NOUS41 KWBC 301342
PNSWSH
Technical Implementation Notice 12-41
National Weather Service Headquarters
Washington DC
942 AM EDT Thu Aug 30
2012
To:
Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS Partners, Users and Employees
From: Tim
McClung
Chief, Science Plans Branch
Office of Science and Technology
Subject: New NGAC Aerosol Forecast System
Effective September 11, 2012
Effective on or about Tuesday, September 11,
2012, the National Centers for Environmental Prediction (NCEP) will begin to run
and disseminate data from the NOAA Environmental Modeling System Global Forecast System (GFS) Aerosol Component (NGAC).
NGAC is NCEP’s global in-line atmospheric-aerosol module within GFS. The
aerosol component of the NGAC is the Goddard Chemistry Aerosol Radiation and
Transport Model (GOCART). Funded mainly
by NASA’s Earth Science programs, the GOCART model was developed to simulate
common atmospheric aerosols (sulfate, black carbon (BC), organic carbon (OC),
dust, and sea-salt), CO, and sulfur gases.
NGAC Version 1 provides 5-day forecasts of aerosol dust proxies and five
dust particle size ranges listed below, once per day for the 0000 UTC cycle.
The NGAC output will be available in GRIB2 format on a 1x1 degree output grid,
with output available for 00 to 120 hours, with output every
http://www.ftp.ncep.noaa.gov/pub/data/nccf/com/ngac
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/ngac
Output files and their contents include:
(1) ngac.t00z.a2df$HR, where HR=00, 03,
...,120:
2D products including
AER_OPT_DEP_at550: dust aerosol optical depth at 550nm (dimensionless)
CR_AER_SFC_MASS_CON: coarse mode surface mass concentration (kg/m3)
FN_AER_SFC_MASS_CON: fine mode surface mass concentration (kg/m3)
CR_AER_COL_MASS_DEN: coarse mode column mass density (kg/m2)
FN_AER_COL_MASS_DEN: fine mode column mass density kg/m2
DUST_EMISSION_FLUX: dust emission fluxes (kg/m2/sec)
DUST_SEDIMENTATION_FLUX: dust sedimentation fluxes (kg/m2/sec)
DUST_DRY_DEPOSITION_FLUX: dust dry deposition fluxes (kg/m2/sec)
DUST_WET_DEPOSITION_FLUX: dust wet deposition fluxes (kg/m2/sec)
(2) ngac.t00z.a3df$HR, where HR=00, 03, ...,
120:
3D products at model levels including
PRES: pressure (Pa)
RH: relative humidity (%)
TEMP: temperature (K)
DUST1: dust bin1 (0.1-1 micron) mixing ratio (kg/kg)
DUST2: dust bin2 (1-1.8 micron) mixing ratio (kg/kg)
DUST3: dust bin3 (1.8-3 micron) mixing ratio (kg/kg)
DUST4: dust bin4 (3-6 micron) mixing ratio (kg/kg)
DUST5: dust bin5 (6-10 micron) mixing ratio (kg/kg)
(3) ngac.t00z.aod_$NM, where NM=11p1um, 1p63um,
340nm, 440nm, 550nm, 660nm, 860nm:
Aerosol optical depth at specified wavelengths (11.1, 1.63, 0.34, 0.44,
0.55, 0.66, and 0.86 micron)
A consistent parallel feed of data is
currently available on the NCEP server via the following URL's:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/ngac/para
or
http://www.ftp.ncep.noaa.gov/data/nccf/com/ngac/para
Users please note that NGAC products are encoded in GRIB2 using a
relatively-new GRIB template. Users
should download the latest versions of wgrib2 and the other NCEP GRIB utilities
to use the NGAC output products. Many of
these utilities were updated on July 17, 2012. Users can access the NCEP GRIB utilities from this URL:
http://www.nco.ncep.noaa.gov/pmb/codes/nwprod/util/exec
A Website containing more information about NCEP's dust product can be
found at:
http://www.emc.ncep.noaa.gov/gmb/sarah/NGAC/html/realtime.ngac.html
For questions regarding the scientific
content of the NGAC model please contact:
Sarah Lu
NCEP/EMC
College Park, Maryland 20740
301-683-3733
For questions regarding the dataflow
aspects of these data
sets please contact:
Rebecca Cosgrove
NCEP/NCO Dataflow Team
College Park , Maryland 20740
301-683-0567
ncep.list.pmb-dataflow@noaa.gov
NWS National Technical Implementation
Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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