On the development of strong ridge episodes over the eastern North Atlantic

Santos, J. A., Pinto, J. G. and Ulbrich, U. (2009) On the development of strong ridge episodes over the eastern North Atlantic. Geophysical Research Letters, 36 (17). L17804. ISSN 0094-8276 doi: 10.1029/2009GL039086

Abstract/Summary

The occurrence of strong and persistent mid-latitude anticyclonic ridges over the Eastern North Atlantic is a major contributor to the occurrence of severe winter droughts over Western Iberia. We analyze the development of strong and persistent ridge episodes within 40–50°N; 40°W–5°E, which are defined as 300 hPa geopotential height anomalies above 50 gpm that persist for at least 10 consecutive days. Results suggest that the generation and maintenance of these episodes, with positive stratospheric geopotential anomalies over the North American continent and the adjacent North Pacific, are associated with an intensified polar jet. Such positive anomalies tend to detach from the main stratospheric anomaly and propagate eastwards and downwards as Rossby tropospheric waves. Furthermore, the Eastern North Atlantic ridge is generated and repeatedly reinforced until the stratospheric anomaly dissipates. Results also show evidence for waves breaking anticyclonically during the episodes, which is dynamically coherent with their persistency and quasi-stationarity.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/32779
Identification Number/DOI	10.1029/2009GL039086
Refereed	Yes
Divisions	No Reading authors. Back catalogue items Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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