DYCOMS II SCM case

Introduction:

The aim of the DYCOMS II SCM comparison is to translate the DYCOMS II LES case for SCM application. We shall then benefit from the comparison of SCM results directly to LES results and DYCOMS observations.

SCM case description:

1. original DYCOMS LES setup plus ...

2. Bjorn's adjustments:
   1) free-troposphere cooler by 1.5K (see latest profiles)
   2) u* fixed at 0.25 (if possible)
   3) inversion cooling at levels above the height of the qt=8g/kg contour,
   where I interpolate.

3. all nocturnal, all simplified radiation

4. initial state: use profile given by Bjorn and modified by Martin
   * no moist layer above PBL
   * profiles provide for initial liquid water and cloud fraction should
   be set to 100% where ql>0 (Tiedtke e.g. would otherwise not produce
   any cloud)

5. simulations:

   (A) 6h with fixed surface fluxes
   (B) long (to equilibrium, but at least 48h) with fixed SST

   sensitivities:
   (R1) dt=5s, dz=10m
   (R2) dt=1800s, dz=operational
   (e.g. ECMWF: 2804,2409,2046,1715,1418,1153,921,
   723,553,410,292,198,126,73,35,10m)

   (C1) shallow convection parameterization on (operational)
   (C2) shallow convection parameterization off

   (P1) precipiation on
   (P2) precipiation off

   (On) other parameterization choices are welcome

6. output:
   - format: netcdf as LES (or ncgen/ncdump ascii format)
   - file names: e.g. A.R1.C1.P1.O1.koehler.nc
   - data:
   • set T: timeseries - at every time step (1,2,4,6,7,12,13,14)
   • set A: mean state - hourly average (1-7, add cloud fraction [%])
   • set C: fluxes - hourly average (1,2, radiative flux only)

   - send to Ping Zhu (pzhu@atmos.washington.edu)

7. deadline: 15 December

For some more details please refer to my initial results.

Initial email discussion

Related documents

original initial state profiles from Bjorn

new profiles updated by Martin (see comments here)

Latest profiles updated to remove moist layer above PBL (use these!).

Participants and their initial results (following links below):

Adrian Lock <Adrian.Lock@ec.gc.ca>

Andreas Chlond <chlond@dkrz.de>

Anning Cheng <a.cheng@larc.nasa.gov>

Luo Yali <yali@met.utah.edu>

Martin Köhler <martin.koehler@ecmwf.int>

Phil Austin <paustin@eos.ubc.ca>

Pier Siebesma <siebesma@knmi.nl>

Ping Zhu <pzhu@atmos.washington.edu>

Surabi Menon <smenon@lbl.gov>

Steve Klein <stephen.klein@noaa.gov>

Observers:

Bjorn Stevens <bstevens@atmos.ucla.edu>

Chris Bretherton <breth@atmos.washington.edu>