Planetary atmosphere observation analysis

Abstract:

The pointwise meteorological observations of the Viking Lander and Mars Pathfinder as well as the orbital mapping and sounding performed by, e.g., Mariner 9, Viking Orbiters and the Mars Global Surveyor have given a good understanding of the basic behaviour of the Martian atmosphere. However, the more detailed characterisation of the Martian circulation patterns, boundary layer phenomena and climatological cycles requires deployment of meteorological surface networks. The European NetLander concept comprising four well-instrumented landers is being studied for launch in 2005 and operations spanning at least a Martian year in 2006-2008. The landers are to be deployed to areas in both Martian hemispheres from equatorial regions to low mid-latitudes. The NetLander atmospheric instrument system (ATMIS) on board each of the landers is designed to measure atmospheric vertical profiles of density, pressure and temperature during the descent onto the surface, as well as pressure, atmospheric and ground temperatures, wind, atmospheric optical thickness and humidity through a full Martian year, possibly beyond. The main operational objective of this meteorological experiment is to provide a regular time series of the meteorological parameters as well as accelerated measurement campaigns. Such a data set would substantially improve our understanding of the atmospheric structure, dynamics, climatological cycles, and the atmosphere-surface interactions. The ATMIS sensor systems and measurement approaches described here are based on solutions and technologies tested for similar observations on Mars-96, Mars Pathfinder, Huygens, and Mars Polar Lander. Although the number of observation sites only permits characterisation of some components of the general circulation, the NetLander ATMIS will more than double the number of in situ vertical profiles (only three profiles - two from Viking Landers and one from Mars Pathfinder - are currently available and as envisioned at the time of writing, none of the 2001 and 2003 landers' payloads include entry phase measurements of pressure or temperature), perform the first in situ meteorological observations in the southern low- and mid-latitudes and provide the first simultaneous in situ multi-site observations of the local and general circulation patterns, in a variety of locations and terrains. As such, NetLander ATMIS will be the precursor of more comprehensive meteorological surface networks for future Mars exploration. © 2000 Elsevier Science Ltd. All rights reserved.

Abstract:

Mars, one of the most Earth-like of the planets, is today a cold, dry and barren world. However, there is good evidence that it may have been much warmer and wetter in the past and perhaps even supported life. The public interest aroused by these findings and by recent studies of 'SNC' meteorites, believed to have come from Mars, with their claims of the evidence of ancient Martian life, has focused attention on the ambitious programme of Mars Exploration currently being undertaken by NASA and ESA and has provided additional impetus. Improved measurements of the conditions on Mars' surface and in its atmosphere are central to both agencies' plans, and current atmospheric missions are reviewed in this paper together with possible future designs.

Abstract:

The understanding of the composition and cloud structure has advanced greatly in the last few years and in particular was greatly improved upon following the highly successful Pioneer and Voyager missions to that planet. Recently the Galileo spacecraft has gone into orbit about Jupiter and its remote sensing instruments, including the Near Infrared Mapping Spectrometer (NIMS) and the Solid State Imager (SSI), have yielded exciting new details of the spatial and vertical structure of the Jovian clouds and volatiles. At the same time Galileo's entry probe has made the first ever in situ measurements of conditions in the atmosphere. Recent ground-based observations have also added to the body of evidence from which conditions in the Jovian atmosphere may be inferred. This paper aims to review the current understanding of the composition and cloud structure of Jupiter's atmosphere in the light of the new Galileo results and recent ground-based, and earth-orbiting telescope observations.