www.helsinki.fi/ yliopisto 24.10.11 Department of Physics /Victoria Sinclair www.atm.helsinki.fi/~vsinclai Structure and force balance of idealised cold fronts simulated with WRF [email protected]1. University of Helsinki, Division of Atmospheric Sciences 2. University of Albany, Department of Atmospheric and Environmental Sciences Victoria Sinclair 1 and Dan Keyser 2
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Structure and force balance of idealised cold fronts simulated with WRF
Structure and force balance of idealised cold fronts simulated with WRF. [email protected] University of Helsinki, Division of Atmospheric Sciences University of Albany, Department of Atmospheric and Environmental Sciences. Victoria Sinclair 1 and Dan Keyser 2. Scientific Aims. - PowerPoint PPT Presentation
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www.helsinki.fi/yliopisto 24.10.11Department of Physics /Victoria Sinclairwww.atm.helsinki.fi/~vsinclai
Structure and force balance of idealised cold fronts simulated
www.helsinki.fi/yliopisto 24.10.11Department of Physics /Victoria Sinclairwww.atm.helsinki.fi/~vsinclai
Force balance in d03 (dx=4km)
Green: Wind Vectors Blue: Coriolis ForceRed: Pressure gradient force Black: Resultant accelerationPurple: BL force
www.helsinki.fi/yliopisto 24.10.11Department of Physics /Victoria Sinclairwww.atm.helsinki.fi/~vsinclai
Rossby Number = Acc / Cor
Narrow region of unbalanced flow co-located with the surface front and with the ascent plume above the surface front
Z=100m
Z=2.5 km
www.helsinki.fi/yliopisto 24.10.11Department of Physics /Victoria Sinclairwww.atm.helsinki.fi/~vsinclai
Conclusions
Realistic frontal structure can be simulated with idealised WRF
The force balance changes with model resolution Low resolution: approximate geostrophic balance, no
unbalanced regions
High resolution: pressure gradient force in unbalanced
Rossby number > 1 in a narrow band along the surface front and above the surface front
www.helsinki.fi/yliopisto 24.10.11Department of Physics /Victoria Sinclairwww.atm.helsinki.fi/~vsinclai
Future plans and challenges with WRF
Increase size of nested domains and add a 4th domain.
Output the diffusion term
Attempt to simulate different cold fronts Different baroclinic life cycle e,g, LC1 / LC2 Deformation forced front 2-dimensional experiments – repeat previous experiments