7.3 Vertical diffusion

7.3.1 Introduction

Computed online using wind, temperature etc.

Originally based on [Louis, 1979]. Improved by [Holtslag and Boville, 1993], Vogelezang and Holtslag (1996), and Beljaars and Viterbo (1999).

In [Olivié et al., 2004], the diffusion in TM5 is extensively disscussed (see also thesis [Olivié, 2005]). A comparison has been made between offline computed diffussion coefficients (from TMPP) with archived diffusion (ERA40). The ERA40 archived coefficients give an overall stronger diffusion. Top up to where diffusion is important is therefore somewhat higher. The offline computed diffusion is however very well able to reproduce the archived fields.

7.3.2 Implementation

Vertical diffusion is applied in a combined convection/diffusion process.

7.3.3 History

Some important changes. Note that the date is one day after the day the change was committed; use this date to extract versions from the cvs server (see section ).

date	changes
2005-06-24	Improved vertical diffusion (computation of wind).

7.3.4 Offline kzz files

The offline kzz files are not supported anymore. If you really think that you need the offline diffusion, you are free to stay in your cave and re-implement it yourself.