EMC Operational Models
Global Forecast System
Mark Iredell
Acting GCWMB chief,
Environmental Modeling Center
NOAA / NWS / NCEP
Mark.Iredell@NOAA.gov
UMAC data call
Global Forecast System (GFS)
page 1 of 16
Unified Coupled Global Model
Whole
Atmosphere
Model
NGGPS
Unified Global Coupled Model
Application
=
Ensemble
+
Reanalysis
+
Reforecast
“GFS”
“GEFS”
“CFS”
Actionable
weather
Week 1
through 4-6
Seasonal &
annual
1y
2y
4y
Update cycle
3y
20-25 y
1979 - present
Reanalysis
6h
6-24h
???
cycling
WCOSS
WCOSS
WCOSS ?
where
UMAC data call
Global Forecast System (GFS)
page 2 of 16
Description of the operational GFS:
Dynamics
Global Spectral Model (dynamics)
• T1534 horizontal resolution and 64 hybrid sigma-pressure
vertical grid.
• Two time level semi-Lagrangian semi-implicit dynamics with
SETTLS approximation on a linear grid of 3072x1536 with a
resolution of 13km at the equator.
• 450s dynamics time step and 225s physics time step
• Hermite interpolation in SL dynamics
• 8th order horizontal diffusion (gridded-tracer option)
• Divergence damping in the stratosphere
• 3 tracers: specific humidity, ozone, and cloud condensate
UMAC data call
Global Forecast System (GFS)
page 3 of 16
Description of the operational GFS:
Physics
Physics
Description
Convection
Simplified Arakawa-Schubert (SAS) and mass flux based SAS
shallow convection scheme
Optional: Relaxed Arakawa-Schubert (RAS)
Microphysics
Zhao-Carr-Sundqvist based microphysics formulation for grid-scale
condensation and precipitation
Optional: Ferrier Microphysics
Gravity Wave Drag
Orographic gravity wave drag, mountain-drag and stationary
convective gravity wave drag
PBL
Hybrid Eddy Diffusion Mass flux turbulence/vertical diffusion
scheme
Radiation
Solar radiation and IR based on RRTM (originally from AER,
modified at EMC) with Monte Carlo Independent Column
Approximation (McICA). Cloud fraction for radiation computed
diagnostically from prognostic cloud condensate
UMAC data call
Global Forecast System (GFS)
page 4 of 16
Description of the operational GFS:
Physics
Physics
Description
Ozone/aerosols
Prognostic ozone with parameterized production and destruction
from NRL and Climatological aerosols; Global mean ozone fixer for
correcting non conservative tracer advection
Damping
Rayleigh damping in the stratosphere
Dissipative Heating
Heating associated with Kinetic energy dissipation
SST
Analyzed Sea surface temperature that e-folds to climatology with
a time scale of 90 days
Ice
3 layer ice model
Physics
perturbations for DA
Stochastic physics for the ensembles used in hybrid-ENKF
Ocean Coupling
None - Coupling to MOM4 ocean model is an option
Land Surface
Noah 4 level land model
UMAC data call
Global Forecast System (GFS)
page 5 of 16
Description of the operational GFS:
Unified Post-Processing System (UPP)
Post Processing
•
•
•
•
•
Unified Post Processor (UPP) shared across EMC
General sea level pressure and isobaric fields
Selectable diagnostic products
World Area Forecast System (WAFS)
GRIB2 encoding
UMAC data call
Global Forecast System (GFS)
page 6 of 16
Improvement GFS2015 made
over 3 years of parallel forecasts
see http://www.emc.ncep.noaa.gov/gmb/wx24fy/vsdb/gfs2015/
NH 500-hPa HGT AC
SH 500-hPa HGT AC
significant to 8 days lead time
significant to 10 days lead time
UMAC data call
Global Forecast System (GFS)
page 7 of 16
Forecast Days at Which Height
ACs Exceed Given Critical Values
see http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/longterm/
UMAC data call
Global Forecast System (GFS)
page 8 of 16
Description of the operational GFS:
Global Data Assimilation System
Global Data Assimilation System (GDAS)
•
•
•
•
•
Hybrid 3D EnVar
80 member ensemble 30 km resolution
Ensemble Kalman filter approach
15% static variational background error (NMC method)
Community Radiative Transfer Model (CRTM) shared
across EMC
• Gridded Statistical Interpolation (GSI) application shared
across EMC
• Tropical storm relocation
UMAC data call
Global Forecast System (GFS)
page 9 of 16
FY2015 Global Data Assimilation System: DualResolution Coupled Hybrid Var/EnKF Cycling
(3D-EnVAR)
UMAC data call
Global Forecast System (GFS)
page 10 of 16
Proposed FY2016 Global Data Assimilation
System: Dual-Resolution Coupled Hybrid
Var/EnKF Cycling: (4D-EnVAR)
UMAC data
call
Previous
Cycle
Global
Forecast
System (GFS)
Current
Update
Cycle
11
page 11 of 16
FY2016 Planned GFS Upgrades
2014
2015/2016
Resolution 0-240 h
T574 (23km)
TL1534 (13km) (FY2015)
(out to 192 hours only)
Resolution 240-384 h
T254 (46km)
TL574 (34km) (FY2015)
Global Spectral Model Eulerian transport
Semi-Lagrangian transport
Improved Physics (FY2015)
Data assimilation
Improved satellite assimilation
Stochastic physics (FY2015)
4D Hybrid Envar (FY2016)
All-sky AMSU-A Radiances
(FY2016)
UMAC data call
3D Hybrid Envar
Global Forecast System (GFS)
page 12 of 16
GFS: Future plans for the next 5
years
• Unified coupled global forecast system
–
–
–
–
Earth-Next unifies the weekly, monthly, and seasonal forecasts of the NCEP global forecast
GFS will evolve into the Earth-Next week application.
Separate atmosphere, land, ocean, ice, wave, aerosol, chemistry, ionosphere components
NOAA Environmental Modeling System (NEMS) infrastructure
• Future resolution
–
–
10 km to 10 days; 17 km days 10 to 16
128 levels including 10 meters above the ground and full mesosphere or whole atmosphere
• Future ensembles at highest resolution
–
Considering small ensemble members at highest resolution
• Model dynamics
–
–
–
Non-hydrostatic using GSM or NGGPS candidate
Possible varying horizontal resolution with height
More tracers, aerosols, TKE, O and O2
• Model physics
–
Many efforts to improve parameterizations, particularly cloud processes and boundary layer processes
• Data assimilation
–
More observations and improved algorithms
UMAC data call
Global Forecast System (GFS)
page 13 of 16
GFS Model Verification and
Statistics
Main Verification Web Page: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/
• verification statistics of AC, RMSE, Bias etc for major international NWP models
and GFS implementation parallels in the past 31 days
• real-time weather forecast maps of GFS, ECMWF and GFS implementation
parallels
Grid-to-Obs: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/g2o/ and
http://www.emc.ncep.noaa.gov/gmb/ssaha/
• verifications of surface 2-m T, RH, Td, 10-m winds, SLP and total clouds against
ground observations over the CONUS and its sub-regions
• verifications of atmospheric T, Q, RH and Winds against rawinsonde and aircraft
observations over the globe and its sub-regions.
Precipitation: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/www/rain2/rain.html
• precipitation forecast maps verified against CCPA over the CONUS and CPC
gauge observations over the globe, and precipitation Equitable Threat Scores
for major international models
UMAC data call
Global Forecast System (GFS)
page 14 of 16
GFS Model Verification and
Statistics
Objected-Oriented (MODE) Verification:
http://www.emc.ncep.noaa.gov/gc_wmb/tdorian/
• MODE verifications of precipitation over CONUS and jet streams over the globe.
Historical Performance: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/longterm/
• annual review of GFS forecast skills and historical performances of major
international NWP models.
Data Assimilation Monitoring: http://www.emc.ncep.noaa.gov/gmb/gdas/
GFS Experimental Parallels Verification:
• http://www.emc.ncep.noaa.gov/gmb/wd20rt/vsdb/
• http://www.emc.ncep.noaa.gov/gmb/wx24fy/vsdb/
Others : http://www.emc.ncep.noaa.gov/GFS/perf.php
• contains a list of all verifications related to GFS and GEFS.
• http://www.emc.ncep.noaa.gov/gmb/STATS/MAPS.html presents daily weather
forecast maps.
UMAC data call
Global Forecast System (GFS)
page 15 of 16
GFS Model Documentation
and Products
Main GFS Web Page: http://www.emc.ncep.noaa.gov/index.php?branch=GFS
GFS Model Documentation: http://www.emc.ncep.noaa.gov/GFS/doc.php
Real-time GFS Data Products: http://www.nco.ncep.noaa.gov/pmb/products/gfs/
Real-time GFS Graphical Display: http://mag.ncep.noaa.gov/model-guidancemodel-area.php#
UMAC data call
Global Forecast System (GFS)
page 16 of 16
Sources and selection of requirements
and development path.
Development path
• Developments come via internal employees or external collaborators.
• Developments must be tested against the ‘trunk’ version of the component
(O2R).
• Developments must use the standards and infrastructure set up at EMC for the
component.
• Developments must be delivered via the EMC code repository.
Implementation testing
• EMC will select and combine and validate developments for the next
implementation.
• Full parallel system must be run in real-time and retrospective for 3 warm
seasons and 2 cool seasons.
• Both subjective evaluation by forecasters and objective evaluation by modelers.
• NCO validates the IT specifications before implementation.
UMAC data call
Global Forecast System (GFS)
page 17 of 16
Sources and selection of requirements
and development path.
Model Evaluation Group (MEG)
•
•
•
•
•
Many user requests for improving specific model features come through the
Model Evaluation Group (MEG).
Weekly discussions of recent model performance, generally synoptic.
Presentations and recordings of the meetings are available on line for an
extended period for NOAA personnel only
MEG presentations & recording are posted on a google drive
https://drive.google.com/a/noaa.gov/?tab=wo#folders/0BySqFAN_J6G4cWdpNz
BRMkM4ZVE
Presentations are also posted on the EMC MEG page:
http://www2.emc.ncep.noaa.gov/MEG/MEG-info.html
UMAC data call
Global Forecast System (GFS)
page 18 of 16
Next Generation Global Prediction
System (NGGPS)
Next Generation Global Prediction System (NGGPS)
• The Next Generation Global Prediction System (NGGPS) is a NOAAwide effort to improve global NWP in the NWS.
• Selection of a new global non-hydrostatic dynamical core that is scalable
to 3 km resolution
• Expanded efforts to deliver scale-aware physics parameterizations
• Support for common infrastructure in the NOAA Environmental Modeling
System (NEMS)
• Development of full Earth coupling using NUOPC layer within NEMS
infrastructure
UMAC data call
Global Forecast System (GFS)
page 19 of 16