Remote sounding of the Martian atmosphere in the context of the InterMarsNet mission: General circulation and meteorology

A concept has been developed for a remote sensing experiment to investigate the physics of the Martian atmosphere from a spin-stabilized orbiter, like that planned for the InterMarsNet mission. Using coincident infrared and microwave channels and limb-to-limb scanning, it can map the planet much more extensively than previously in temperature, atmospheric dust loading, and humidity. When combined with one or more surface stations measuring the same variables, the sounder experiment can contribute to major progress in understanding the general circulation and dust and water cycles of the atmosphere of Mars, and the characterization of medium-scale meteorological systems. Copyright © 1996 Elsevier Science Ltd

Western boundary currents in the atmosphere of Mars

Western boundary currents (WBCs) are an intensification of north-south flow adjacent to an eastward-facing meridional boundary. Although most familiar in the oceans (where the Gulf Stream is the best known example), WBCs also occur in the Earth's troposphere. The main example being the East African Jet, which is thought to play an important role in the Asiatic monsoon. Here we identify boundary currents in a different geophysical context: a numerical simulation of the atmosphere of Mars. In our simulation. WBCs exist in association with significant cross-equatorial flow and the presence of equatorial martian topography. Which has vertical scale far exceeding terrestrial relief. The intensity and width of these currents depend on model parameters, notably the surface drag. From a comparison of our results with other martian models we suggest that WBCs have already been simulated, although they were not previously identified as such. The available observational evidence appears to be consistent with the presence of martian WBCs, which may be important in the generation of global and great dust storms

Atmospheric Dynamics of Terrestrial Planets

The solar system presents us with a number of planetary bodies with shallow atmospheres that are sufficiently Earth-like in their form and structure to be termed “terrestrial.” These atmospheres have much in common, in having circulations that are driven primarily by heating from the Sun and radiative cooling to space, which vary markedly with latitude. The principal response to this forcing is typically in the form of a (roughly zonally symmetric) meridional overturning that transports heat vertically upward and in latitude. But even within the solar system, these planets exhibit many differences in the types of large-scale waves and instabilities that also contribute substantially to determining their respective climates. Here we argue that the study of simplified models (either numerical simulations or laboratory experiments) provides considerable insights into the likely roles of planetary size, rotation, thermal stratification, and other factors in determining the styles of global circulation and dominant waves and instability processes. We discuss the importance of a number of key dimensionless parameters, for example, the thermal Rossby and the Burger numbers as well as nondimensional measures of the frictional or radiative timescales, in defining the type of circulation regime to be expected in a prototypical planetary atmosphere subject to axisymmetric driving. These considerations help to place each of the solar system terrestrial planets into an appropriate dynamical context and also lay the foundations for predicting and understanding the climate and circulation regimes of (as yet undiscovered) Earth-like extrasolar planets. However, as recent discoveries of “super-Earth” planets around some nearby stars are beginning to reveal, this parameter space is likely to be incomplete, and other factors, such as the possibility of tidally locked rotation and tidal forcing, may also need to be taken into account for some classes of extrasolar planet