List of MERRA-2 met fields

MERRA2 is a new NASA/GMAO reanalysis product. It has a horizontal resolution of 0.5° lat x 0.625° lon x 72 vertical levels. The horizontal resolution is 2x coarser than the GMAO "forward processing" product (which we refer to as GEOS-FP). But MERRA2 uses the identical vertical grid as the GEOS-5#GEOS-5, MERRA, and the "GEOS-FP" data products used by GEOS-Chem.

NOTE: GEOS-Chem only uses a subset of the entire MERRA2 data archive. On this page we list the MERRA2 met fields that we archive for use with GEOS-Chem.

As of August 2015, we have not finalized this list of MERRA2 met fields that we will archive for GEOS-Chem. If your research requires additional fields not listed below, please contact the GEOS-Chem Support Team.

Constant fields

1. These data will be timestamped 2011/01/01 at 00:00 GMT for convenience.
2. These are time-invariant constant fields, which will have the following filenames:
   • MERRA2.20110101.CN.05x0625.CH.nc  (Native resolution nested CH grid)
   • MERRA2.20110101.CN.05x0625.EU.nc  (Native resolution nested EU grid)
   • MERRA2.20110101.CN.05x0625.NA.nc  (Native resolution nested NA grid)
   • MERRA2.20110101.CN.05x0625.NA.nc  (Native resolution nested SE grid)
   • MERRA2.20110101.CN.2x25.nc  (2° x 2.5° global grid)
   • MERRA2.20110101.CN.4x5.nc  (4° x 5° global grid)
3. The Collection indicates the MERRA2 raw data files in which each field may be found.
4. One MERRA2 raw data file is created for each day of data.
   • Therefore, the CN data fields listed below will be contained in a single MERRA2 raw data file.

Field	Units	Collection	Description	Notes	Where used in GEOS-Chem?
FRLAKE	1	const_2d_asm_Nx	Fraction of lake type in grid box		CH4 simulation, diagnostics
FRLAND	1	const_2d_asm_Nx	Fraction of land type in grid box		Chemistry Hg simulation CH4 simulation PBL mixing
FRLANDIC(E)	1	const_2d_asm_Nx	Fraction of land ice type in grid box	The original name in the GEOS-FP raw data files is FRLANDICE. We shorten this to FRLANDIC for GEOS-Chem. GEOS-Chem requires 8-character met field names.	Hg simulation CH4 simulation PBL mixing
FROCEAN	1	const_2d_asm_Nx	Fraction of ocean in grid box		Chemistry Hg simulation CH4 simulation Emissions
PHIS	m2 s-2	const_2d_asm_Nx	Surface geopotential		Kept for diagnostics

--Bob Y. (talk) 15:48, 3 August 2015 (UTC)