Stationary wave biases and their effect on upward troposphere– stratosphere coupling in sub-seasonal prediction models
Details
Serval ID
serval:BIB_44C0BE276E02
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Stationary wave biases and their effect on upward troposphere– stratosphere coupling in sub-seasonal prediction models
Journal
Weather and Climate Dynamics
ISSN
2698-4016
Publication state
Published
Issued date
23/06/2022
Peer-reviewed
Oui
Volume
3
Number
2
Pages
679-692
Language
english
Abstract
The simulated Northern Hemisphere winter stationary wave (SW) field is investigated in 11 Subseasonal-to-Seasonal (S2S) prediction project models. It is shown that while most models considered can well simulate the stationary wavenumbers 1 and 2 during the first 2 weeks of integration, they diverge from observations following week 3. Those models with a poor resolution in the stratosphere struggle to simulate the waves, in both the troposphere and the stratosphere, even during the first 2 weeks. Focusing on the tropospheric regions where SWs peak in amplitude reveals that the models generally do a better job in simulating the northwestern Pacific stationary trough, while certain models struggle to simulate the stationary ridges in both western North America and the North Atlantic. In addition, a strong relationship is found between regional biases in the stationary height field and model errors in simulated upward propagation of planetary waves into the stratosphere. In the stratosphere, biases are mostly in wave 2 in those models with high stratospheric resolution, whereas in those models with low resolution in the stratosphere, a wave 1 bias is evident, which leads to a strong bias in the stratospheric mean zonal circulation due to the predominance of wave 1 there. Finally, biases in both amplitude and location of mean tropical convection and the subsequent subtropical downwelling are identified as possible contributors to biases in the regional SW field in the troposphere.
Web of science
Publisher's website
Open Access
Yes
Funding(s)
Swiss National Science Foundation / PP00P2_170523
Swiss National Science Foundation / PP00P2_198896
Create date
05/09/2022 14:31
Last modification date
10/07/2024 6:05