UKSSDC archive of WACCM-X model data
1950–2024

Data Download

Date selection

As these daily files are quite large, ≈3GB, there is currently a limit of 7 files per request. If you need more you should contact the UKSSDC staff and alternative access methods such as rsync can be arranged.

Dataset

Files are in netcdf (HDF5) format. They are split into daily output, named WACCMXhistory.cam.h1.YYYY-MM-DD-00000.nc, where YYYY-MM-DD is replaced with the date the file corresponds to.

Latitude span:
-90 to 90 degrees at 1.9 degree resolution (96 steps)
Longitude span:
0 to 357.5 degrees at 2.5 degree resolution (144 steps)
Levels:
126 levels at quarter scale height resolution from ground-level to ~400–700 km (upper boundary varies in altitude as the atmosphere expands)
Time:
01-01-1950T00:00:00 to 31-12-2024T23:00:00 at hourly resolution
Time format used:
days (as a float) since the date stored in the time metadata (since the model start, noting the model run was split into 3 so not all start from 1950-01-01).

Data Description

Short name Long name Coordinates Units
gw Latitude weights 1D: lat
hyam hybrid A coefficient at layer midpoints 1D: lev
hybm hybrid B coefficient at layer midpoints 1D: lev
P0 reference pressure None Pa
hyai hybrid A coefficient at layer interfaces 1D: ilev
hybi hybrid B coefficient at layer interfaces 1D: ilev
date current date (YYYYMMDD) 1D: time
datesec current seconds of current date 1D: time
time_bnds time interval endpoints 1D: time
date_written Date model ran 1D: time
time_written Time model ran 1D: time
ndbase base day None
nsbase seconds of base day None
nbdate base date (YYYYMMDD) None
nbsec seconds of base date None
mdt timestep None s
ndcur current day (from base day) 1D: time
nscur current seconds of current day 1D: time
co2vmr co2 volume mixing ratio 1D: time ppm
ch4vmr ch4 volume mixing ratio 1D: time ppm
n2ovmr n2o volume mixing ratio 1D: time ppm
f11vmr f11 volume mixing ratio 1D: time ppm
f12vmr f12 volume mixing ratio 1D: time ppm
sol_tsi total solar irradiance 1D: time Wm-2
f107 10.7 cm solar radio flux (F10.7) 1D: time sfu
f107a 81-day centered mean of 10.7 cm solar radio flux (F10.7) 1D: time sfu
f107p Previous day 10.7 cm solar radio flux (F10.7) 1D: time sfu
kp Daily planetary K geomagnetic index 1D: time
ap Daily planetary A geomagnetic index 1D: time
colat_crit1 First co-latitude of electro-potential critical angle 1D: time degrees
colat_crit2 Second co-latitude of electro-potential critical angle 1D: time degrees
nsteph current timestep 1D: time
CO2 CO2 concentration 4D (lev) mol/mol
EDens e Number Density (sum of O2+,NO+,N2+,O+) 4D (lev) cm3
H H concentration 4D (lev) mol/mol
N N concentration 4D (lev) mol/mol
N2_vmr invariant density 4D (lev) mol/mol
NO NO concentration 4D (lev) mol/mol
O O concentration 4D (lev) mol/mol
O2 O2 concentration 4D (lev) mol/mol
Op Op concentration 4D (lev) mol/mol
PS Surface pressure Surface (lat, lon, time) Pa
QJOULE Joule Heat 4D (lev) Ks-1
T Temperature 4D (lev) K
TElec Electron Temperature 4D (lev) K
TIon Ion Temperature 4D (lev) K
U Zonal wind 4D (lev) ms-1
V Meridional wind 4D (lev) ms-1
Z3 Geopotential Height (above sea level) 4D (lev) m
He He concentration (scaled from MSIS) 4D (lev) mol/mol
DEN Neutral density from ideal gas law 4D (lev) kgm-3
Notes

  1. 4D is lat, lon, time, and either lev or ilev
  2. 1 sfu is 10-22 W m-2 Hz-1
  3. mol/mol are volume mixing ratios

  1. To convert the volume mixing ratios to mass densities, first calculate the total number density, n tot , by n tot = 100 · lev / k B / T where k B is the Boltzmann constant, and T (temperature) and lev (level) are available in the files.
    Then calculate the total mass density of a constituent, rho n , by rho n = n tot · vmr n · M n · L where L is the Avogadro constant, M n is the molar mass of the constituent, and vmr n is the volume mixing ratio of the constituent from the file (i.e. O for atomic oxygen).
  2. Helium (He) and neutral density (DEN) were added post-run. This has been done by scaling the helium number density from the empirical, Naval Research Lab Mass Spectrometer and Incoherent Scatter radar (NRLMSISE-00) mode, by the ratio of the sums of O, O2, N2 number densities in WACCM-X to the similar sum in NRLMSISE-00. Neutral mass densities for each constituent were then calculated and summed for DEN.