Warm rain diagnostics

Objective

The warm rain fraction may provide a process-based observational constraint on parameterized precipitation in GCMs, specifically on the cloud lifetime effect (see Johannes's Helsinki AeroCom meeting slides).

We have received base-state warm rain diagnostics from a number of models , but it would be especially useful to see how the warm rain fraction responds to changes in the warm rain (autoconversion/accretion) parameterization.

Required model diagnostics

We would like to piggyback on existing AeroCom experiments (e.g., the multi-model PPE) with as little extra work as possible required.

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 3-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 me for details.

Models participating so far

CAM5 (Contact: Shipeng Zhang, Minghuai Wang)

SPRINTARS (Contact: Takuro Michibata, Toshi Takemura)

IFS (Contact: Amund Søvde, Gunnar Myhre)

ECHAM-HAM (Contact: Johannes Mülmenstädt)

Contact

Johannes Mülmenstädt: johannes.muelmenstaedt@uni-leipzig.de