Some aspects of the circulation of Mars

Estimates of vertical temperature structure, heat balance, solstice circulation, and thermally driven tides on Mars in comparison with like conditions on Eart

Eddy processes in the general circulation of the Jovian atmospheres

Two fundamentally different views of the general circulation of Jovian atmospheres have emerged. According to one view, the observed jet streams at the cloud tops are controlled by the vorticity transfers of small scale eddies generated by planetary wave instabilities within a shallow atmospheric layer. According to the alternate point of view, the zonal jets are surface manifestations of deep interior convection organized into cylindrical motion with axes parallel to the planetary rotation axis. Both approaches may be considered in the context of the very different roles assumed by the potential vorticity. A possible reconciliation of the two kinds of dynamical systems is considered in which the interior motion is overlaid with a statically stable cappling layer driven by turbulent energy injection from below. A simple model for the eddy driving of quasi-geostrophic dynamics in the capping layer is presented which is consistent with the tentative evidence for up-gradient momentum flux on Jupiter and IRIS observations of thermal contrast correlations with cyclonic and anticyclonic shear zones. Certain synoptic-scale cloud features in Jupiter's atmosphere are interpreted as breaking waves, which may also influence the lateral mixing of tracers such as the ortho-para hydrogen ratio

A Numerical General Circulation Experiment for the Atmosphere of Mars

Numerical model for simulating general circulation of atmosphere of Mar

Dynamics of earth and planetary atmospheres: A brief assessment of our present understanding

The present understanding of planetary atmospheres, the application of this knowledge to terrestrial problems, and the research needs in these overlapping areas are assessed

Optical properties of CO2 ice and CO2 snow from ultraviolet to infrared: Application to frost deposits and clouds on Mars

Researchers found that it is possible to grow large clear samples of CO2 ice at Mars-like temperatures of 150-170K if a temperature controlled refrigerator is connected to an isolated two-phase pure CO2 system. They designed a chamber for transmission measurements whose optical path between the 13mm diameter window is adjustable from 1.6mm to 107mm. This will allow measurements of linear absorption down to less than 0.01 cm (exp -1). A preliminary transmission spectrum of a thick sample of CO2 ice in the near infrared was obtained. Once revised optical constants have been determined as a function of wavelength and temperature, they can be applied to spectral reflectance/emissivity models for CO2 snow surfaces, both pure and contaminated with dust and water ice, using previously established approaches. It will be useful, also, to develop an infrared scattering-emission cloud radiance model (especially as viewed from near the limb) in order to develop a strategy for the identification of CO2 cloud layers by the atmospheric infrared radiometer instrument on the Mars Observer

Seasonal wind variations in the Martian subtropics

A possible initiation mechanism for global dust storms was raised by describing a new analysis of winds at Viking Lander I, the Mutch Memorial Station, at 28 deg N latitude. It was shown that strong winds associated with an eastward propagation planetary wave coincided with the onset of a major dust storm at that site, and it was speculated that these high latitude winter systems may sometimes contribute to the initiation of Martian global dust storms

Middle atmosphere project: A radiative heating and cooling algorithm for a numerical model of the large scale stratospheric circulation

A Curtis matrix is used to compute cooling by the 15 micron and 10 micron bands of carbon dioxide. Escape of radiation to space and exchange the lower boundary are used for the 9.6 micron band of ozone. Voigt line shape, vibrational relaxation, line overlap, and the temperature dependence of line strength distributions and transmission functions are incorporated into the Curtis matrices. The distributions of the atmospheric constituents included in the algorithm, and the method used to compute the Curtis matrices are discussed as well as cooling or heating by the 9.6 micron band of ozone. The FORTRAN programs and subroutines that were developed are described and listed

Flux of water vapor in the terrestrial stratosphere and in the Martian atmosphere

A summary of the terrestrial satellite data is presented. The observations indicate that at equatorial latitudes, relatively dry air is introduced at the tropopause and carried to the upper stratosphere. At that altitude, any methane present in the ascending air mass is oxidized photochemically into water vapor. This vapor is eventually transported to high latitudes, where it is carried to the lower stratosphere by the descending leg of the diabatic circulation. The Pressure Modulator Infrared Radiometer instrument aboard the Mars Observer should provide a comparable picture of vapor transport in the martian atmosphere

MECA Symposium on Mars: Evolution of its Climate and Atmosphere

The geological, atmospheric, and climatic history of Mars is explored in reviews and reports of recent observational and interpretive investigations. Topics addressed include evidence for a warm wet climate on early Mars, volatiles on Earth and on Mars, CO2 adsorption on palagonite and its implications for Martian regolith partitioning, and the effect of spatial resolution on interpretations of Martian subsurface volatiles. Consideration is given to high resolution observations of rampart craters, ring furrows in highland terrains, the interannual variability of the south polar cap, telescopic observations of the north polar cap and circumpolar clouds, and dynamical modeling of a planetary wave polar warming mechanism

Thermal tides in the Martian middle atmosphere as seen by the Mars Climate Sounder

The first systematic observations of the middle atmosphere of Mars (35–80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the data set of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian general circulation model to extend our analysis, we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons