Page Comparison

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• SE→FV mono. (conservative, monotone, 1st order)
  • ./GenerateOfflineMap --in_mesh $atmgrid --out_mesh $ocngrid --ov_mesh overlap_mesh.g --in_type cgll --in_np 4  --out_type fv  --mono --correct_areas --out_map map_atm2ocn_mono.nc
• SE→FV intbilin (nonconservative, monotone, higher order)
  • ./GenerateOfflineMap --in_mesh $atmgrid --out_mesh $ocngrid --ov_mesh overlap_mesh.g --in_type cgll --in_np 4  --out_type fv --mono3 --noconserve --correct_areas --out_map map_atm2ocn_intbilin.nc
• SE→FV highorder. (conservative, nonmonotone)
  • ./GenerateOfflineMap --in_mesh $atmgrid --out_mesh $ocngrid --ov_mesh overlap_mesh.g --in_type cgll --in_np 4  --out_type fv --correct_areas --out_map map_atm2ocn_highorder.nc
• FV→SE monotr. (conservative, monotone, 1st order)
  • The transpose of the SE→FV mono map: 
  • ./GenerateTransposeMap --in map_atm2ocn_mono.nc --out map_ocn2atm_monotr.nc
• FV→SE highorder. (conservative, non-monotone)
  • ./GenerateOfflineMap --in_mesh $ocngrid --out_mesh $atmgrid --ov_mesh overlap_mesh.g --in_type fv --in_np 2 --out_type cgll --out_np 4  --volumetric --out_map map_ocn2atm_highorder.nc
  • Does these maps need "–correct_areas" ?
• FV→SE mono. (conservative, monotone, 1st order)
  • ./GenerateOfflineMap --in_mesh $ocngrid --out_mesh $atmgrid --ov_mesh overlap_mesh.g --in_type fv --in_np 1 --out_type cgll --out_np 4 --volumetric --out_map map_ocn2atm_mono.nc
  • Does these maps need "–correct_areas" ?
• FV→SE intbilintr  (nonconservative, monotonenonmonotone, higher order)
  • The transpose of the SE→FV intbilin map.  No negative weights, but weights can be larger than 1.   
  • ./GenerateTransposeMap --in map_atm2ocn_intbilin.nc --out map_ocn2atm_intbilintr.nc
• FV→FV mono (conservative, monotone, 1st order)
  • The classic cell integrated piecewise constant map.  Equivalent to the ESMF "aave" map and NCO's built in map.  
  • ./GenerateOfflineMap --in_mesh $ocngrid --out_mesh $atmgrid --ov_mesh overlap_mesh.g --in_type fv --in_np 1 --out_type fv --out_np 1 -correct_areas  --out_map map_ocn2atm_mono.nc
• FV→FV highorder. (conservative, non-monotone, high order)
  • ./GenerateOfflineMap --in_mesh $atmgrid --out_mesh $ocngrid --ov_mesh overlap_mesh.g  --in_np 2 --in_type fv --out_type fv   --out_type fv  -correct_areas --out_map map_atm2ocn_highorder.nc

Recommended Settings:   Atm/Ocn maps for coupled simulations

UPDATE 2020/2/21:  Removing highorder maps which can have negative weights.  It's probably a bad idea to use negative weights in a coupled simulation, and we shouldn't recommend this without detailed evaluation.        

Recommended Settings:   For ATM SE grids coupled to FV ocean and FV land

1. SE → FV  for fluxes:  use "mono" 
2. SE → FV for state variables:  "highorder". ). not recommended.  
3. SE → FV for state variables:  intbilin?
4. FV → SE for fluxes:  monotr
   1. The best map is the transpose of the SE->FV map computed above:
   2. This is the most important map, as it is used to compute the domain files and defines the ocean/land mask on the atm/land grid.  
5. FV → SE for state variables and velocity:  highorder.   not recommended.  
   1. Tests with ocean120→NE30, analytic fields, show this map is more accurate than the transpose map. 
6. FV → SE mono.  
   1. This is also a good monotone/conservative map for fluxes, but not quite as accurate (in analytic tests) as the transpose map recommended above.  
7. FV → SE for state variables
   1. what should we recommend???
   2. for ocn→atm map, note that range must be identical to flux map, which usually forces us to use the same map for both flux and state.   

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1. 1. ocn→atm: currently this map must be the same as used for fluxes.     
   2. lnd->atm:   if land grid resolution >> atmosphere resolution:  "mono"  
   3. lnd→atm:   if land grid resolution <= atmosphere resolution:   ESMF's bilin.  
   4. DESIRED:  a version of intbilin for FV source grids.   

Recommended Settings:   For ATM FV grids (the new "pg2" option)  coupled to FV ocean and FV land

1. fluxes:  mono
2. state variables: highorder.  not recommendedstate variables:Source :
   1. ocn→atm: currently this map must be the same as used for fluxes.     
   2. lnd<->atm: 
      1. if source grid resolution >> target grid resolution:
       
      1.   "mono"
      1. bilinear interpolation produces blocky ugly results.  In this case we need a true downscaling algorithm
      1.   
      2. source grid resolution <= target grid
      resolution: "bilin"Desired: an equivalent of TR's "intbilin" algorithm
      1. resoluiton:  ESMF's bilin
   3. DESIRED:  a version of intbilin for FV source grids.  accurate, monotone and build in downscaling.  

Recommended Settings:   Atm to/from Lat/Lon maps for analysis and interpolating input data

For ESMF maps, we previously recommend bilinear maps for upscaling and aave for downscaling.  All the TempestRemap algorithms recommended here should work well for either upscaling or downscaling.  The choice depends mostly on the tradeoff between montonicity monotonicity and accuracy:

1. SE → Lat/Lon:   "intbilin"
   1. "intbilin" if exact conservation is not needed.
   2. "mono" if exact conservation is needed and 1st order accurate is ok (i.e. for downscaling).    

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