I was looking through a few of the MOM6 F90 files where slopes are defined: MOM_isopycnal_slopes.F90 (e.g line 325) or MOM_thickness_diffuse.F90 (e.g. line 994).
I noticed that the slope is defined as (for example):
```
slope = (e(i,j,K)-e(i+1,j,K)) * G%IdxCu(I,j)
```
I am wondering why is this definition of slope = - d \eta /dx used, which also corresponds to (d_x \rho /d_z \rho)? Rather than the more standard definition, which would have a minus in front of what is used (d \eta/dx or - d_x \rho /d_z \rho)?
(*Or maybe I am just being thick)
I noticed that the slope is defined as (for example):
```
slope = (e(i,j,K)-e(i+1,j,K)) * G%IdxCu(I,j)
```
I am wondering why is this definition of slope = - d \eta /dx used, which also corresponds to (d_x \rho /d_z \rho)? Rather than the more standard definition, which would have a minus in front of what is used (d \eta/dx or - d_x \rho /d_z \rho)?
(*Or maybe I am just being thick)