Tropical precipitation influencing boreal winter midlatitude blocking.

Gollan, Gereon , Bastin, Swantje and Greatbatch, Richard John (2019) Tropical precipitation influencing boreal winter midlatitude blocking. Open Access Atmospheric Science Letters, 20 (5). e900. DOI 10.1002/asl.900.

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Recent studies using reanalysis data and complex models suggest that the Tropics influence midlatitude blocking. Here, the influence of tropical precipitation anomalies is investigated further using a dry dynamical model driven by specified diabatic heating anomalies. The model uses a quasi‐realistic setup based on idealized orography and an idealized representation of the land‐ocean thermal contrast. Results concerning the El Niño Southern Oscillation and the Madden‐Julian Oscillation are mostly consistent with previous studies and emphasize the importance of tropical dynamics for driving the variability of blocking at midlatitudes. It is also shown that a common bias in models of the Coupled Model Intercomparison Project Phase 5 (CMIP5), namely, excessive tropical precipitation, leads to an underestimation of midlatitude blocking in our model, also a common bias in the CMIP5 models. The strongest blocking anomalies associated with the tropical precipitation bias are found over Europe, where the underestimation of blocking in CMIP5 models is also particularly strong.

Document Type: Article
Keywords: blocking bias, CMIP5, dry atmospheric general circulation model, ENSO, Midlatitude blocking, MJO, precipitation bias
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-OD Ocean Dynamics
Refereed: Yes
Open Access Journal?: Yes
Publisher: Royal Meteorological Society, Wiley
Related URLs:
Projects: MiKlip2, ATMOS-MODINI, Opendap
Date Deposited: 26 Apr 2019 09:50
Last Modified: 31 Jan 2022 09:16

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