| task | description |
|---|---|
| kzz-old | compute diffusion on Gaussian grid, then average to TM grid; interpolate 3D fields to 3hr resolution |
| kzz-old2 | first average to TM grid, then compute diffusion; use same 6hr 3D field for two 3hr intervals |
| kzz | compute diffusion from TM fields: muv, t, q, surf3 (same resolution) |
| kzz-1x1 | compute diffusion from TM fields: muv, t, q (same resolution), and surf on 1x1 |
| task | description |
|---|---|
| kzz-kh | produces kzz files on 3x2 grid from old 'k' and 'h' files ERA40 'k' and 'h' files lack a record for [18,21], adhoc fixed |
The content version is an attribute in hdf files.
| content version | description |
|---|---|
| 3 | kzz extracted from blsurfgg |
| 4 | interpolate gg fields to TM resolution, then compute kzz |
| 5 | computed from TM fields on same resolution, BUG IN LEVEL ORDER |
| 6 | computed from TM fields on same resolution |
| 10 | computed from TM fields and 1x1 surface fields, BUG IN LEVEL ORDER |
| 11 | computed from TM fields and 1x1 surface fields |
| 111 | computed from TM fields and 1x1 surface fields, ADHOC BUG IN LEVEL ORDER FIX |
| 7 | BUG FIXED : in DIFCOEF, division by zero might occure in rare occasions |
| file | param | description | unit | levels | from | time res. (hr) | grib code | hor. comb. | vert. comb | Comments |
|---|---|---|---|---|---|---|---|---|---|---|
| kzz | Kz | diffusion coeff | m2/s | 1:lm | gg | [21,00],.. | 163 | none | bottom ?? | old file 'k'; to be reconsidered by Dirk ? |
| kzz | pblh | planetary boundary layer height | m | 1 | gg | [21,00],.. | 203 | none | - | old file 'h' |
Diffusion coeff and boundarly layer height used to be computed as a part of the deposition/surface preprocessing, but have become a seperate task while updating preprocessing for TM5.
In original preprocessing, a diffusion coeff was computed as a part of the convective subgrid stuff too (Louis scheme). Louis died during the conversion to TM5.
The vertical diffusion is computed directly on the target TM grid, that is, fields are not computed on one grid and then averaged over TM cells, and neither averaged over layers. The input to the kzz routine consists of fields defined on the target grid: temperature, humidity, mean wind, and some surface fields. Thus, these fields need to be created before the vertical diffusion is computed!
The diffusion is computed from 3 hourly accumulated surface fields and 6 hourly instantaneous 3D fields (mean wind, temperature, humidity). The instantaneous 3D fields are used twice, first for the previous 3 hour interval and then for the coming 3 hour interval.
Should the wind fields etc not be interpolated to 22:30, 01:30, ...?