Accéder directement au contenu Accéder directement à la navigation
Nouvelle interface
Article dans une revue

Influence of Reduced Winter Land–Sea Contrast on the Midlatitude Atmospheric Circulation

Abstract : Even though winter land–sea thermal contrast (LSC) is expected to undergo a strong weakening in the future warmer climate, its effects have been poorly investigated. Here we run a set of idealized winter simulations featuring reduced LSC in the Northern Hemisphere (NH) extratropics, or in individual extratropical sectors of the NH (Atlantic and Pacific), using an intermediate-complexity atmospheric general circulation model. Reduced LSC is obtained by imposing a warming of surface land temperatures in East Asia and North America. For similar warming intensities over the two regions, the response of the model to East Asia forcing is significantly stronger and dominates the response to the sum of the two forcing patterns. We find that the LSC reduction causes a weakening and poleward shift of the midlatitude jet streams, and a strong interference with zonal wavenumbers 1 and 2. In particular, East Asian warming reduces the amplitude of waves 1 and 2, producing a strengthening of the stratospheric vortex, while a weaker vortex due to a moderate amplification of wave 1 is detected when warming North America. Eventually, stratospheric signals propagate downward in the troposphere affecting the midlatitude winter NH even remotely from the forcing. In this work we pinpoint some mechanisms by which weakened winter LSC influences the NH extratropical circulation: the results may become useful to interpret the response to long-term projections displaying reduced LSC along with other climate change forcing patterns.
Liste complète des métadonnées

https://hal.archives-ouvertes.fr/hal-03869011
Contributeur : Fabio D'Andrea Connectez-vous pour contacter le contributeur
Soumis le : jeudi 24 novembre 2022 - 09:59:51
Dernière modification le : lundi 28 novembre 2022 - 17:22:06

Fichier

1520-0442-JCLI-D-21-0941.1.pdf
Publication financée par une institution

Identifiants

Citation

Alice Portal, Claudia Pasquero, Fabio D’andrea, Paolo Davini, Mostafa Hamouda, et al.. Influence of Reduced Winter Land–Sea Contrast on the Midlatitude Atmospheric Circulation. Journal of Climate, 2022, 35 (19), pp.2637-2651. ⟨10.1175/JCLI-D-21-0941.1⟩. ⟨hal-03869011⟩

Partager

Métriques

Consultations de la notice

0

Téléchargements de fichiers

0