349
NOUS41 KWBC 282015
PNSWSH
PUBLIC INFORMATION STATEMENT 26-07
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD
315 PM EST WED JAN 28 2026
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS, USERS AND EMPLOYEES
FROM: DR. FANGLIN YANG
CHIEF, PHYSICS AND DYNAMICS DIVISION
NCEP/ENVIRONMENTAL MODELING CENTER
SUBJECT: SOLICITING COMMENTS THROUGH FEBRUARY 28, 2026 ON THE
PROPOSED REPLACEMENT OF GEFS AEROSOL PRODUCTS WITH THE GLOBAL
CHEMISTRY AND AEROSOL FORECAST SYSTEM (GCAFS) VERSION 1.0
THE ENVIRONMENTAL MODELING CENTER (EMC) IS SOLICITING COMMENTS
THROUGH FEBRUARY 28, 2026 ON THE PROPOSED IMPLEMENTATION OF THE
GLOBAL CHEMISTRY AND AEROSOL FORECAST SYSTEM (GCAFS) VERSION 1.0
WITH THE PURPOSE OF IMPROVING PREDICTIONS OF DUST, SEA SALT,
SMOKE FROM WILDFIRES, AND OTHER PARTICLES IN THE ATMOSPHERE THAT
CAN IMPACT VISIBILITY OR HUMAN HEALTH REPLACING THE CURRENT
CAPABILITY OF THE GLOBAL ENSEMBLE FORECAST SYSTEM (GEFS).
ALONGSIDE GCAFS VERSION 1.0 COMES THE GLOBAL CONSTITUENT DATA
ASSIMILATION SYSTEM (GCDAS) WHICH PROVIDES ANALYSES OF AEROSOL
SPECIES TO INITIALIZE THE GCAFS FORECASTS USING THE NEXT-
GENERATION ASSIMILATION SOFTWARE, THE JOINT EFFORT FOR DATA
ASSIMILATION INTEGRATION (JEDI). GCAFS V1.0 WILL INSTEAD
PROVIDE A 5-DAY GCAFS FORECAST WITH 3-HOURLY OUTPUT FOR THE 00
AND 12 UTC CYCLES. A NEW ANALYSIS, THE GLOBAL CONSTITUENT DATA
ASSIMILATION SYSTEM (GCDAS), WILL PROVIDE ANALYSES OF AEROSOL
SPECIES AT THE 00, 06, 12, AND 18 UTC CYCLES TO INITIALIZE THE
GCAFS FORECASTS, PROVIDING PRODUCTS VALID AT INITIALIZATION TIME
ONLY.
THE IMPLEMENTATION OF GCAFS V1.0 IS INTENDED TO SEPARATE AND
TRANSITION THE EXISTING AEROSOL MODELING CAPABILITY FROM THE
CURRENT OPERATIONAL GLOBAL ENSEMBLE FORECAST SYSTEM (GEFS)
VERSION 12, WHILE MAINTAINING CONTINUITY OF THE PUBLICLY
AVAILABLE PRODUCTS, BY INTRODUCING THE FOLLOWING CHANGES:
- DOUBLING OF THE MODEL VERTICAL RESOLUTION FROM 64 LAYERS TO
127 LAYERS TO MATCH THE VERTICAL RESOLUTION OF THE GLOBAL
FORECAST SYSTEM (GFS), WHICH PROVIDES MEDIUM-RANGE WEATHER
FORECASTS
- UPDATES TO THE FENGSHA DUST EMISSIONS SCHEME, LARGE SCALE WET
SCAVENGING, AND SETTLING VELOCITY
- UPDATED CHEMICAL MECHANISM TO THE GOCART2G AEROSOL MODEL
- UPGRADES TO THE BIOGENIC AND ANTHROPOGENIC EMISSIONS DATASETS
AND PROCESSING TO THE COMMUNITY EMISSIONS DATA SYSTEM (CEDS)
2022 BASE VERSION
- ASSIMILATION OF VISIBLE INFRARED IMAGING RADIOMETER SUITE
(VIIRS) AEROSOL OPTICAL DEPTH (AOD) RETRIEVALS PROVIDED BY
NOAA’S NATIONAL ENVIRONMENTAL SATELLITE, DATA, AND INFORMATION
SERVICE (NESDIS) IN A 3D-VARIATIONAL ANALYSIS FOUR TIMES PER DAY
USING JEDI
THE PROPOSED GCAFSV1.0 IMPLEMENTATION WILL BE ACCOMPANIED BY THE
RETIREMENT OF THE GEFS V12 AEROSOL PRODUCT AS DESCRIBED IN THE
PUBLIC INFORMATION STATEMENT 25-52
HTTPS://WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF_2025/PNS25-
52_SOLICITING_COMMENTS_GEFS_AEROSOL_TERMINATION.PDF.
MORE INFORMATION ON THE PRODUCTS PROVIDED BY GCAFS V1.0 CAN BE
FOUND AT THE FOLLOWING LINK:
HTTPS://WWW.WEATHER.GOV/MEDIA/NOTIFICATION/REF/GCAFS_V1_PRODUCTS
_SUPPLEMENTAL.PDF
PLEASE SUBMIT COMMENTS, QUESTIONS, OR REQUESTS ON THE PROPOSED
GCAFSV1 IMPLEMENTATION TO:
DR. FANGLIN YANG
CHIEF, PHYSICS AND DYNAMICS DIVISION
NCEP/ENVIRONMENTAL MODELING CENTER
COLLEGE PARK, MD
EMAIL: FANGLIN.YANG@NOAA.GOV
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION
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