85th AMS Annual Meeting

Wednesday, 12 January 2005: 9:00 AM
On the feedbacks between cloud dynamics and ice breeze
Alexander Avramov, Penn State University, University Park, PA; and J. Y. Harrington, P. Q. Olsson, and J. Verlinde
Although the Arctic region is often considered to be more or less uniform environment, a variety of mesoscale processes can be found anywhere that surface heterogeneity exists. A pronounced example is the ice-breeze circulation, which owes its existence to the marginal ice zone - one of the most significant surface boundaries present in Arctic. The differences in the surface albedo, latent and sensible fluxes and surface stress between ice- and oceanward side of the marginal ice zone, as well as the larger vertical component of planetary vorticity result in a balanced circulation which is stronger than in mid-latitudes. These strong circulations have an impact on ice motion within the MIZ and likely have strong impacts on cloud cover. Previous modeling studies have shown that the evolution of the circulation is most sensitive to the difference of the surface temperatues and to the background synoptic-scale flow. In most of the cases transient jet-like features develop along the boundary as a result of the intensifying horizontal temperature gradient. The intent of our study is to examine the impact of this circulation on clouds extent and structure using a nested version of the RAMS model with explicit microphysics. Since such impacts are likely symbiotic, we also examine whether cloud microphysics and dynamics influence the structure and evolution of the ice-breeze circulations. Implications for Arctic coastal regions will also be discussed.

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