The content of the ARM website is available to any browser, but for the best experience we highly recommend you upgrade to a standards-compliant browser such as Firefox, Opera or Safari.
VIEW CART
primary link menu HOME SITE INDEX PEOPLE
skip to main content ABOUT ARMABOUT ACRFSCIENCESITESINSTRUMENTSMEASUREMENTSDATAPUBLICATIONSEDUCATIONFORMS

Order Data

Or use the datastream interface at the ARM Archive.

Documentation

Questions/Comments?

We would love to hear from you! Call us at 1-888-ARM-DATA.

National Centers for Environment Prediction Global Forecast System (NCEPGFS)

Information updated on July 30, 2009, 2:30 pm GMT


General Data Description

Since 2001, NCEP NWP forecasts (global spectral model) have been processed by Hualu Pan at NCEP/EMC and archived by Stephen Krueger at University of Utah to produce station-like column outputs at locations corresponding to the ARM and other field campaign sites. All data from Jan 2001 up to now have been re-processed by Fanglin Yang for easy access, for comparison with ARM observations, and for driving single column models and cloud resolving models.

The archived forecasts include two runs, initialized at 00Z and 12Z, respectively, and each extends up to 48 hours. Because the vertical layer of the NWP model has been changing, the archived vertical profiles on model sigma layers have been projected on both standard isobaric layers ( 1000-25 hPa, at 25-hPa resolution) and standard heights (0-20 km, 250-m resolution). Outputs on original sigma levels are also provided.

The 48-hour forecasts are saved at a three-hour interval, and saved as past 3-hour means for fluxes (radiation, sensible and latent flux, wind stress), as accumulations for snow and rainfall, and as instantaneous values for state and tendency variables (temp and wind etc).

NCEP NWP Model Configuration

before and on 00Z29oct2002 T170L42 (~75km resolution 2-layer soil model)
12Z29oct2002 to 00Z31may2005 T254L64 (~55km resolution, 2-layer soil model)
since 12Z31may2005 T382L64 (~33km resolution, 4-layer new soil model)

Note the following from Fanglin Yang:

"To simplify the coding, I have set the model forecasts as if missing for the following times: 12Z29oct2002, 00Z30oct2002, 12Z30oct2002, 00Z31oct2002, 12Z31oct2002, and pretended that the T170L42 model was still used, so that the sigma-layer profiles for oct 2002 could all be written as 42 layers. The same trick was applied for output in May 2005 (12Z30may2005 forecast was set as missing)."

Expand All Collapse All

Data Stream Names

Measurement Description

[site]ncepgfs[fac]sfcX1.c1

Surface variables (25 variables, for T170 and T254 with 2-layer soil model, before and on 05-31-2005)

netCDF varname description
pressure model surface pressure for the station ( 0.001*Pa)
pressure_tend surface pressure tendency (Pa/sec)
temp model surface temperature (K)
soil_moist1 first layer soil volumetric water content, liquid+ice
soil_moist2 second layer soil volumetric water content, liquid+ice
snowdepth water equivalent snow depth (cm)
soil_temp1 soil temperature, first layer (K)
soil_temp2 soil temperature, second layer (K)
soil_temp3 soil temperature, deep layer, fixed for time (K)
rough_len model surface roughness length (cm)
conv_a model convective cloud fraction ()
conv_bpres model convective cloud base pressure (1000*Pa)
conv_tpres model convective cloud top pressure (1000*Pa)
albedo1 surface albedo, UV+PAR, direct beam
albedo2 surface albedo, UV+PAR, diffuse beam
albedo3 surface albedo, NIR, direct beam
albedo4 surface albedo, NIR, diffuse beam
sea_land_ice sea(0) land(1) and ice(2) flag
veg_frac model vegetation fraction ()
f10m model 10-meter to sigma level1 similarity profile ratio ()
canopy_water canopy water content (m)
veg_type vegetation type 1-13
soil_type soil type 1-9 ()
veg_frac1 vegetation fraction for surface albedo with strong zenith-angle dependence
veg_frac2 vegetation fraction for surface albedo with weak zenith-angle dependence

Surface variables (46 variables, for T382 with 4-layer soil model, from 06-01-2005 and on)

netCDF varname description
pressure model surface pressure for the station ( 0.001*Pa)
pressure_tend surface pressure tendency (Pa/sec)
temp model surface temperature (K)
soil_moist1 first layer soil volumetric water content, liquid+ice
soil_moist2 second layer soil volumetric water content, liquid+ice
soil_moist3 third layer soil volumetric water content, liquid+ice
soil_moist4 fourth layer soil volumetric water content, liquid+ice
snowdepth water equivalent snow depth (cm)
soil_temp1 soil temperature, first layer (K)
soil_temp2 soil temperature, second layer (K)
soil_temp3 soil temperature, third layer (K)
soil_temp4 soil temperature, fourth layer (K)
soil_temp5 soil temperature, deep layer, fixed for time (K)
rough_len model surface roughness length (cm)
conv_a model convective cloud fraction ()
conv_bpres model convective cloud base pressure (1000*Pa)
conv_tpres model convective cloud top pressure (1000*Pa)
albedo1 surface albedo, UV+PAR, direct beam
albedo2 surface albedo, UV+PAR, diffuse beam
albedo3 surface albedo, NIR, direct beam
albedo4 surface albedo, NIR, diffuse beam
sea_land_ice sea(0) land(1) and ice(2) flag
veg_frac model vegetation fraction ()
f10m model 10-meter to sigma level1 similarity profile ratio ()
canopy_water canopy water content) (m)
veg_type vegetation type 1-13
soil_type soil type 1-9 ()
veg_frac1 vegetation fraction for surface albedo with strong zenith-angle dependence
veg_frac2 vegetation fraction for surface albedo with weak zenith-angle dependence
ustar frictional speed (m/s)
fm Fm for computing surface momentum flux
fh Fh for computing surface momentum flux
ice_thickness sea ice thickness (m)
ice_fraction sea ice fraction
precip_cts precipitation at model current time step (m)
snow_rain snow-rain flag (1=snow, 0=rain)
snowdepth_ol actual snow depth over land (mm)
slc1 first layer soil volumetric water content, liquid
slc2 second layer soil volumetric water content, liquid
slc3 third layer soil volumetric water content, liquid
slc4 fourth layer soil volumetric water content, liquid
shd_min observed minimum vegetation cover fraction
shd_max observed maximum vegetation cover fraction
slope slope type (integer 1-9)
snow_albedo maximum snow albedo
orography orography (m) 
!------------------------------------------------------------------------
! The 9 Soil Types are:
!    1  ... loamy sand (coarse)
!    2  ... silty clay loam (medium)
!    3  ... light clay (fine)
!    4  ... sandy loam (coarse-medium)
!    5  ... sandy clay (coarse-fine)
!    6  ... clay loam  (medium-fine)
!    7  ... sandy clay loam (coarse-med-fine)
!    8  ... loam  (organic)
!    9  ... ice (use loamy sand property)
!------------------------------------------------------------------------
! The 13 vegetation types are:
!    1  ...  broadleave-evergreen trees (tropical forest)
!    2  ...  broadleave-deciduous trees
!    3  ...  broadleave and needle leave trees (mixed forest)
!    4  ...  needleleave-evergreen trees
!    5  ...  needleleave-deciduous trees (larch)
!    6  ...  broadleave trees with groundcover (savanna)
!    7  ...  groundcover only (perenial)
!    8  ...  broadleave shrubs with perenial groundcover
!    9  ...  broadleave shrubs with bare soil
!   10  ...  dwarf trees and shrubs with ground cover (trunda)
!   11  ...  bare soil
!   12  ...  cultivations (use parameters from type 7)
!   13  ...  glacial
!------------------------------------------------------------------------
! The 9 Slope types after Zobler (1986)
! a prescribed coefficient for each slope type ranges between 0.1-1.0. 
! It modifies the drainage out the bottom of the last
! soil layer.  A larger surface slope implies larger drainage.
!SLOPE CLASS      PERCENT SLOPE
!    1                0-8
!    2                8-30
!    3                > 30
!    4                0-30
!    5                0-8 & > 30
!    6                8-30 & > 30
!    7                0-8, 8-30, > 30
!    8                GLACIAL ICE
!    9                OCEAN/SEA
!------------------------------------------------------------------------

[site]ncepgfs[fac]flxX1.c1

Flux type variables (29 variables)

netCDF varname description
land_sea land(0) sea(1) mask, instantaneous
u_stress stress in zonal direction (N/m**2), 3-hr mean
v_stress stress in meridional direction) (N/m**2), 3-hr mean
sens_heat sensible heat flux (W/m**2), 3-hr mean
lat_heat latent heat flux (W/m**2), 3-hr mean
lw_down_surf downward long wave flux at surface (W/M**2), 3-hr mean
lw_up_surf upward long wave flux at surface (W/M**2), 3-hr mean
lw_up_toa upward long wave flux at toa (W/M**2), 3-hr mean
sw_up_toa upward short wave flux at toa (W/M**2), 3-hr mean
sw_up_surf upward short wave flux at surface (W/M**2), 3-hr mean
sw_down_surf downward short wave flux at surface (W/M**2), 3-hr mean
high_a high cloud fraction (), instantaneous
mid_a mid cloud fraction (), instantaneous
low_a low cloud fraction (), instantaneous
precip precipitation accumulated between outputs (kg/m**2), 3-hr accumulation
conv_precip conv precipitation accumulated between outputs (kg/m**2), 3-hr accumulation
ground_hflx ground heat flux (W/m**2)
u10_wind model derived 10-meter zonal wind (m/s), instantaneous
v10_wind model derived 10-meter meridional wind (m/s), instantaneous
temp2 model derived 2-meter temperature (K), instantaneous
spec_h2 model derived 2-meter specific humidity (g/g), instantaneous
pres1 surface pressure again (Pa), instantaneous
temp_max maximum temp between outputs (K), instantaneous
temp_min minimum temp between outputs (K), instantaneous
u_grw zonal stress due to gravity wave drag (W/m**2), 3-hr mean
v_grw meridional stress due to gravity wave drag (W/m**2), 3-hr mean
hpbl model diagnosed planetary boundary layer depth (m), instantaneous
albedo effective model albedo..derived, instantaneous
pbl_a pbl cloud fraction, instantaneous

[site]ncepgfs[fac]sprofX1.c1

Vertical profiles on model sigma layers (12 variables)

netCDF varname description
pressure pressure (0.001*Pa)
u_wind zonal wind velocity (m/s)
v_wind model meridional wind velocity (m/s)
temp temperature (K)
spec_humidity specific humidity (g/g)
rh relative humidity
vert_vel vertical velocity (0.001*Pa/sec)
temp_tend temperature tendency by advection (K/sec)
wv_tend water vapor tendency by advection (g/g/sec)
cloud_water cloud water+ice concentration (g/g)
cloud_water_tend cloud water+ice tendency by advection (g/g/sec)
cloud_fraction cloud fraction

[site]ncepgfs[fac]pprofX1.c1 and [site]ncepgfs[fac]zprofX1.c1

Vertical profiles on standard pressures and heights (11 variables)

netCDF varname NCEP description
u_wind zonal wind velocity (m/s)
v_wind model meridional wind velocity (m/s)
temp temperature (K)
spec_humidity specific humidity (g/g)
rh relative humidity
vert_vel vertical velocity (0.001*Pa/sec)
temp_tend temperature tendency by advection (K/sec)
wv_tend water vapor tendency by advection) (g/g/sec)
cloud_water cloud water+ice concentration (g/g)
cloud_water_tend cloud water+ice tendency by advection (g/g/sec)
cloud_fraction cloud fraction

Temporal Coverage

GEC available since 12/12/2005
GRW available since 04/01/2009
HFE available from 05/01/2008 to 12/31/2008
FKB available from 03/10/2007 to 12/31/2007
NIM available from 04/01/2005 to 12/31/2006
NSA Barrow available since 01/01/2001
NSA Atqasuk available since 12/01/2004
PYE available from 04/01/2005 to 03/31/2006
SGP available since 01/01/2001
TWP Darwin available since 09/01/2002
TWP Manus available since 01/01/2001
TWP Nauru available since 01/01/2001

Area Covered

For NSA Atqasuk, NSA Barrow, SGP, GRW and all the TWP sites, the area covered is a single grid cell of the model. There are two grid points for PYE and nine (from 04/01/2005 to 11/30/2005) or twenty five (since 12/01/2005) grid points for NIM. There are six grid points for FKB and four grid points for China. The latitudes and longitudes are shown below.

GEC Full GFS Domain
GRW (39N, 28E) Graciosa Island, Azores
HFE (31.37N, 120.25E) Taihu
HFE (39.69N, 117E) Xianghe
HFE (32.49N, 116.75E) Shouxian
HFE (39.01N, 100.69E) Zhanghe
FKB (48.55N, 8.41E) Heselbach
FKB (48.64N, 8.07E) Achern
FKB (48.64N, 8.81E) Deckenpfronn
FKB (48.60N, 8.20E) Hornisgrinde
FKB (48.44N, 7.55E) Voges Mountains
FKB (48.74N, 7.61E) Waltenheim
NIM (12.80N, 1.27E) since 04/01/2005
NIM (12.80N, 2.27E) since 04/01/2005
NIM (12.80N, 3.27E) since 04/01/2005
NIM (13.80N, 1.27E) since 04/01/2005
NIM (13.80N, 2.27E) since 04/01/2005
NIM (13.80N, 3.27E) since 04/01/2005
NIM (14.80N, 1.27E) since 04/01/2005
NIM (14.80N, 2.27E) since 04/01/2005
NIM (14.80N, 3.27E) since 04/01/2005
NIM (11.80N, 0.27E) since 12/01/2005
NIM (11.80N, 1.27E) since 12/01/2005
NIM (11.80N, 2.27E) since 12/01/2005
NIM (11.80N, 3.27E) since 12/01/2005
NIM (11.80N, 4.27E) since 12/01/2005
NIM (12.80N, 0.27E) since 12/01/2005
NIM (12.80N, 4.27E) since 12/01/2005
NIM (13.80N, 0.27E) since 12/01/2005
NIM (13.80N, 4.27E) since 12/01/2005
NIM (14.80N, 0.27E) since 12/01/2005
NIM (14.80N, 4.27E) since 12/01/2005
NIM (15.80N, 0.27E) since 12/01/2005
NIM (15.80N, 1.27E) since 12/01/2005
NIM (15.80N, 2.27E) since 12/01/2005
NIM (15.80N, 3.27E) since 12/01/2005
NIM (15.80N, 4.27E) since 12/01/2005
NSA Barrow (71.23S, 156.62W)
NSA Atqasuk (70.47N, 157.41W)
PYE (38.09N, 122.96W)
PYE (38.20N, 123.30W)
SGP CF (36.61N, 97.49W)
TWP Darwin (13.43S, 130.89W)
TWP Manus ( 2.06S, 147.43E)
TWP Nauru ( 0.52S, 166.92E)

Data Stream Inputs

fkbncepgfsX1.00
grwncepgfsX1.00
hfebncepgfsX1.00
nimncepgfsX1.00
nsancepgfsatkX1.00
nsancepgfsbrwX1.00
pyencepgfsX1.00
sgpncepgfsX1.00
twpncepgfsdarX1.00
twpncepgfsmanX1.00
twpncepgfsnauX1.00

Notification Form Link

notification form

Related Links

NCEP notes on model changes
NCEP GFS Documentation

Contacts

Data Source

Data User Notes

The elevation at Xianghe is -24.7 meter. Here is the note from Fanglin Yang. "Xianghe's elevation is indeed -24.7 in the NCEP GFS. It looks strange, but this is the feature of most spectral models. The wave-truncation effect exists near coastal and over oceanic regions."

Acronyms

EMCEnvironmental Modeling Center
FKBBlack Forest, Germany
GECGlobal Earth Coverage
GFSGlobal Forecast System
GRWGraciosa Island, Azores
HFEChina
NCEPNational Centers for Environmental Prediction
NIMNiamey, Niger, Africa
NSANorth Slope of Alaska
NWPNumerical Weather Prediction
PYEPoint Reyes, California
SGPSouthern Great Plains
TWPTropical Western Pacific

Citable References

Fanglin Yang, Hua-Lu Pan, Steve Krueger, Shrinivas Moorthi, Stephen Lord, 2005: Evaluation of the NCEP Global Forecast System at the ARM SGP Site. Manuscript submitted to Mon. Wea. Rew.