Accueil > Actualités > Séminaires > Séminaire de Jacopo Riboldi


Titre : Quantifying the effects of Arctic Amplification on midlatitude Rossby waves employing spectral analysis
Nom du conférencier : Jacopo Riboldi
Son affiliation : LMD-ENS
Laboratoire organisateur : LMD
Date et heure : 18-01-2021 11h00
Lieu : En ligne
Résumé :

The reduction in the Arctic-to-midlatitude temperature gradient, related to the rapid progression of global warming over high latitudes, has the potential to reconfigure the background flow in which midlatitude Rossby waves form and propagate. Among the hypothesized effects of this phenomenon, known as Arctic Amplification, there are 1) a reduction in the eastward propagation of upper-level troughs and ridges, that would reverberate in an increased persistence of weather conditions, and 2) the development of quasi resonant, stationary Rossby waves with preferred wavenumbers. Both these problems can be tackled with spectral analysis, that provides a compact decomposition of the Rossby wave pattern in a series of wavenumber/phase speed harmonics and highlights at the same time which harmonics are active over the Northern Hemisphere in each considered time period. This analysis is also a first step to obtain a high frequency, global metric of Rossby phase speed, that is employed to investigate trends in the stationarity of weather patterns and its relationship with the Arctic amplification signal.

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