Page Comparison

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1. fluxes:  
   1. if source grid resolution uniformly  >> target grid resolution:  TR aave 
   2. otherwise:    FV2+CAAS 
2. state and vector maps:  
   1. ocn→atm: The state map's non-zero pattern must be a superset of the ocn→atm flux map.  
      1. ocn resolution uniformly >> atm resolution:  TR aave 
      2. otherwise:   FV2+CAAS   
   2. lnd↔atm and atm→ocn
      1. if source grid resolution uniformly >> target grid resolution (fine-to-coarse):  TR  ave aave or intbilin
      2. if source grid resolution uniformly << target grid resolution (coarse-to-fine):  TR bilin or intbilin  (bilin slightly faster)
      3. otherwise:   TR intbilin or FV2+CAAS  (intbilin slightly faster)
   3. riv → ocn
      1. continue to use custom maps generated by E3SM/cime/tools/mapping/gen_mapping_files/runoff_to_ocn

"FV2+CAAS" refers to the nonlinear approach from /wiki/spaces/COM/pages/3771301899 where an aave and 2nd order FV map are used with Compute-And-Assured-Sum (CAAS) to provide a monotone conservative map that avoids the blocky artifacts of aave maps and is more accurate than aave maps.  FV2+CAAS is comparable in accuracy to intbilin, adds conservation, but could be slightly more is more expensive.  

E3SMv3 with pg2 simplified instructions.  Accurate robust maps, but will increase computational cost of coupler:    

1. fluxes:  FV2+CAAS
2. state:  FV2+CASSCAAS
3. riv → ocn
   1. continue to use custom maps generated by E3SM/cime/tools/mapping/gen_mapping_files/runoff_to_ocn

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