Merge branch 'cbegeman/ocn/fix-variable-descriptions' (PR #7472)

Clarify registry descriptions for avgSurface* variables

Surface values sent to the coupler are not actually extrapolated from
zMid to zTop as described. This PR changes the description of these
variables in the registry to make that more clear.

[BFB]

Author: jonbob

components/mpas-ocean/src/Registry.xml

@@ -3991,18 +3991,18 @@
 		/>
 		<var_array name="avgTracersSurfaceValue" type="real" dimensions="nCells Time" packages="forwardMode;analysisMode">
 			<var name="avgTemperatureSurfaceValue" array_group="surfaceValues" units="C"
-				 description="Time averaged potential temperature extrapolated to ocean surface"
+				 description="Time averaged potential temperature in the uppermost active level as determined by minLevelCell"
 			/>
 			<var name="avgSalinitySurfaceValue" array_group="surfaceValues" units="1.e-3"
-				 description="Time averaged salinity extrapolated to ocean surface"
+				 description="Time averaged salinity in the uppermost active level as determined by minLevelCell"
 			/>
 		</var_array>
 		<var_array name="avgSurfaceVelocity" type="real" dimensions="nCells Time" packages="forwardMode;analysisMode">
 			<var name="avgSurfaceVelocityZonal" array_group="vel_zonal" units="m s^-1"
-				 description="Time averaged zonal surface velocity"
+				 description="Time averaged zonal surface velocity located in minLevelCell"
 			/>
 			<var name="avgSurfaceVelocityMeridional" array_group="vel_meridional" units="m s^-1"
-				 description="Time averaged meridional surface velocity"
+				 description="Time averaged meridional surface velocity located in minLevelCell"
 			/>
 		</var_array>
 		<var_array name="avgSSHGradient" type="real" dimensions="nCells Time" packages="forwardMode;analysisMode">

components/mpas-ocean/src/shared/mpas_ocn_diagnostics.F

@@ -401,9 +401,9 @@ subroutine ocn_diagnostic_solve(dt, statePool, forcingPool, meshPool, verticalMe
 
       !
       ! extrapolate tracer values to ocean surface
-      ! this eventually be a modelled process
-      ! at present, just copy k=1 tracer values onto surface values
-      ! field will be updated below is better approximations are available
+      ! this eventually could be a modelled process
+      ! at present, just copy minLevelCell tracer values onto surface values
+      ! field will be updated below as better approximations are available
 
 !TDR need to consider how to handle tracersSurfaceValues
 #ifdef MPAS_OPENACC