Observations and modelling of Dense Water Cascading from the Laptev Sea Shelf

Project

• Introduction
• Objectives

Data Analysis:

• • Hydrographic
• • Meteorological and Ice

Numerical Modeling:

• • Model Description
• • Experiments

• Conclusions
• Summary
• References

 

• People
• Funding

Numerical Modeling: Model Description

POLCOMS model (brief overview)

POLCOMS is Proudman Oceanographic Laboratory COmmunity Modeling System (Holt and James, 2001; http://www.pol.ac.uk/home/research/polcoms/).

Basic features:

• Spherical polar coordinates, Arakawa B-grid
• Incompressible, hydrostatic, Boussinesq equations of motion
• Time splitting between baroclinic and barotropic components
• Transport equations for temperature and salinity
• Pressure-dependent equation of state for sea water
• Melor-Yamada-Galperin level 2.5 turbulence closure scheme
• Vertical convection adjustment

Specific features:

• `Piecewise Parabolic Method' (PPM, Colella and Woodward, 1984) advection scheme
• s-coordinates (Song and Heidvogel, 1996) in vertical direction
• Pressure gradient calculations are made by interpolation onto horizontal planes
• Horizontal viscosity may be set to zero

Fig. 11

Experimental Set up Grid area 330x330 km, horizontal step: 1.7-2.0 km 36 levels, vertical step 1.4 -100 m (the largest step in BBL – 2.5 m) Barotropic time step is 4 sec, baroclinic step is 480 sec Horizontal viscosity is 20 m2/s Boundary conditions: (i) at the free surface: constant salt flux 1.66x10-5 (kg/m2/s), no wind stress, no heat flux; (ii) at the bottom: logarithmic law of the wall for velocity, zero scalar gradients (iv) at side walls zero velocities and zero scalr gradients; (iv) at open boundaries: flux/radiation and discharge, advection of scalars E1 – model topography no stratification; E2 – “real” topography, horizontally uniform T ad S stratification (Fig. 11)