Impact of Eurasian autumn snow on the winter North Atlantic Oscillation in seasonal forecasts of the 20th century

Wegmann, Martin; Orsolini, Yvan; Weisheimer, Antje; van den Hurk, Bart; Lohmann, Gerrit

doi:https://doi.org/10.5194/wcd-2-1245-2021

Articles | Volume 2, issue 4

https://doi.org/10.5194/wcd-2-1245-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/wcd-2-1245-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 2, issue 4

Research article

|

16 Dec 2021

Research article |

| 16 Dec 2021

Impact of Eurasian autumn snow on the winter North Atlantic Oscillation in seasonal forecasts of the 20th century

Martin Wegmann, Yvan Orsolini, Antje Weisheimer, Bart van den Hurk, and Gerrit Lohmann

Supplement

https://doi.org/10.5194/wcd-2-1245-2021-supplement

Data sets

Public Datasets European Centre for Medium-Range Weather Forecasts https://apps.ecmwf.int/datasets/

North Atlantic Oscillation Climatic Research Unit https://crudata.uea.ac.uk/cru/data/nao/

Initialised seasonal forecast of the 20th Century Centre for Environmental Data Analysis https://catalogue.ceda.ac.uk/uuid/6e1c3df49f644a0f812818080bed5e45

Short summary

Northern Hemisphere winter weather is influenced by the strength of westerly winds 30 km above the surface, the so-called polar vortex. Eurasian autumn snow cover is thought to modulate the polar vortex. So far, however, the modeled influence of snow on the polar vortex did not fit the observed influence. By analyzing a model experiment for the time span of 110 years, we could show that the causality of this impact is indeed sound and snow cover can weaken the polar vortex.