I ran the UCLA large eddy simulation (LES) model to generate a wide
variety of marine boundary layer cloud structure for developing cloud
remote sensing methods using 3D radiative transfer. Bjorn Stevens, the
author of the UCLA LES model, helped me with running the model. I
initialed the LES model with atmospheric profiles from random columns at
specific times from the ECMWF ERA-Interim reanalysis.
Description of LES model:
Description of the simulation procedure:
- Data source: ERA-Interim reanalysis; 1.5o x 25 mb x 6
hrs resolution; surface and pressure level parameters from 600 to 1000
- Location: North east Pacific: 0N to 45N, 150W to 105W, oceanic columns
- Times: 18Z on 2007-05-21, 2007-06-21, 2007-07-22, 2007-08-22, 2007-09-23.
- ERA column selection:
- CAPE: 0 to 500 J/kg
- BL max cloud fraction: 0.10 to 1.00
- Mid-layer max cloud fraction: 0.0 to 0.01
- Simulation time: 8:00 to 14:00 local time
- Horizontal grid: 160x160 at 50 m spacing
- Domain top: 500 m above first ERA level with potential temperature
more than 10 K above that at 1000 mb.
- Vertical grid: Variable grid; 40 m default spacing; 20 m spacing
at surface; 10 m spacing around imposed jumps or 20 m spacing around the
max dtheta/dz ERA layer if dtheta/dz>10 K/km; 400 m wide high-resolution
region (75% above jump) for imposed jumps, otherwise 250 m wide region
centered on layer.
- Vertical jump in sounding: 10 m wide jump imposed at ERA boundary
layer height if the two ERA layer (50 mb) potential temperature
difference is > 5 K and the max BL cloud fraction > 0.80.
- Large scale forcing: zero temperature and total water advection;
large scale vertical velocity is from ERA.
- Surface fluxes: LES water surface parameterization
- Sea surface temperature: Initial SST set ERA SST; SST changes
linearly with time according to ERA SST gradient and mean wind speed
for a Lagragian-type simulation.
- Microphysics: fixed cloud droplet concentration from random CCN
with an exponential distribution between 40 and 400 cm-3; two-moment
drizzle/rain bulk microsphysics scheme (see Stevens and Seifert 2008).
- Radiation: Fu/McISA independent column radiation code
(Pincus and Stevens, 2009) , randomly sampled 1/3 of the time for speed up,
for longwave and shortwave radiative transfer.
- Subgrid scale mixing: Smagorinsky closure; turned off SGS mixing
Click on image for a web page with graphs for each set of five simulations.
At the end of each web page below there are links to netcdf files with
the 3D fields of liquid water content. These files may be read with les2lwc.f90 .
Simulations: era0521nh1 to era0521nh5
Simulations: era0521nh6 to era0521nh10
Simulations: era0621nh1 to era0621nh5
Simulations: era0621nh6 to era0621nh10
Simulations: era0722nh1 to era0722nh5
Simulations: era0722nh6 to era0722nh10
Simulations: era0822nh1 to era0822nh5
Simulations: era0822nh6 to era0822nh10
Simulations: era0923nh1 to era0923nh5
Simulations: era0923nh6 to era0923nh10
Simulations: era0521nh11 to era0521nh15
Simulations: era0521nh16 to era0521nh20
Simulations: era0621nh11 to era0621nh15
Simulations: era0621nh16 to era0621nh20
Simulations: era0722nh11 to era0722nh15
Simulations: era0722nh16 to era0722nh20
Simulations: era0822nh11 to era0822nh15
Simulations: era0822nh16 to era0822nh20
Simulations: era0923nh11 to era0923nh15
Simulations: era0923nh16 to era0923nh20
Simulations: era0521nh21 to era0521nh25
Simulations: era0621nh21 to era0621nh25
Simulations: era0722nh21 to era0722nh25
Simulations: era0822nh21 to era0822nh25
Simulations: era0923nh21 to era0923nh25
Simulations: era0521nh26 to era0521nh30
Simulations: era0621nh26 to era0621nh30
Simulations: era0722nh26 to era0722nh30
Simulations: era0822nh26 to era0822nh30
Simulations: era0923nh26 to era0923nh30
Simulations: era0521nh31 to era0521nh35
Simulations: era0621nh31 to era0621nh35
Simulations: era0722nh31 to era0722nh35
Simulations: era0822nh31 to era0822nh35
Simulations: era0923nh31 to era0923nh35
Simulations: era0521nh36 to era0521nh40
Simulations: era0621nh36 to era0621nh40
Simulations: era0722nh36 to era0722nh40
Simulations: era0822nh36 to era0822nh40
Simulations: era0923nh36 to era0923nh40