NOUS41 KWBC 031250

PNSWSH

 

Service Change Notice 17-10

National Weather Service Headquarters Silver Spring, MD

850 AM EST Fri Feb 3 2017

 

To:        Subscribers:

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network

           -NOAAPORT

           Other NWS Partners, Users and Employees

 

From:      Dave Myrick

           NWS Office of Science and Technology Integration

 

Subject:   NGAC Aerosol Forecast System Upgrade

           Effective March 7, 2017

 

Effective on or about March 7, 2017, starting with the 1200

Coordinated Universal Time (UTC) cycle, the National Centers

for Environmental Prediction (NCEP) will begin to run and

disseminate data from the NEMS GFS Aerosol Component Version 2

system (NGACv2).

 

NGAC is a global inline atmospheric-aerosol module within the

NOAA Environmental Modeling System (NEMS) Global Forecast

System (GFS). The aerosol component of the NGAC is the Goddard

Chemistry Aerosol Radiation and Transport Model (GOCART).

 

The scope of this upgrade includes:

- Extending aerosol species from dust only to multiple species

including dust, sea salt, sulfate, organic carbon and black

carbon aerosols; the extension will provide a more complete

global aerosol forecast using the near real time Global Blended

Biomass Burning Emissions Product (GBBEPx)

- Updating meteorological model physics including the Rapid

Radiative Transfer Model (RRTM) with Monte Carlo Independent

Column Approximation (McICA) radiation package, Eddy-

Diffusivity

Mass-Flux (EDMF) Planetary Boundary Layer (PBL) scheme and land

surface updates on canopy height scheme, soil moisture nudge

and roughness length

- Fixing bugs such as AOD computation, and error message in MPI

quit

 

Emission sources/techniques used for new species are:

 

 * Source for sulfate: daily biomass burning emissions from

NESDIS GBBEPx and biofuel and fossil fuel emissions from

Aerosol Comparisons between observations and models (AeroCom)

anthropogenic emissions. Dimethylsulfide (DMS) source is a

climatology of oceanic DMS concentrations (Chin et al. J.

Atmos. Sci., 2002).

 * Sources for carbonaceous aerosols: daily biomass burning

emissions from NESDIS GBBEPx, biofuel and fossil fuel

climatology from AeroCom anthropogenic emissions and

climatology Emission Database for Global Atmospheric Research

(EDGAR) based ship emissions. Organic carbon also has Terpene

emission.

 * Emission techniques for sea salt: NGACv2 has 5 size sea salt

bins (dry radius range: 0.03-10micron); the emission is a

function of particle size and surface wind speed (Gong S.,

Global Biogeochem. Cy. 2003)

- Model will be run twice daily: 00Z and a new 12Z cycle

- File  names will be standardized

- New fields will be added in all output files (listed below)

 

The changes will provide the following benefits/impacts:

- Guidance on long range aerosol transport impacting the United

States

- Dynamic aerosol lateral boundary conditions to regional air

quality model

- Multi-species aerosol forecasts to end users for applications

such as sea surface temperature retrieval and UV index

forecast.

 

 

The changes to the files names are as follows:

 

Where: HHH=00 to 120 in 3hr increments and CC=00, 12(new)

 

        Old                          New

  ngac.tCCz.a2dfHHH    ->  ngac.tCCz.a2dfHHH.grib2

  ngac.tCCz.a3dfHHH    ->  ngac.tCCz.a3dfHHH.grib2

  ngac.tCCz.aod_340nm  ->  ngac.tCCz.aod_340nm.grib2

  ngac.tCCz.aod_440nm  ->  ngac.tCCz.aod_440nm.grib2

  ngac.tCCz.aod_550nm  ->  ngac.tCCz.aod_550nm.grib2

  ngac.tCCz.aod_660nm  ->  ngac.tCCz.aod_660nm.grib2

  ngac.tCCz.aod_860nm  ->  ngac.tCCz.aod_860nm.grib2

  ngac.tCCz.aod_1p63um ->  ngac.tCCz.aod_1p63um.grib2

  ngac.tCCz.aod_11p1um ->  ngac.tCCz.aod_11p1um.grib2

 

The output files will now include these new fields:

 

(1) ngac.tCCz.a2dfHHH.grib2, where HHH=00,03,...,120 &

CC=00,12:

 

New fields:

 

ASYSFK: Asymmetry Factor at 340 nm from total aerosols

[Numeric]

SSALBK: Single Scattering Albedo at 340 nm from total aerosols

[Numeric]

AOTK: Aerosol Optical Thickness at 550 nm from total aerosols

[Numeric]

AOTK: Aerosol Optical Thickness at 550 nm from sea salt aerosol

[Numeric]

AOTK: Aerosol Optical Thickness at 550 nm from black carbon dry

aerosol [Numeric]

AOTK: Aerosol Optical Thickness at 550 nm from particulate

organic carbon dry aerosol [Numeric]

AOTK: Aerosol Optical Thickness at 550 nm from sulphate dry

aerosol [Numeric]

DUST_SCAVENGING_FLUX: dust wet Deposition by Convective

Precipitation Flux fluxes (kg/m2/sec)

SEASALT_EMISSION_FLUX: sea salt emission mass flux (kg/m2/sec)

SEASALT_SEDIMENTATION_FLUX: sea salt sedimentation mass flux

(kg/m2/sec)

SEASALT_DRY_DEPOSITION_FLUX: sea salt dry deposition mass flux

(kg/m2/sec)

SEASALT_WET_DEPOSITION_FLUX: sea salt wet deposition by large

scale precipitation mass flux (kg/m2/sec)

SEASALT_SCAVENGING_FLUX: sea salt wet deposition by convective

precipitation mass flux (kg/m2/sec)

BC_EMISSION_FLUX: black carbon emission mass flux (kg/m2/sec)

BC_SEDIMENTATION_FLUX: black carbon sedimentation mass flux

(kg/m2/sec)

BC_DRY_DEPOSITION_FLUX: black carbon dry deposition mass flux

(kg/m2/sec)

BC_WET_DEPOSITION_FLUX: black carbon wet deposition by large

scale precipitation mass flux (kg/m2/sec)

BC_SCAVENGING_FLUX: black carbon wet deposition by convective

precipitation mass flux (kg/m2/sec)

OC_EMISSION_FLUX: particulate organic carbon emission mass flux

(kg/m2/sec)

OC_SEDIMENTATION_FLUX: particulate organic carbon sedimentation

mass flux (kg/m2/sec)

OC_DRY_DEPOSITION_FLUX: particulate organic carbon dry

deposition mass flux (kg/m2/sec)

OC_WET_DEPOSITION_FLUX: particulate organic carbon wet

deposition by large scale precipitation mass flux (kg/m2/sec)

OC_SCAVENGING_FLUX: particulate organic carbon wet deposition

by convective precipitation mass flux (kg/m2/sec)

 

(2) ngac.tCCz.a3dfHHH.grib2, where HHH=00,03,...,120 &

CC=00,12:

 

New fields:

 

SEASALT1: sea salt bin1 (diameter: 0.06-0.2 micron) mixing

ratio (kg/kg)

SEASALT2: sea salt bin2 (diameter: 0.2-1 micron) mixing ratio

(kg/kg)

SEASALT3: sea salt bin3 (diameter: 1-3 micron) mixing ratio

(kg/kg)

SEASALT4: sea salt bin4 (diameter: 3-10 micron) mixing ratio

(kg/kg)

SEASALT5: sea salt bin5 (diameter: 10-20 micron) mixing ratio

(kg/kg)

BC1: black carbon hydrophobic dry (median diameter: 0.0236

micron), mixing ratio (kg/kg)

BC2: black carbon hydrophilic dry (median diameter: 0.0236

micron), mixing ratio (kg/kg)

OC1: particulate organic carbon hydrophobic dry (median

diameter: 0.0424 micron), mixing ratio (kg/kg)

OC2: particulate organic carbon hydrophilic dry (median

diameter: 0.0424 micron), mixing ratio (kg/kg)

SO4: sulphate dry (median diameter: 0.139 micron), mixing ratio

(kg/kg)

 

(3) ngac.tCCz.aod_$NM.grib2, where NM=11p1um, 1p63um, 340nm,

440nm, 550nm, 660nm, 860nm & CC=00,12:

Total aerosol optical depth at specified wavelengths (11.1,

1.63, 0.34, 0.44, 0.55, 0.66, and 0.86 micron)

 

Note: NGACv1 total aerosol optical depth is from dust only.

NGACv2 total aerosol optical depth is from multiple species

including dust, sea salt, sulphate, black carbon and

particulate organic carbon

 

New fields:

ngac.t00z.aod_550nm.grib2 file also contains aerosol optical

depth at 550nm from each species: dust, sea salt, sulfate,

organic carbon and black carbon.

 

 

The NGAC output will continue to be disseminated via NCEP's

ftp/http server at the following locations:

  http://www.nomads.ncep.noaa.gov/pub/data/nccf/com/ngac/prod

  http://www.ftp.ncep.noaa.gov/data/nccf/com/ngac/prod

  ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/ngac/prod

 

Web graphics will remain available at:

  http://www.emc.ncep.noaa.gov/gmb/NGAC/html/realtime.ngac.html

 

A consistent parallel feed of data will be available on the

NCEP server via the following URL:

  http://para.nomads.ncep.noaa.gov

 

NGAC products are encoded in GRIB2. The NCEP grib2 table is

updated to include the definition of new aerosol types. Users

should download the latest versions of wgrib2 and the other

NCEP GRIB utilities to use the NGAC output products. 

 

A website containing retrospective run results from NGACv2 for

the period of Apr2015-Feb2016 is online at:

  http://www.emc.ncep.noaa.gov/gmb/NGAC/V2/

 

Questions, comments or requests regarding this implementation

should be directed to the contacts below. We will review

feedback and decide whether to proceed.

 

For questions regarding the scientific content of the NGAC

model, please contact:

 

Jun Wang

NCEP/EMC

College Park, Maryland 20740

301-683-3811

jun.wang@noaa.gov

 

For questions regarding the dataflow aspects of these data

sets, please contact:

 

Carissa Klemmer

NCEP Dataflow Team Lead

College Park, Maryland 20740

301-683-0567

ncep.list.pmb-dataflow@noaa.gov

 

NWS Service Change Notices are online at:

 

    http://www.nws.noaa.gov/os/notif.htm

 

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