An Advective Atmospheric Mixed-Layer Model for Ocean Modeling Purposes - Global Simulation of Surface Heat Fluxes

Publication Type  Journal Article
Year of Publication  1995
Authors  Seager, R.; Blumenthal, M. B.; Kushnir, Y.
Journal Title  Journal of Climate
Volume  8
Issue  8
Pages  1951-1964
Journal Date  Aug
ISBN Number  0894-8755
Accession Number  ISI:A1995RN69400003
Key Words  general-circulation model; tropical pacific-ocean; convective boundary-layer; cold-air outbreak; equatorial pacific; temperature; sensitivity; variability; parameterization; evaporation
Abstract  

A simple model of the lowest layer of the atmosphere is developed for coupling to ocean models used to simulate sea surface temperature (SST). The model calculates the turbulent fluxes of sensible and latent heat in terms of variables that an ocean model either calculates (SST) oris forced by (winds). It is designed to avoid the need to specify observed atmospheric data (other than surface winds), or the SST, in the surface flux calculations of ocean models and, hence, to allow a realistic representation of the feedbacks between SST and the fluxes. The modeled layer is considered to be either a dry convective layer or the subcloud layer that underlies marine clouds. The turbulent fluxes are determined through a balance of horizontal advection and diffusion, the surface flux and the flux at the mixed layer top, and, for temperature, radiative cooling. Reasonable simulations of the global distribution of latent and sensible heat flux are obtained. This includes the large fluxes that occur east of the Northern Hemisphere continents in winter that were found to be related to both diffusion (taken to be a parameterization of baroclinic eddies) and advection of cold, dry air from the continent. However, east of North America during winter the sensible heat flux is underestimated and, generally, the region of enhanced fluxes does not extend far enough east compared to observations. Reasons for these discrepancies are discussed and remedies suggested.

Notes  

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