Generation of the additional topographic parameters for the new orographic drag scheme considering orographic anisotropy for all flow directions

The newly implemented suite of orographic drag schemes into E3SM has inputs to the model in addition to the PHIS, SGH, SGH30 listed in this section. This is used to consider the orographic anisotropy for all flow directions in the new orographic gravity wave drag (oGWD) and flow-blocking drag (FBD) scheme (Xie et al., 2020) implemented in E3SM.

The additional inputs include orographic asymmetry (OA), effective orographic length in the crosswind and along-wind direction (OL/OLP), and orographic convexity (OC). For details of these parameters, please refer to Xie et al., (2020).

For PHIS, SGH, and SGH30, we follow the current generation of topography shown here Atmospheric Topography Generation for different versions of E3SM.

For generation of the OA, OL/OLP, OC, we implemented a formation of the parameters onto the topographic generation tool now used in E3SM. The reference for the tool codebase is at Lauritzen et al., (2015).

The steps for creating the parameters is similar to that of the SGH and others using this cube_to_target tool (code/components/eam/tools/orographic_drag_toolkit, for reference check https://github.com/E3SM-Project/E3SM/pull/6667), we use the generation of the topographic parameters on ne30pg2 grid as an example, shown as follows:
a. we generate the SCRIP mesh file for the ne30pg2

#Tempest-remap_generation.sh
# Generate the element mesh.
${tempest_root}/bin/GenerateCSMesh --alt --res 30 --file topo2/ne30.g
# Generate the target physgrid mesh and SCRIP file:
${tempest_root}/bin/GenerateVolumetricMesh --in topo2/ne30.g --out topo2/ne30pg2.g --np 2 --uniform
${tempest_root}/bin/ConvertMeshToSCRIP --in topo2/ne30pg2.g --out topo2/ne30pg2_scrip.nc

b. we input the ne30pg2_scrip.nc for the generation of topographic parameters (chrysalis as an example)

make
        ${tool_root}/cube_to_target \
          --target-grid  ${tool_root}/topo2/ne30pg2_scrip.nc \
          --input-topography /lcrc/group/e3sm/data/inputdata/atm/cam/hrtopo/USGS-topo-cube3000.nc \
          --output-topography  ${tool_root}/topo2/ne30pg2_topo.nc

c. append the new parameters to the original file and rename it (or use ncl scripts):

cp USGS-gtopo30_ne30np4pg2_x6t-SGH.c20210614.nc USGS-gtopo30_ne30np4pg2_16xdel2_forOroDrag.c20241029.nc
ncks -A -v OA,OL,OC. ne30pg2_topo.nc   USGS-gtopo30_ne30np4pg2_16xdel2_forOroDrag.c20241029.nc
(an altenative way is to use make.ncl under the directory)

Notes:

The generation of the orographic anisotropy parameters are directly on targeted grid, different from that of SGH generation.