wind errors in the gfs [email protected] tommy gun's valentine's massacre dinner show -...
Post on 22-Dec-2015
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Wind errors in the GFS
Tommy Gun's Valentine's Massacre Dinner Show - February 14 and 17 –
Forget dat romantic Valentine's Day and celebrate it wit a bang!
Join us in our annual re-enactment of the St. Valentine's Day Massacre
after our dinner show, in honor of Valentine's Day - Chicago-style.
Fang-Lin Yang
GFS .033 behind ECMWF, .006 behind Met Office
GFS .019 ahead of ECMWF
Fang-Lin Yang
GFS .051 behind ECMWF, .037 behind Met Office
GFS .078 behind ECMWF
GFS slightly better than ECMWF;GFS 6-10 day forecasts explain 50% of variance
CPC
CPC
GFS poor precip forecasts, large bias
MMB
Jan. 2000 T170 L42
May 2001 cloud liquid water, momentum mixing, stonger QC AMSU
Oct. 2002 T254 L64, analysis changes
May 2005 T382 L64, increased mountain blocking, decreased vertical diffusion
May 2007 GSI, hybrid vertical coordinate
Note increase in numberOf observations
Improvement has leveled offLast 2 years
Little improvement last 5 years
GSI improved agreement with analyses, not with raobs
GFS analysesCloser to rawinsondes
ECMWFforecastsCloser toRawinsondes
GFS Day 1 problemGFS day 1 and day2 problem
In NH extratropics, fall behind ECMWF first 24 hoursIn tropics fall behind ECMWF day 2
Wind errors not just a tropical problem.
Zonal mean RMS difference in wind analyses
Analyses most different at equatorAbove 700 hPaGFS most like ECMWFMost different from FNMOC
EC more similar to Met Office Than GFS except above 150hPa atequator
RMS difference in wind analyses at equator
Biggest differences in analyses 200 hPa and aboveAnd in ePacific 800-400 hPa
GFS stronger trades than other centers
GFS more variability in forecasts than other centersFNMOC less variability
Transient eddy kinetic energy (1/2(u’2+v’2))
GFS tends to have larger rms wind errors than ECMWF, Met Office
Not just a tropical problem
Analysis differences quite large near equator
GFS stronger trade winds western hemisphere
FNMOC less variability than other centersGFS more variability in forecasts
Initially GFS error grows more slowly near equator than other centers, more rapidly than other centers in midlatitudes.