Warm rain diagnostics (COSP and non-COSP)

Warm rain diagnostics (COSP and non-COSP)

Objective

Warm rain statistics may provide a process-based observational constraint on parameterized precipitation in GCMs, specifically on the cloud lifetime effect.

We have received base-state warm rain diagnostics from a number of models, but it would be especially useful to see how the warm diagnostics respond to changes in the warm rain (autoconversion/accretion) parameterization. We would therefore like to piggyback on existing AeroCom experiments (e.g., the multi-model PPE) with as little extra work as possible required for the modeling groups.

Required model diagnostics

If you are interested in participating and are COSP-enabled, please see COSP diagnostics. If you cannot run COSP, we would still be delighted to receive simpler, non-COSP, diagnostics.

COSP diagnostics

Consult the COSP warm rain diagnostics table.

Non-COSP diagnostics

To participate, please save one of the following sets of diagnostics:

3D snow and rain mixing ratios
3D snow and rain fluxes
2D snow and rain water paths

The required time frequency is 6-hourly non-accumulated. If this is not feasible for the requested 3D fields, it is possible to implement the warm-rain fraction as an online diagnostic (with monthly-mean 2D output) in the model; please contact Johannes for details.