o 2nd-Order Moment Advection Scheme (Prather, 1986): first check-in  - enable by setting #define GAD_ALLOW_SOM_ADVECT (in GAD_OPTIONS.h)  - used without limiter (AdvScheme=80) or with Prather limiter (AdvScheme=81)  - still needs work (not working with some options ; efficiency to improve)    and serious testing.  - use this scheme for temperature & salinity in 2 advection test exp.:    advect_xy & advect_xz, respectively.
o 2nd-Order Moment Advection Scheme (Prather, 1986): first check-in
 - enable by setting #define GAD_ALLOW_SOM_ADVECT (in GAD_OPTIONS.h)
 - used without limiter (AdvScheme=80) or with Prather limiter (AdvScheme=81)
 - still needs work (not working with some options ; efficiency to improve)
   and serious testing.
 - use this scheme for temperature & salinity in 2 advection test exp.:
   advect_xy & advect_xz, respectively.

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