Development processes for five depression systems within the Polar Basin

• Published in: Journal of Climatology
• Main Author: Ledrew, Ellsworth F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1988
• Subjects: Arctic; Greenland
• Online Access: http://dx.doi.org/10.1002/joc.3370080203; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.3370080203; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.3370080203

Abstract Five synoptic sequences in the Polar Basin are studied on a day by day basis. A diagnostic model is used to illustrate the relative roles of the dynamic properties of the advected air flow in comparison to mechanisms related to the characteristics of the underlying surface. It is found that the properties of the advected air flow are the major contribution to the vertical circulation associated with synoptic evolution and are a necessary condition. Latent heat release may also be a significant mechanism which supports the proposal by others that a CISK type process may contribute to further development in the Arctic. The surface sensible heat flux is not a necessary process and it may at times oppose the vertical circulation when warm air is advected into the region of development within the circulation of the depression. The surface frictional effect is a minor contribution within the central Polar Basin but is a significant process in systems migrating along the Asiatic coastline. A feedback linkage between synoptic evolution and intensification of the baroclinicity is proposed in the Greenland region for a cold low type of vortex. A cold pool, apparently created by intense radiative cooling over Greenland, was identified in early July. There was significant advective convergence associated with the thermal gradients which contributed to synoptic development as the depression migrated around this pool. It appears that the intensification of the potential temperature gradient with the advection maintained the baroclinicity, despite warm air advection into the centre of the pool. This is an interesting feature which requires further study and confirmation.