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SE = Atmosphere spectral element dycore mesh ( CAM-SE Grid Overview ). Usually in "np4" configuration where each element has a 4x4 array of GLL nodes.
GLL = stands for "Gauss-Lobatto-Legende" quadrature, but we often use it to refer to the quadrature "nodes" that define the SE grid. Although quantities are technically continuous and differentiable on the SE grid, the discrete values live at the GLL nodes, which should be thought of as points rather than volumes or areas.
FV = MPAS finite volume mesh, the FV r05 and r0125 land and river runoff grids, and SE atmosphere "physgrids" pg2 and pg3 options.
Grid description/tempalte template files:
$atmgrid = SE Atmosphere grid in Exodus format. These are .g files.
$atmw = SE Atmosphere grid weights. These are _latlon.nc files
$ocngrid = FV MPAS grid file in "scrip" format. These are .scrip.nc files
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