Feb 15, 1998 - James H. Morison. Polar Science ... been conducted by Kozo [1983], Smith and Morison [1993], and. Kantha [1995]. .... k s - BsV4S -Jr- Qs (6).
JOURNAL OF GEOPHYSICAL
RESEARCH,
VOL. 103, NO. C2, PAGES 3233-3247, FEBRUARY
15, 1998
Nonhydrostatic haline convectionunder leads in sea ice David
C. Smith IV
EnvironmentalFluid DynamicsProgram,Mechanicaland AerospaceEngineeringDepartment Arizona State University,Tempe
James H. Morison Polar ScienceCenter,Applied PhysicsLaboratory,Universityof Washington,Seattle Abstract.
The distribution
of dense brine under leads in sea ice is associated with
convectivesinkingof individualplumesand near-surfacemixingassociated with ice-water momentumflux. The processes havebeen studiedin the recentLead Experiment (LeadEx) field programand previouslymodeledusinga two-dimensional hydrostatic numericalmodel. In this studytheseprocesses are reexaminedusinga nonhydrostatic model. It is shownthat nonhydrostatic effectsgive rise to pressuredistributionswhich counterhydrostaticpressuregradientsin the fluid. These effectsare largestin sinking plume eventsand can be substantialwhen plumesare free to sink to depthsof 100 m. In the presenceof the Arctic halocline(typicallyat 30-40 m), however,verticalaccelerations of convectiveplumesare limited spatiallyand temporally,and nonhydrostatic effectsare relativelysmall.It is the purposeof this paper to demonstratethat for realisticArctic stratification,convectivecirculationsunder leadsin sea ice are predominantlyhydrostatic. 1.
