Index Geophysics

The Role of Rossby-Wave Propagation in a North American Extreme Cold Event

The Eliassen–Palm flux and Plumb wave activity flux are calculated using the European Centre for Medium-Range Weather Forecasts interim reanalysis daily dataset to determine the propagation of Rossby waves before a North American cold wave in January 2014. The results show that the upward wave activity fluxes mainly come from planetary waves 1 and 2, which provide a stable circulation background for the influence of the subplanetary-scale waves 3 and 4. The Rossby-wave propagation anomalies between the troposphere and the stratosphere are due to the modulating effects of waves 3 and 4 on waves 1 and 2. During 9–14 January 2014, the modulating effects helped strengthen upward and eastward wave activity fluxes over the Atlantic region and enhance the Pacific high in the stratosphere in its early stage. Later in 19–24 January, the downward wave activity fluxes over the east Pacific due to the modulating effects were beneficial to downward development of the stratospheric high over the Pacific and the formation of a blocking high over the west coast of North America in the troposphere accompanied by a strong adjacent cold low on the east side. These circulations benefit the southward invasion of polar cold air reaching the lower latitudes of east North America, leading to the cold wave outbreak.

Chunhua Shi

Ting Xu

Hui Li

Yannan Gao

Meteorology. Climatology

QC851-999

Hindawi Limited

2017-01-01T00:00:00Z

article

1687-9309

1687-9317

10.1155/2017/4635849

https://doaj.org/article/3fbbcdbfbbeb4d6190eb53b7055c37a1

Advances in Meteorology, Vol 2017 (2017)

EN

http://dx.doi.org/10.1155/2017/4635849

https://doaj.org/toc/1687-9309

https://doaj.org/toc/1687-9317

Journal Licence: CC BY