Updated Global Atmospheric Reference Model Computer Programs

The 1999 version of the NASA/Marshall Space Flight Center Global Reference Atmospheric Model (GRAM-99) and version 3.8 of the Mars Global Reference Atmospheric Model (Mars- GRAM) are the latest in two series of computer programs for calculating selected physical properties of the atmospheres of Earth and Mars, respectively. GRAM-99, like prior versions of GRAM, implements an amalgamation of empirical models that represent geographical, seasonal, and monthly variations of the state of the terrestrial atmosphere (thermodynamic variables and horizontal and vertical wind components) at all altitudes from the ground up to those of spacecraft orbits. Mars-GRAM provides engineering estimates of density, temperature, pressure, and wind components in the Martian atmosphere as functions of latitude, longitude, altitude, and time.