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Atmospheric models#

MSIS86#

The Mass-Spectrometer-Incoherent-Scatter-1986 (MSIS-86) neutral atmosphere model describes the neutral temperature and the densities of He, O, N2, O2, Ar, H, and N. The MSIS model is based on the extensive data compilation and analysis work of A. E. Hedin and his collaborators [A. E. Hedin et al., J. Geophys. Res. 82, 2139-2156, 1977; A. E. Hedin, J. Geophys. Res. 88, 10170- 10188, 1983; A. E. Hedin, J. Geophys. Res. 92, 4649, 1987]. MSIS-86 constitutes the upper part of the COSPAR International Reference Atmosphere (CIRA-86).

Data sources for the present model include temperature and density measurements from several rockets, satellites (OGO-6, San Marco 3, Aeros-A, AE-C, AE-D, AE-E, ESRO 4 and DE-2) and incoherent scatter radars (Millstone Hill, St. Santin, Arecibo, Jicamarca, and Malvern). Since the MSIS-83 model, terms were added or changed to better represent seasonal variations in the polar regions under both quiet and magnetically disturbed conditions and local time variations in the magnetic activity effect. In addition a new species, atomic nitrogen, was added to the list of species covered by the model.

Inputs:

  • ntime (integer) – number of time points

  • whichAp (integer) –

    key for the kind of Ap input:

    • 1 - only daily Ap magnetic index is provided in the Ap parameter

    • 2 - all fields are provided in the Ap parameter

  • idoy (array of ntime integer) – the day of year (January 1st is idoy=1)

  • UT (array of ntime double) – the time in seconds

  • alt (array of ntime double) – altitude (km, greater than 85km)

  • lat (array of ntime double) – geodetic latitude (deg)

  • long (array of ntime double) – geodetic longitude (deg)

  • F107A (array of ntime double) – 3 month average of F10.7 flux

  • F107 (array of ntime double) – daily F10.7 flux for previous day

  • Ap (array of [7, ntime] double) –

    averaged Ap index

    • 1 - Daily Ap

    • 2 - 3 hours Ap index for current time

    • 3 - 3 hours Ap index for 3 hours before current time

    • 4 - 3 hours Ap index for 6 hours before current time

    • 5 - 3 hours Ap index for 9 hours before current time

    • 6 - Average of eight 3 hours Ap indices from 12 to 33 hours before current time

    • 7 - Average of eight 3 hours Ap indices from 36 to 59 hours before current time

Outputs:

  • dens (array of [8, ntime] double) –

    density:

    • 1 - He number density (cm-3)

    • 2 - O number density (cm-3)

    • 3 - N2 number density (cm-3)

    • 4 - O2 number density (cm-3)

    • 5 - Ar number density (cm-3)

    • 6 - Total mass density (g.cm-3)

    • 7 - H number density (cm-3)

    • 8 - N number density (cm-3)

  • temp (array of [2, ntime] double) –

    temperature:

    • 1 - Exospheric temperature (K)

    • 2 - Temperature at altitude (K)

Calling sequence:
From MATLAB#
out = onera_desp_lib_msis('msis86',date,X,sysaxes,F107A,F107,Ap)
From IDL#
result = call_external(lib_name, 'msis86_idl', ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp, /f_value)
From FORTRAN#
CALL msis86(ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp)
MSISE90#

The MSISE model describes the neutral temperature and densities in Earth’s atmosphere from ground to thermospheric heights. Below 72.5 km the model is primarily based on the MAP Handbook (Labitzke et al., 1985) tabulation of zonal average temperature and pressure by Barnett and Corney, which was also used for the CIRA-86. Below 20 km these data were supplemented with averages from the National Meteorological Center (NMC). In addition, pitot tube, falling sphere, and grenade sounder rocket measurements from 1947 to 1972 were taken into consideration. Above 72.5 km MSISE-90 is essentially a revised MSIS-86 model taking into account data derived from space shuttle flights and newer incoherent scatter results. For someone interested only in the thermosphere (above 120 km), the author recommends the MSIS-86 model. MSISE is also not the model of preference for specialized tropospheric work. It is rather for studies that reach across several atmospheric boundaries.

Inputs:

  • ntime (integer) – number of time points

  • whichAp (integer) –

    key for the kind of Ap input:

    • 1 - only daily Ap magnetic index is provided in the Ap parameter

    • 2 - all fields are provided in the Ap parameter

  • idoy (array of ntime integer) – the day of year (January 1st is idoy=1)

  • UT (array of ntime double) – the time in seconds

  • alt (array of ntime double) – altitude (km, greater than 85km)

  • lat (array of ntime double) – geodetic latitude (deg)

  • long (array of ntime double) – geodetic longitude (deg)

  • F107A (array of ntime double) – 3 month average of F10.7 flux

  • F107 (array of ntime double) – daily F10.7 flux for previous day

  • Ap (array of [7, ntime] double) –

    averaged Ap index

    • 1 - Daily Ap

    • 2 - 3 hours Ap index for current time

    • 3 - 3 hours Ap index for 3 hours before current time

    • 4 - 3 hours Ap index for 6 hours before current time

    • 5 - 3 hours Ap index for 9 hours before current time

    • 6 - Average of eight 3 hours Ap indices from 12 to 33 hours before current time

    • 7 - Average of eight 3 hours Ap indices from 36 to 59 hours before current time

Outputs:

  • dens (array of [8, ntime] double) –

    density:

    • 1 - He number density (cm-3)

    • 2 - O number density (cm-3)

    • 3 - N2 number density (cm-3)

    • 4 - O2 number density (cm-3)

    • 5 - Ar number density (cm-3)

    • 6 - Total mass density (g.cm-3)

    • 7 - H number density (cm-3)

    • 8 - N number density (cm-3)

  • temp (array of [2, ntime] double) –

    temperature:

    • 1 - Exospheric temperature (K)

    • 2 - Temperature at altitude (K)

Calling sequence:
From MATLAB#
out = onera_desp_lib_msis('msise90',date,X,sysaxes,F107A,F107,Ap)
From IDL#
result = call_external(lib_name, 'msise90_idl', ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp, /f_value)
From FORTRAN#
CALL msise90(ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp)
NRLMSISE00#

The NRLMSIS-00 empirical atmosphere model was developed by Mike Picone, Alan Hedin, and Doug Drob based on the MSISE90 model. The main differences to MSISE90 are noted in the comments at the top of the computer code. They involve:

  1. the extensive use of drag and accelerometer data on total mass density,

  2. the addition of a component to the total mass density that accounts for possibly significant contributions of O+ and hot oxygen at altitudes above 500 km, and

  3. the inclusion of the SMM UV occultation data on [O2].

The MSISE90 model describes the neutral temperature and densities in Earth’s atmosphere from ground to thermospheric heights. Below 72.5 km the model is primarily based on the MAP Handbook (Labitzke et al., 1985) tabulation of zonal average temperature and pressure by Barnett and Corney, which was also used for the CIRA-86. Below 20 km these data were supplemented with averages from the National Meteorological Center (NMC). In addition, pitot tube, falling sphere, and grenade sounder rocket measurements from 1947 to 1972 were taken into consideration. Above 72.5 km MSISE-90 is essentially a revised MSIS-86 model taking into account data derived from space shuttle flights and newer incoherent scatter results. For someone interested only in the thermosphere (above 120 km), the author recommends the MSIS-86 model. MSISE is also not the model of preference for specialized tropospheric work. It is rather for studies that reach across several atmospheric boundaries.

Inputs:

  • ntime (integer) – number of time points

  • whichAp (integer) –

    key for the kind of Ap input:

    • 1 - only daily Ap magnetic index is provided in the Ap parameter

    • 2 - all fields are provided in the Ap parameter

  • idoy (array of ntime integer) – the day of year (January 1st is idoy=1)

  • UT (array of ntime double) – the time in seconds

  • alt (array of ntime double) – altitude (km, greater than 85km)

  • lat (array of ntime double) – geodetic latitude (deg)

  • long (array of ntime double) – geodetic longitude (deg)

  • F107A (array of ntime double) – 3 month average of F10.7 flux

  • F107 (array of ntime double) – daily F10.7 flux for previous day

  • Ap (array of [7, ntime] double) –

    averaged Ap index

    • 1 - Daily Ap

    • 2 - 3 hours Ap index for current time

    • 3 - 3 hours Ap index for 3 hours before current time

    • 4 - 3 hours Ap index for 6 hours before current time

    • 5 - 3 hours Ap index for 9 hours before current time

    • 6 - Average of eight 3 hours Ap indices from 12 to 33 hours before current time

    • 7 - Average of eight 3 hours Ap indices from 36 to 59 hours before current time

Outputs:

  • dens (array of [9, ntime] double) –

    density:

    • 1 - He number density (cm-3)

    • 2 - O number density (cm-3)

    • 3 - N2 number density (cm-3)

    • 4 - O2 number density (cm-3)

    • 5 - Ar number density (cm-3)

    • 6 - Total mass density (g.cm-3)

    • 7 - H number density (cm-3)

    • 8 - N number density (cm-3)

    • 9 - Anomalous oxygen number density (cm-3)

  • temp (array of [2, ntime] double) –

    temperature:

    • 1 - Exospheric temperature (K)

    • 2 - Temperature at altitude (K)

Calling sequence:
From MATLAB#
out = onera_desp_lib_msis('nrlmsise00',date,X,sysaxes,F107A,F107,Ap)
From IDL#
result = call_external(lib_name, 'nrlmsise00_idl', ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp, /f_value)
From FORTRAN#
CALL nrlmsise00(ntime,whichAp,DOY,UT,Alt,Lat,Lon,F107A,F107,Ap,Dens,Temp)
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