The GRAM model: Status of development and future aspects

Abstract

The NASA Marshall Space Flight Center's Global Reference Atmospheric Model has been updated to a 1995 version (GRAM-95). GRAM-95 has a middle atmosphere (20 to 120 km) climatology based on extensive summaries from Middle Atmosphere Program (MAP) data. GRAM-95 also updates the lower altitude (0 – 27 km) region with Global Upper Air Climatic Atlas (GUACA) data (based on a climatology of European Center for Medium-Range Weather Forecasting (ECMWF) data). Like earlier versions, GRAM-95 includes global-scale, monthly-mean values for temperature, density, pressure, and wind components at all altitudes. Based primarily on MAP species concentration climatologies, GRAM-95 now includes estimates for water vapor and other species (including O 3, N 2O, CO, CH 4, CO 2, N 2, O 2, O, A, He, and H). A revised perturbation model in GRAM-95 simulates the statistical characteristics of both small-scale and large-scale processes, including variations of thermodynamic properties and wind components. Example outputs are presented and possible future developments are summarized.