Parametrizing turbulent exchange over summer sea ice and the marginal ice zone
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Authors
Andreas, Edgar L.
Horst, Thomas W.
Grachev, Andrey A.
Persson, P. Ola G.
Fairall, Christopher W.
Guest, Peter S.
Jordan, Rachel E.
Subjects
Arctic Ocean
bulk turbulent flux algorithm
drag coefficient
fictitious correlation
Monin- Obukhov similarity
roughness lengths
SHEBA
turbulence measurements
bulk turbulent flux algorithm
drag coefficient
fictitious correlation
Monin- Obukhov similarity
roughness lengths
SHEBA
turbulence measurements
Advisors
Date of Issue
2010-04
Date
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Abstract
The surface of the Arctic Ocean in summer is a mix of sea ice and water in both leads
and melt ponds. Here we use data collected at multiple sites during the year-long
experiment to study the SurfaceHeatBudget of the Arctic Ocean (SHEBA)to develop
a bulk turbulent flux algorithm for predicting the surface fluxes of momentum and
sensible and latent heat over the Arctic Ocean during summer from readily measured
or modelled quantities. The distinctive aerodynamic feature of summer sea ice is
that the leads andmelt ponds create vertical ice faces that the wind can push against;
momentum transfer to the surface is thus enhanced through form drag. In effect,
summer sea ice behaves aerodynamically like themarginal ice zone, which is another
surface that consists of sea ice and water. In our bulk flux algorithm, we therefore
combine our SHEBA measurements of the neutral-stability drag coefficient at a
reference height of 10 m, CDN10, with similar measurements from marginal ice
zones that have been reported in the literature to create a unified parametrization
for CDN10 for summer sea ice and for anymarginal ice zone. This parametrization
predicts CDN10 from a second-order polynomial in ice concentration. Our bulk flux
algorithm also includes expressions for the roughness lengths for temperature and
humidity, introduces new profile stratification corrections for stable stratification,
and effectively eliminates the singularities that often occur initerativeflux algorithms
for very light winds. In summary, this new algorithm seems capable of estimating the
friction velocity u∗ (a surrogate for the momentum flux) over summer sea ice with
an absolute accuracy of 0.02–0.03 m s−1; the sensible heat flux, with an accuracy of
about 6Wm−2; and the latent heat flux, with an accuracy of 3.5Wm−2.
Type
Article
Description
The article of record as published may be located at http://dx.doi.org/10.1002/qj.618
Series/Report No
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Meteorology
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Sponsors
Both NSF (award 06-11942) and the National Aeronautics and Space Administration (award NNX07AL77G) supported ELA at NorthWest Research Associates during the preparation of this manuscript, and NSF also supported POGP with award 06-12428.
Funder
Format
Citation
Andreas EL, Horst TW, Grachev AA, Persson POG, Fairall CW, Guest PS, Jordan RE. 2010.
Parametrizing turbulent exchange over summer sea ice and themarginal ice zone. Q. J. R. Meteorol. Soc. 136:
927–943. DOI:10.1002/qj.618
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.