EUROCS Intercomparison for Single Column Models
Diurnal Cycle of Cumulus Clouds over land
Geert Lenderink and Pier Siebesma
The present SCM intercomparison is based on
the 6th GCSS WG
1 intercomparison case. This case is based on observations at the ARM site on the Southern Great
Plains (USA) on 21st june 1997. During that day Cumulus clouds
at the top of an initially clear convective boundary layer. The
intercomparison case has been developed and coordinated by Andy Brown
(UKMO), responsible for the LES models, and Adrian Lock (UKMO),
responsible for the SCM models. The original case description by Andy
Brown can be obtained here
Results of several LES models have been presented at a meeting in Boulder, January 2000. On average, the LES results agreed rather well with each other. All models produced Cumulus clouds in reasonable correspondece with the measurements. Some results of the LES models can be obtained by anonymous ftp to email.meto.gov.uk (cd pub/apr/arm).
However, results of SCMs differed more strongly, and did not match the LES results as closely. Although most SCMs were able to simulate a Cumulus cloud, the SCMs typically suffered from the following deficiencies:
As a first step to tackle these problems we
request you to run (or repeat) the GCSS case.
So what to do ?
If you have not sent in a model description, please do so now.
In a latter stage, we will define a set of sensitivity runs. We will also perform LES runs to answer specific questions resulting from the SCM results. These will probably include several closure assumptions, like cloud base massflux.
|Case release||1 September 2000|
|Sent in results||15 May 2001 ***|
|Workshop Lisbon||28-31 May 2001|
*I** THIS IS A HARD DEADLINE: RESULTS SENT IN AFTER THIS DEADLINE
WILL NOT BE PROCESSED !!!!