Wind errors in the GFS

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Wind errors in the GFS Glenn.White_at_noaa.gov
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GFS .033 behind ECMWF, .006 behind Met Office
Fang-Lin Yang
GFS .019 ahead of ECMWF
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GFS .051 behind ECMWF, .037 behind Met Office
Fang-Lin Yang
GFS .078 behind ECMWF
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CPC
GFS slightly better than ECMWF GFS 6-10 day
forecasts explain 50 of variance
CPC
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GFS poor precip forecasts, large bias
MMB
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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
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Note increase in number Of observations
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Improvement has leveled off Last 2 years
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Little improvement last 5 years
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GSI improved agreement with analyses, not with
raobs
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GFS analyses Closer to rawinsondes
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ECMWF forecasts Closer to Rawinsondes
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GFS day 1 and day2 problem
GFS Day 1 problem
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In NH extratropics, fall behind ECMWF first 24
hours In tropics fall behind ECMWF day 2 Wind
errors not just a tropical problem.
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Zonal mean RMS difference in wind analyses
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Analyses most different at equator Above 700
hPa GFS most like ECMWF Most different from
FNMOC EC more similar to Met Office Than GFS
except above 150hPa at equator
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RMS difference in wind analyses at equator
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Biggest differences in analyses 200 hPa and
above And in ePacific 800-400 hPa
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GFS stronger trades than other centers
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GFS more variability in forecasts than other
centers FNMOC less variability Transient eddy
kinetic energy (1/2(u2v2))
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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
centers GFS more variability in
forecasts Initially GFS error grows more slowly
near equator than other centers, more rapidly
than other centers in midlatitudes.