Assessment of CFSRR medium range forecast skill
Assessment of CFSRR medium range forecast skill
Assessment of CFSRR medium range forecast skill
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Medium Range Forecast<br />
Skill<br />
<strong>CFSRR</strong>, GFS, R2 and R1<br />
Bob Kistler<br />
SAIC<br />
EMC/NCEP<br />
robert.kistler@noaa.gov
Purpose<br />
• Place the <strong>CFSRR</strong> in context<br />
<strong>of</strong> data assimilation and<br />
global <strong>forecast</strong><br />
improvements at NCEP<br />
over the past 2 decades<br />
90<br />
80<br />
500 mb 5 Day Forecasts<br />
NH GFS<br />
SH GFS<br />
NH CDAS/R1<br />
70<br />
• Anomaly Correlation (AC)<br />
• 500 mb<br />
• Annually Averaged<br />
• Hemispheric, NH ad SH<br />
• 1xdaily 120hr <strong>forecast</strong><br />
60<br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004 2009<br />
SH CDAS/R1
Acknowledge other Reanalyses<br />
• Third International Conference on<br />
Reanalysis, Tokyo, Japan, Jan 28-Feb 1,<br />
2008<br />
• MERRA<br />
• ERA-15, ERA-40, ERA-Interim<br />
• NCEP NARR<br />
• 20 th Century<br />
• JRA-25<br />
• Uccellini and Kocin Northeast Snowstorms
Definitions<br />
• GFS – Global Forecast System<br />
• GDAS – Global Data Assimilation System<br />
• 4xdaily 384 hr global <strong>forecast</strong>s (GFS)<br />
• CFS<br />
• R1 – NCEP/NCAR Reanalysis I (1948 ->)<br />
• Kalnay, et.al. 1996<br />
• Kistler, et.al. 2001<br />
• Baseline to GFS<br />
• CDAS - Climate Data Assimilation System<br />
• Continuation <strong>of</strong> R1<br />
• R2 - NCEP/NCAR Reanalysis II (1979 ->)<br />
• Kanamitsu et.al. 2002<br />
• Input to current CFS<br />
• Spectral Statistical Interpolation (SSI)<br />
• GFS to May 2007<br />
• R1 and R2<br />
• Gridded Statistical Interpolation (GSI)<br />
• <strong>CFSRR</strong> and GFS after May 2007<br />
• SSI R1 and R2<br />
• <strong>CFSRR</strong> – Coupled Forecast System (CFS) reanalysis and re<strong>forecast</strong>
Polar Orbiter Satellite Pr<strong>of</strong>iles<br />
• RTOVS (1979-1998)<br />
• TIROS-N, N06,…,N14 (N13 launch failure)<br />
• HIRS2(19) , MSU(4) , SSU(3)-omitted from N10, N12<br />
• ATOVS (1998 -<br />
• N15, N16, N17<br />
• HIRS3(19), AMSUA(15), AMSUB(5)<br />
• N18, N19<br />
• HIRS4(19), AMSUA(15), MHS(5)<br />
• Hyperspectral (thousands <strong>of</strong> channels…)<br />
• AQUA AIRS<br />
• Metop-a IASI<br />
• Retrievals<br />
• Fred Shuman, director NMC circa 1960’s ,<br />
• “Make it look like a rawindsonde”<br />
• GFS to 1998<br />
• R1 and R2, 250 km, 15 pressure levels (same as in 1979)
1990’s Timeline<br />
http://www.emc.ncep.noaa.gov/mmb/data_processing/Satellite_Historical_Documentation.htm<br />
http://www.emc.ncep.noaa.gov/gmb/STATS/html/model_changes.html<br />
• 1991 (Cray YMP)<br />
• R1 planning,<br />
• SSI to ops,<br />
• GFS T126L28<br />
• 1994 R1 began, T62 L28<br />
• 1996 40 years <strong>of</strong> R1, R2 underway<br />
• 1998<br />
• direct assimilation <strong>of</strong> radiances<br />
• First time positive impact <strong>of</strong> sat. data in NH<br />
• 50 years <strong>of</strong> R1 complete
1994, Start <strong>of</strong> R1<br />
• GFS T126L28<br />
500 mb 5 Day Forecasts<br />
• R1 T62L28<br />
• SSI<br />
• RTOVS Retrievals<br />
90<br />
80<br />
70<br />
NH GFS<br />
SH GFS<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994
End R1, 1998<br />
• R1: 1948-1998<br />
500 mb 5 Day Forecasts<br />
• R2: 1979 –<br />
• No Forecasts<br />
• GFS<br />
• 1995 Assimilation<br />
<strong>of</strong> Radiances<br />
• ATOVS debuts<br />
• 1998 assimilation<br />
1b radiances<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994<br />
NH GFS<br />
NH CDAS/Reanl<br />
SH GFS<br />
SH CDAS/Reanl
1998 - 2003<br />
• 2000 T170L42<br />
500 mb 5 Day Forecasts<br />
• 2003 T254L64<br />
• TC relocation<br />
90<br />
• Continual GDAS/SSI<br />
improvements<br />
• 06Z/18Z upgrades<br />
• Longer obs cut<strong>of</strong>f<br />
• Full fcsts<br />
• Physics Upgrades<br />
• Cloud water<br />
• Momentum mixing<br />
• Snow<br />
• AER longwave radiation<br />
• CFS model<br />
• T62L64<br />
• R2 Analysis<br />
• GFS Physics<br />
80<br />
70<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994 1999<br />
NH GFS<br />
SH GFS<br />
NH CDAS/Reanl<br />
SH CDAS/Reanl
CFS re<strong>forecast</strong>s<br />
• R2 analysis<br />
• T62L64<br />
• GFS Physics<br />
90<br />
80<br />
500 mb 5 Day Forecasts<br />
• Improvement over<br />
R1 attributed to:<br />
• 2003 GFS physics<br />
• Systematic error<br />
correction<br />
70<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004 2009<br />
NH CFS R2<br />
NH CDAS/Reanl<br />
SH CFS R2<br />
SH CDAS/Reanl
<strong>CFSRR</strong> Lite<br />
500 mb 5 Day Forecasts<br />
• 2007 GFS system<br />
• Hybrid p-sigma<br />
• Radiance Assimilation<br />
• GSI<br />
• Test entire period 1979-2007<br />
• Each year run independently<br />
• T62L64 Atmos. Only<br />
• Test the obs input<br />
• Test SSU (channel 1-2 only)<br />
90<br />
80<br />
70<br />
60<br />
NH <strong>CFSRR</strong> Lite<br />
SH <strong>CFSRR</strong> Lite<br />
NH CFS R2<br />
SH CFS R2<br />
• Modest gain in NH <strong>skill</strong><br />
• Dramatic gain in SH <strong>skill</strong><br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004
GFS 2007<br />
• May 2005<br />
• T382L64<br />
• 4L NOAH Land Sfc<br />
• Continual GDAS<br />
development<br />
• Observations<br />
• 3DVar<br />
• May 2007<br />
• P-sigma hybrid<br />
• GSI<br />
500 mb 5 Day Forecasts<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004 2009<br />
NH GFS<br />
SH GFS<br />
NH <strong>CFSRR</strong> Lite<br />
SH <strong>CFSRR</strong> Lite
<strong>CFSRR</strong><br />
Full vs Lite<br />
• ATOVS appears to<br />
benefit both SH &<br />
NH<br />
90<br />
500 mb 5 Day Forecasts<br />
NH <strong>CFSRR</strong><br />
• NH post 1994<br />
80<br />
SH <strong>CFSRR</strong><br />
NH <strong>CFSRR</strong> Lite<br />
• Improved<br />
conventional obs<br />
70<br />
SH <strong>CFSRR</strong> Lite<br />
• Raobs<br />
60<br />
• Metar<br />
• ACARS<br />
50<br />
• processing<br />
40<br />
1979 1984 1989 1994 1999 2004 2009
<strong>CFSRR</strong> vs GFS<br />
• <strong>CFSRR</strong> maintained<br />
2000’s GFS <strong>skill</strong><br />
back to 1979<br />
90<br />
500 mb 5 Day Forecasts<br />
NH <strong>CFSRR</strong><br />
• Comparison implies<br />
importance <strong>of</strong><br />
ATOVS to the SH<br />
<strong>skill</strong><br />
80<br />
70<br />
60<br />
SH <strong>CFSRR</strong><br />
NH GFS<br />
SH GFS<br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004 2009
<strong>CFSRR</strong> vs R1<br />
500 mb 5 Day Forecasts<br />
<strong>CFSRR</strong> - R1<br />
20<br />
90<br />
18<br />
NH <strong>CFSRR</strong><br />
80<br />
SH <strong>CFSRR</strong><br />
16<br />
14<br />
SH <strong>CFSRR</strong>-R1<br />
70<br />
NH CDAS/R1<br />
12<br />
NH <strong>CFSRR</strong>-R1<br />
SH CDAS/R1<br />
AC<br />
10<br />
60<br />
8<br />
6<br />
50<br />
4<br />
2<br />
40<br />
1979 1984 1989 1994 1999 2004 2009<br />
0<br />
1979 1984 1989 1994 1999 2004<br />
Year<br />
<strong>CFSRR</strong> – “frozen” system<br />
R1<br />
- “frozen” system + “frozen” ob. Types<br />
Ob. improvement in last decade is evident
• horizontal<br />
resolution matters<br />
in the <strong>medium</strong><br />
<strong>range</strong><br />
• T126 vs T384<br />
<strong>CFSRR</strong> vs GFS<br />
2006-2008
Future ?<br />
• Replace 1948 -1978 R1 ?<br />
• Clues from Uccellini and Kocin,<br />
Northeast Snowstorms<br />
• Details <strong>of</strong> storm systems are improved by<br />
higher resolution<br />
• R1 <strong>forecast</strong> <strong>skill</strong> as measured by the NH day<br />
5 AC may be difficult to exceed<br />
• Limited obs limit <strong>forecast</strong> <strong>skill</strong>
Thank you …<br />
<strong>CFSRR</strong> data available from<br />
http://nomads.ncdc.noaa.gov/NOAAReanalysis/cfsrr
500 mb 5 Day Forecasts<br />
90<br />
NH <strong>CFSRR</strong><br />
NH GFS<br />
80<br />
SH <strong>CFSRR</strong><br />
SH GFS<br />
NH <strong>CFSRR</strong> Lite<br />
SH <strong>CFSRR</strong> Lite<br />
70<br />
NH CFS R2<br />
NH CDAS/Reanl<br />
SH CFS R2<br />
SH CDAS/Reanl<br />
60<br />
50<br />
40<br />
1979 1984 1989 1994 1999 2004 2009
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