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000
NOUS41 KWBC 112100
PNSWSH

Service Change Notice 24-40
National Weather Service Headquarters Silver Spring MD
500 PM EDT Thu Apr 11 2024

To: Subscribers:
 -NOAA Weather Wire Service
 -Emergency Managers Weather Information Network
 -NOAAPort
 Other NWS Partners, Users, and Employees

From: Mike Farrar, Director
 National Centers for Environmental Prediction

Subject: Upgrade of the National Air Quality Forecast Capability
(NAQFC)
 to the Air Quality Modeling (AQM) System Version 7.0,
Effective
 May 14, 2024

Effective on or about Tuesday, May 14, 2024 with the 1200 Coordinated
Universal Time (UTC) cycle, the National Centers for Environmental
Prediction (NCEP) Central Operations (NCO) will be updating the
National
Air Quality Forecast Capability (NAQFC) to the Air Quality Modeling
(AQM)
system version 7.0.

In the event that the implementation date is declared a Critical
Weather
Day (CWD), an Enhanced Caution Event (ECE), or other significant
weather
is occurring or is anticipated to occur, implementation of this
change
will take place at 1200 UTC on the next weekday not declared a CWD
and
when no significant weather is occurring.

Comments/feedback on this upgrade were previously solicited publicly
from
February 28, 2024 through March 28, 2024:

https://www.weather.gov/media/notification/pdf_2023_24/pns24-
14_aqm_v7_product_removal.pdf

AQM version 7.0 will be NCEP’s first regional air quality
prediction
system built upon the Unified Forecast System (UFS) to become
operational.
This system integrates an up-to-date version of NCEP’s atmospheric
model —
based on the Finite-Volume Cubed-Sphere Dynamical Core (FV3) and the
Common Community Physics Package (CCPP) — and an air quality
component
generating atmospheric chemistry predictions through the embedded
U.S.
Environmental Protection Agency (EPA) Community Multiscale Air
Quality
Model (CMAQ) version 5.2.1. The atmospheric and air quality
components are
coupled online for a more accurate representation of the impact of
meteorology on atmospheric chemistry.

AQM version 7.0 is expected to improve representation of wildfire and
meteorological impacts in air quality forecast guidance.



This upgrade includes:
- Upgrading AQM from version 6.1 to version 7.0, transitioning from a
GFS-
CMAQ offline-coupled system to a UFS-based online-coupled
atmosphere-air
quality system embedding CMAQ version 5.2.1

? Replacing individual model domains for CONUS, Alaska, and Hawaii at
about 12km horizontal resolution with a single unified domain at 13km
horizontal resolution

- Increasing the model’s vertical resolution from 35 to 65 levels
and
extending the model’s top from 60 hPa to 0.2 hPa

- Replacing daily Blended Global Biomass Burning Emissions Product
(GBBEPx) inputs with hourly Regional ABI and VIIRS fire Emissions
(RAVE)
data at a high horizontal resolution (0.03 degrees) to improve
diurnal
variation, intensity, and vertical distribution of wildfire emissions

- Replacing the Biogenic Emissions Inventory System (BEIS) with
aerosol
and gaseous emissions estimated using the Model of Emissions of Gases
and
Aerosols from Nature (MEGAN)

- Including soil NOx emissions in springtime (March, April, and May)

? Applying the Kalman Filter Analog (KFAN) bias correction technique
over
the large unified domain to improve near-surface ozone (O3) and fine
particulate matter (PM2.5) predictions. Bias correction will be based
on
expanded AirNow observational data sets.

Products for the three operational domains including CONUS, Alaska,
and
Hawaii are generated from forecasts over the single unified North
American
domain.

The following changes are made to the current operational products
from
this upgrade.
     - Products on the Lambert Conformal 12-km grid (G148) will no
longer
be available on NOMADS.
     - aqm.t{CC}z.pm25.f{HH}.148.grib2
     - aqm.t{CC}z.pm25_bc.f{HH}.148.grib2
     where:
     CC = 00, 06, 12, 18 UTC cycle;
     HH = 01-06 forecast hours for 00 and 18 UTC cycles;
     HH = 01-72 forecast hours for 06 and 12 UTC cycles

    - Hourly averages for the 00Z and 18Z cycles will no longer be
      disseminated to NOMADS.
    - aqm.t{CC}z.ave_1hr_{VARB}.227.grib2
    - aqm.t{CC}z.ave_1hr_{VARB}_bc.227.grib2
    where:
    CC = 00, 18 UTC cycle;
    VARB = pm2.5 or o3 for fine particulate matter and ozone,
    respectively

- The file size of each product may increase due to fewer missing
values


Current model data is available here:

https://nomads.ncep.noaa.gov/pub/data/nccf/com/aqm/prod/
https://ftp.ncep.noaa.gov/data/nccf/com/aqm/prod/
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/aqm/prod/

A real-time parallel feed of the AQMv7.0 has been made available on
NOMADS/FTPPRD web services at:

https://nomads.ncep.noaa.gov/pub/data/nccf/com/aqm/para/
https://ftp.ncep.noaa.gov/data/nccf/com/aqm/para/
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/aqm/para

Please submit comments, questions, or requests on the upgrade to:

Fanglin Yang
Chief, Physics and Dynamics Division
NCEP/Environmental Modeling Center
301-683-3722
Email: fanglin.yang@noaa.gov

For questions regarding the data flow, please contact:

Tony Salemi
NCEP/NCO Implementation and Data Services Branch
College Park, MD
301-683-0567
Email: ncep.pmb.dataflow@noaa.gov

National Service Change Notices are online at:

https://www.weather.gov/notification/