A Subgrid Orography Scheme: Ready for Prime Time Steven Ghan and Tim Shippert Pacific Northwest National Lab Ghan, S. J., X. Bian, A. G. Hunt, and A. Coleman, 2002: The thermodynamic influence of subgrid orography in a global climate model, Climate Dynamics, 20, 31-44.
A Subgrid Orography Scheme: Ready for Prime Time. Steven Ghan and Tim Shippert Pacific Northwest National Lab. Ghan, S. J., X. Bian, A. G. Hunt, and A. Coleman, 2002: The thermodynamic influence of subgrid orography in a global climate model, Climate Dynamics , 20 , 31-44. Subgrid scheme. - PowerPoint PPT Presentation
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A Subgrid Orography Scheme:Ready for Prime Time
Steven Ghan and Tim ShippertPacific Northwest National Lab
Ghan, S. J., X. Bian, A. G. Hunt, and A. Coleman, 2002: The thermodynamic influence of subgrid orography in a global climate model, Climate Dynamics, 20, 31-44.
Subgrid scheme
Implementation
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• Applies to all column physics– clouds– radiative transfer– vertical mixing– surface physics
Elevation ClassificationElevation Classifi cation
-10000
100020003000400050006000700080009000
Su
rfac
e E
leva
tio
n (
m)
Progress
• Scheme applied to CAM and CLM – Euler dycore– Finite-volume dycore
• Developmental branch updated to cam3.2.41• Bit-for-bit agreement between SP, SMP, SPMD• Restarts bit-for-bit agreement• Bit-for-bit agreement with dev trunk if subgrid scheme turned
off• Energy conservation demonstrated to within 0.01 Wm-2
• Load balancing within nodes for both dycores• Load balancing between nodes for both dycores (IJHPCA, 2005)• Runoff distributed according to elevation of river transport
model surface elevation• AMIP simulations at T42 and 2˚x2.5º resolution• Detailed evaluation in eight regions (J. Climate, 2006a)• IPCC A1B simulation 1977-2100 at 2˚x2.5˚ resolution (J.
Climate, 2006b)
Experiments
• AMIP SST – Initialize September 1977– Run through 1989– T42