[Wrf-users] NMM binary cloud cover percentage
preuter64 at yahoo.de
Fri Mar 27 08:44:02 MDT 2009
Dear WRF users,
I succesfully run NMM forecasts with the WPP postprocessor for central
europe, and I am pretty happy about the wind output results compared
to the real-world.
However, I have some concerns using the cloud cover output.
Actually, it appears to output very often 0% cloud cover or 100% cloud
cover, and very rarely something in between (actually it does it only
at the spatial borders of some cloudy regions). As a consequence, the
cloud forecast is not reliable at all (compared to directly usin GFS,
for example), and even the 0% or 100% are not reliable, sometimes it
shows 100% although it's sunny and vice versa.
This happens for all four types of cloud covers, low, middle, high,
and total percentage.
For the physics, I use the following entries in the physics section
(pretty standard I guess) :
mp_physics = 5, 5, 5,
ra_lw_physics = 99, 99, 99,
ra_sw_physics = 99, 99, 99,
nrads = 105, 315, 315,
nradl = 105, 315, 315,
co2tf = 1,
sf_sfclay_physics = 2, 2, 2,
sf_surface_physics = 99, 99, 99,
bl_pbl_physics = 2, 2, 2,
nphs = 6, 18, 18,
cu_physics = 2,
ncnvc = 6,
tprec = 1,
theat = 6,
tclod = 1,
My input data is 6 hourly GFS 0.5 degree data (54km), and I run a
nested grid at 15 and then 5 km horizontal resolution, on a
I would appreciate any comment on this topic.
Thanks in advance
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