A thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (time-GCM): Equinox solar cycle minimum simulations (30–500 km)

A new simulation model of the mesosphere, thermosphere, and ionosphere with coupled electrodynamics has been developed and used to calculate the global circulation, temperature and compositional structure between 30-500 km for equinox, solar cycle minimum, geomagnetic quiet conditions. The model incorporates all of the features of the NCAR thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) but the lower boundary has been extended downward from 97 to 30 km (10 mb) and it includes the physical and chemical processes appropriate for the mesosphere and upper stratosphere. The first simulation used Rayleigh friction to represent gravity wave drag in the middle atmosphere and although it was able to close the mesospheric jets it severely damped the diurnal tide. Reduced Rayleigh friction allowed the tide to penetrate to thermospheric heights but did not close the jets. A gravity wave parameterization developed by Fritts and Lu allows both features to exist simultaneously with the structure of tides and mean flow dependent upon the strength of the gravity wave source. The model calculates a changing dynamic structure with the mean flow and diurnal tide dominant in the mesosphere, the in-situ generated semi-diurnal tide dominating the lower thermosphere and an in-situ generated diurnal tide in the upper thermosphere.more » The results also show considerable interaction between dynamics and composition, especially atomic oxygen between 85 and 120 km. 31 refs., 3 figs.« less

[1]  R. Dickinson,et al.  Global circulation and temperature structure of thermosphere with high‐latitude plasma convection , 1982 .

[2]  R. Dickinson,et al.  Thermospheric general circulation with coupled dynamics and composition , 1984 .

[3]  Raymond G. Roble,et al.  A coupled thermosphere/ionosphere general circulation model , 1988 .

[4]  D. Strobel,et al.  Parameterization of IR cooling in a middle atmosphere dynamics model: 1. Effects on the zonally averaged circulation , 1982 .

[5]  M. Larsen,et al.  Comparisons of spectral thermospheric general circulation model simulations and E and F region chemical release wind observations , 1993 .

[6]  V. Fomichev,et al.  Parameterization of the radiative flux divergence in the 9.6 μm O3 band , 1985 .

[7]  Byron A. Boville,et al.  Upper Boundary Effects in a General Circulation Model , 1988 .

[8]  R. Dickinson,et al.  Simulation of the thermospheric tides at equinox with the National Center for Atmospheric Research Thermospheric General Circulation Model , 1986 .

[9]  D. Fritts,et al.  Spectral Estimates of Gravity Wave Energy and Momentum Fluxes. Part II: Parameterization of Wave Forcing and Variability , 1993 .

[10]  T. Fuller‐Rowell,et al.  A Three-Dimensional Time-Dependent Global Model of the Thermosphere , 1980 .

[11]  W. Ward,et al.  On the role of atomic oxygen in the dynamics and energy budget of the mesosphere and lower thermosphere , 1993 .

[12]  J. Forbes,et al.  Acceleration, heating, and compositional mixing of the thermosphere due to upward propagating tides , 1993 .

[13]  Raymond G. Roble,et al.  A three‐dimensional general circulation model of the thermosphere , 1981 .

[14]  J. Mahlman,et al.  Interactions between Gravity Waves and Planetary-Scale Flow Simulated by the GFDL “SKYHI” General Circulation Model , 1986 .

[15]  M. Mlynczak,et al.  A detailed evaluation of the heating efficiency in the middle atmosphere , 1993 .

[16]  G. Brasseur,et al.  An interactive chemical dynamical radiative two-dimensional model of the middle atmosphere , 1990 .

[17]  A. Mitra,et al.  Ionospheric effects of solar flares—VI. Changes in D-region ion chemistry during solar flares☆ , 1972 .

[18]  B. Hunt A simulation of the gravity wave characteristics and interactions in a diurnally varying model atmosphere , 1990 .

[19]  R. P. Lowe,et al.  Longitudinal structure in atomic oxygen concentrations observed with WINDII on UARS , 1993 .

[20]  Raymond G. Roble,et al.  On the global mean structure of the thermosphere , 1987 .

[21]  M. Molina,et al.  Chemical kinetics and photochemical data for use in stratospheric modeling , 1985 .

[22]  S. Liu,et al.  Mesospheric Hydrogen Related to Exospheric Escape Mechanisms , 1974 .

[23]  Yuk L. Yung,et al.  The Vertical Distribution of Ozone in the Mesosphere and Lower Thermosphere , 1984 .

[24]  V. Fomichev,et al.  Parameterization of the 15 μm CO2 band cooling in the middle atmosphere (15–115 km) , 1993 .

[25]  Paul G. Richards,et al.  Mid‐ and low‐latitude model of thermospheric emissions: 1. O+ (²P) 7320 Å and N2 (2P) 3371 Å , 1990 .

[26]  Jeffrey M. Forbes,et al.  Atmospheric tides: 1. Model description and results for the solar diurnal component , 1982 .

[27]  Raymond G. Roble,et al.  A thermosphere/ionosphere general circulation model with coupled electrodynamics , 1992 .