tools for displaced-pole ocean grid generation for ccsm2
DESCRIPTION
Tools for Displaced-Pole Ocean Grid Generation for CCSM2. Steve Yeager Rick Smith Esther Brady John Davis. What needs to be modified?. OCN horiz_grid :ieee r8, {ulat,ulng,htn,hte,hus,huw,utan} topography : ieee i4, {kmt} region_mask : ieee i4 {regionmask} - PowerPoint PPT PresentationTRANSCRIPT
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Tools for Displaced-PoleOcean Grid Generation for CCSM2
Steve Yeager Rick SmithEsther Brady John Davis
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What needs to be modified?1. OCN
horiz_grid : ieee r8, {ulat,ulng,htn,hte,hus,huw,utan}topography : ieee i4, {kmt}region_mask : ieee i4 {regionmask}other input_template files…
2. CPLmap_ATM_to_OCN_aave.ncmap_ATM_to_OCN_bilin.ncmap_OCN_to_ATM_aave.ncmap_RUNOFF_to_OCN.nc
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Tools
ns_dipole.F generates a dipole mesh grid, (R Smith et al)
topography.F Generates a kmt based on etopo5 data, (R Smith et al)
paleotopo.F90 Generates a kmt based on paleo data
display_hgrid_land.F Grid display with land mask, (R Smith et al)
eCubed (C++ package) Interactive grid display & kmt edit, (J Davis et al)
grid_bin2nc.F90 Creates a netcdf file of grid info
gridkmt_nc2bin.F90 Writes kmt in netcdf back into binary
ncview (C++ package) All-purpose netcdf viewer (D Pierce) (http://meteora.ucsd.edu/~pierce/ncview_home_page.html)
SCRIP (F90 package) Remapping between grids (P Jones) (http://climate.acl.lanl.gov/software/SCRIP/scrip_frames.htm) (http://www.cgd.ucar.edu/csm/models/ocn-pop/scrip.shtml)
mk_grid.csh Automates grid generation procedure, including grid & kmt
mk_ocninput.csh Automates ocn input file modification, including region mask
mk_remap.csh Automates atmosphereocean map generation
mk_runoff_remap.csh Automates runoffocean map generation
map_runoff (F90 package) Correction routines for runoffocean map
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1. a. Generating a Grid
• ns_dipole* generates a dipole mesh grid with user-specified north/south pole locations.
• Equator is always a grid line• Enhanced meridional
resolution at the equator• Code tries to make aspect
ratio 1 • Nx is independent variable
(sets the order of the resolution); Ny requires iteration
Created using display_hgrid* (R Smith et al)
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1. b. Generating a kmt • topography* assigns topography/kmt
to a grid based on the 1/12 degree etopo5 dataset.
Created using display_hgrid_land*
• paleotopo* assigns topography/kmt to a grid based on a paleo bathymetry dataset in netcdf format.
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Iterate grid/kmt generation until
… for a given Nx and equatorial gaussian function, Ny is sufficient to extend the grid into the polar continents without wasting resolution,
… grid has acceptable min/max cell sides & aspect ratios for active ocean points (when compared to standard grids)
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1. c. Hand Edit Kmt
• eCubed* enables interactive grid-viewing/kmt-editing using a mouse & keyboard
• Reads/writes a grid netcdf file created with grid_bin2nc*
• Convert kmt back into POP input binary with gridkmt_nc2bin*
Created using display_hgrid_land*Created using eCubed*
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2. a. Maps between ATM & OCN
• mk_remap.csh creates atmosphereocean mappings using SCRIP (Spherical Coordinate Remapping and Interpolation Package) developed by Phil Jones.
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2. b. Mapping Runoff to OCN
• mk_runoff_remap.csh calls SCRIP; generates a conservative runoffocean mapping netcdf.
• BUT, it does not guarantee global water conservation• ALSO, it may require additional smoothing to prevent
excessively low ocean salinities in high runoff regions.
• Use map_runoff/*.F90 for – runoff map conservation correction– map matrix testing– ocean smoothing map generation & testing– map matrix multiplication.
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Why are conservation corrections needed?
Potential flux loss
…where an active source grid cell does not overlap any (a) or only partially overlaps (b) a destination cell.
…where an active source grid cell maps into an inactive destination cell (c)
runoff_conserve_mod.F90 applies corrections
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Runoff Smoothing
• runoff_smooth_mod.F90 contains routines for generating an ocean-to-ocean smoothing map
• Input parameters maxradius (km) & efold (km)
• test_smooth generates netcdf output of smoothing effects for select source points
efold = 100km, maxradius = 500km
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Runoff-to-Ocean Map with Smoothing
• runoff_map_mod.F90 contains routines for matrix multiplication & testing:
=
runoff grid ocean grid runoff grid
Final Map Smoothing Map Corrected SCRIP Map
o ce a
n g r
id
o ce a
n g r
id
o ce a
n g r
id
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efold = 100km, maxradius = 500km
efold = 2000km, maxradius = 500km
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Surface Salinity Effect of Smoothing Runoff