investigating periods earlier than 1950, we recommend using severalreanalysis products to ensure the robustness of results.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography
08 Faculty of Science > Physics Institute > Climate and Environmental Physics

UniBE Contributor:

Rohrer, Marco; Brönnimann, Stefan; Romppainen-Martius, Olivia and Raible, Christoph

Subjects:

900 History > 910 Geography & travel
500 Science > 530 Physics

ISSN:

0280-6495

Publisher:

Taylor & Francis

Language:

English

Submitter:

Christoph Raible

Date Deposited:

21 May 2019 17:23

Last Modified:

21 May 2019 17:23

Publisher DOI:

10.1080/16000870.2019.1586236

BORIS DOI:

10.7892/boris.129936

URI:

https://boris.unibe.ch/id/eprint/129936

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