Difference between revisions of "Overview of GMAO met data products"

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(→‎GEOS-1 features)
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{| border=1 cellspacing=0 cellpadding=5  
 
{| border=1 cellspacing=0 cellpadding=5  
 
|-
 
|-
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|'''Assimilation GCM used'''
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|''Assimilation GCM used:''
 
|NASA/GSFC GEOS1 GCM
 
|NASA/GSFC GEOS1 GCM
 
|-valign="top"
 
|-valign="top"
−
|'''Native horizontal grid:'''
+
|''Native horizontal grid:''
 
|[http://acmg.seas.harvard.edu/geos/doc/man/appendix_2.html#A2.3 2° x 2.5°]  
 
|[http://acmg.seas.harvard.edu/geos/doc/man/appendix_2.html#A2.3 2° x 2.5°]  
 
|-valign="top"
 
|-valign="top"
−
|'''Native vertical grid:'''
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|''Native vertical grid:''
 
|20 pure-sigma layers, model top at 10 hPa
 
|20 pure-sigma layers, model top at 10 hPa
 
|-valign="top"
 
|-valign="top"
−
|'''Native file format:'''
+
|''Native file format:''
 
|NASA PHOENIX format (binary Fortran unformatted)
 
|NASA PHOENIX format (binary Fortran unformatted)
 
|-valign="top"
 
|-valign="top"
−
|'''Temporal coverage:'''
+
|''Temporal coverage:''
 
|1985-1995
 
|1985-1995
 
|-valign="top"
 
|-valign="top"
−
|'''We regridded to:'''
+
|''We regridded to:''
 
|[http://acmg.seas.harvard.edu/geos/doc/man/appendix_2.html#A2.2 4 x 5]; 20 pure-sigma layers
 
|[http://acmg.seas.harvard.edu/geos/doc/man/appendix_2.html#A2.2 4 x 5]; 20 pure-sigma layers
 
|-valign="top"
 
|-valign="top"
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|'''Strengths:'''
+
|''Strengths:''
 
|
 
|
 
*Long temporal coverage (10 years)
 
*Long temporal coverage (10 years)
 
|-valign="top"
 
|-valign="top"
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|'''Weaknesses:'''
+
|''Weaknesses:''
 
|
 
|
 
*Very low model top (10 hPa)
 
*Very low model top (10 hPa)

Revision as of 20:46, 27 July 2010

GMAO data products used by GEOS-Chem

  GEOS-1 GEOS-STRAT GEOS-3 GEOS-4 GEOS-5 MERRA
Native # of levels 20 sigma 26 sigma 48 sigma 55 hybrid 72 hybrid 72 hybrid
Native grid 2° x 2.5° 2 x 2.5 1° x 1° 1° x 1.25° 0.5° x 0.666° 0.5 x 0.666 and
1 x 1.25
Native file format Binary Binary HDF4-EOS HDF4-EOS HDF4-EOS HDF4-EOS
Regridded to 2° x 2.5°
4 x 5 		2° x 2.5°
4° x 5° 		1° x 1° nested
°2 x 2.5°
4° x 5&degl 		2° x 2.5°
4° x 5° 		0.5° x 0.666° nested
2° x 2.5°
4° x 5° 		4 x 5
Temporal coverage 1985 - 1995 1996 - 1998 2000 - 2002 1985 - 2007 2004 - present 1979 - 2010

NOTES:

  1. GEOS-1 and GEOS-STRAT are now obsolete and no longer supported by GEOS-Chem
  2. GEOS-3 is still supported but we recommend users to migrate to GEOS-4 or GEOS-5.
  3. MERRA data will be made available at 4 x 5 resolution in the near future. MERRA is a long-term reanalysis done with version GEOS-5.2.0.

--Bob Y. 16:24, 27 July 2010 (EDT)

GEOS-1 and GEOS-STRAT

GEOS-1 was the first GMAO met field data product compatible with GEOS-Chem. GEOS-STRAT was a continuation of GEOS-1, but with a finer vertical grid.

GEOS-1 features

Assimilation GCM used: NASA/GSFC GEOS1 GCM
Native horizontal grid: 2° x 2.5°
Native vertical grid: 20 pure-sigma layers, model top at 10 hPa
Native file format: NASA PHOENIX format (binary Fortran unformatted)
Temporal coverage: 1985-1995
We regridded to: 4 x 5; 20 pure-sigma layers
Strengths:
  • Long temporal coverage (10 years)
Weaknesses:
  • Very low model top (10 hPa)
  • Strat-trop exchange was too fast by 2-3X

GEOS-STRAT features

Assimilation GCM used NASA/GSFC GEOS1 GCM
Native horizontal grid: 2° x 2.5°
Native vertical grid: 46 pure-sigma layers, model top at 0.1 hPa
Native file format: NASA PHOENIX format (binary Fortran unformatted)
Temporal coverage: 1996-1997 (some 1998)
We regridded to: 4 x 5; 26 pure-sigma layers
Strengths:
  • Higher model top, better stratospheric representation
Weaknesses:
  • Vertical grid did not correspond to GEOS–1
  • STE still too fast by 2-3X
  • Surface data had a 6-hr temporal resolution, we had to interpolate to a 3-hr temporal resolution ourselves

--Bob Y. 16:43, 27 July 2010 (EDT)

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