SEE PRODUCTS / SEE Related Model & DB -
Thermosphere (Solar and Thermal Environment)
EARTH GLOBAL REFERENCE
ATMOSPHERIC MODEL (Earth-GRAM 2010)
Global model, using empirical database, giving density,
temperature, pressure, winds, and selected atmospheric
constituent concentrations, from the surface of the Earth to
orbital altitudes, as a function of geographic position and
time of year. Local perturbations about mean conditions are
also included. Model is also suitable for use as a subroutine
in a trajectory code or orbit propagator program or other
programs used for simulations of in-flight or on-orbit
atmospheric variability in density, temperature, or winds.
New Features of GRAM 2010 -
1. Updated the
lower atmosphere database Replaced Global Upper Air
Climatic Atlas (GUACA) climatology with monthly global
climatology (means and standard deviations) from
National Centers for Environmental Prediction (NCEP)
Reanalysis Project. This database is now provided with
the GRAM2010 software package. The default NCEP period
of record is 1990-2008 and includes means and standard
deviations for four times of day (00UT, 06UT, 12UT, and
18UT). Thus the user now has the option of selecting
the monthly average at these specific times of day.
boundary layer model Added effects of time-of-day and
atmospheric stability on boundary layer height and
vertical wind standard deviations in the boundary layer.
thermosphere models Replaced JB2006 thermosphere model
with new JB2008. Used global climatology of chemical
release winds to revise wind perturbation standard
deviations in the 90-120 km altitude range.
code to double precision Fortran 90 Also converted all
common blocks to modules, with consistent variable
names. Added interface modules. Changed identifiers
on subroutines, functions, etc. from _E07 to _E10.
Added _E10 suffixes to all subroutine and function names
in the three thermosphere models.
_e10 suffix to header line of namelist input file
5. New scaling
parameter for standard deviations The user now has the
option of independently increasing the standard
deviations of the horizontal wind, the vertical wind,
and the thermodynamic variables (density, temperature,
6. New Range
Reference Atmosphere (RRA) input parameter User has
the option to provide a file name for list of available
sites. Different RRA sites or combinations of sites can
be made available by building various RRA lists, and the
RRA set to use controlled at run time.
7. New option
for auxiliary profiles Added option to input standard
deviations (sigmas) in auxiliary profiles. If zero
values are entered, sigmas are taken from conventional
climatology. An exception to this is for isolated zero
values for sigmas, which are set the same as the
previous (non-zero) sigma.
corrections Revised use of Elliott-Gaffen moisture
corrections, to take advantage of all moisture variables
available in the of NCEP data. Revised calculation of
standard deviation of relative humidity (RH), to account
for correlation between vapor pressure and saturation
vapor pressure (correlation evaluated empirically from
study of NCEP RH data).
output parameters Added mean sound speed and perturbed
sound speed to "print format" and "special format"
output files. Added output of wind speed means and
standard deviations, and cross correlation between
Eastward and Northward wind components (Ruv). Ruv is
used to compute the wave-like large-scale northward wind
perturbation in such a way as to produce the appropriate
degree of cross-correlation.
Language: FORTRAN 90
Operating System: PC/DOS, Unix
Hardware Requirements: Runs on PC (or compatible) and on
most Unix hardware. Need at least 2 GIG of storage space.
Geographic position, time, NCEP data (provided), solar and
geo-magnetic data (for heights above 90 km)
- Maintenance/ Upgrades: On an
as needed basis
- Source Code: Source code is
Program: No cost to qualified, NASA approved users
- Distribution: Available upon request at
- Manuals: Yes
- Training: No
Output Format: Density, temperature, pressure, winds, and
selected atmospheric constituent concentrations, from the
surface of the Earth to orbital altitudes.
Verification/ Validation: Model is
based on empirical data and validated against other empirical
data and previous models.
NASA Marshall Space Flight Center
MSFC, AL 35812
Phone: (256) 544-3694
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