Difference between the arps_01 and arps_02 runs:

```bash
(mypy36) [serafin@jet01 ARPS]$ diff arps_01.input arps_02.input
255,256c255,256
<      cfcm4h  = 5.0e-4,
<      cfcm4v  = 5.0e-4,
---
>      cfcm4h  = 1.0e-4,
>      cfcm4v  = 1.0e-4,
```

where:

```bash
!  cfcm4h   4th order horizontal computational mixing coefficient scaled
!           by horizontal grid spacing (1/s).
!  cfcm4v   4th order vertical computational mixing coefficient scaled
!           by vertical grid spacing (1/s).
```

The scalar advection scheme in ARPS is 4th order, so computational mixing is needed in order to dissipate 2dx noise.