Exoclimes_Conference_booklet1

planets are now available, constrained by many new observations and measurements.
Here we analyse the global transfers of energy within the climate systems of a range of
terrestrial planetary bodies within the Solar System, including Mars, Titan and Venus, as
simulated by relatively comprehensive numerical circulation models. These results will
then be presented in schematic form for comparison with the “classical” global energy
budget analysis of Trenberth et al. for the Earth, highlighting the important similarities and
differences. We also consider how to extend this approach towards other Solar System
and extra-solar planets, including Jupiter, Saturn and hot Jupiter exoplanets.
A ~0.1 bar Rule for Tropopause Temperature Minima in Thick Atmospheres of
Planets and Large Moons
Tyler Robinson — University of Washington
Tropopause temperature minima are fundamental for understanding planetary atmospheric
structure. Inversions in the stratospheres of Earth, Jupiter, Saturn, Titan, Uranus, and
Neptune lead to temperature minima that, remarkably, all occur near 0.1 bar, despite very
different insolation, atmospheric composition, gravity, and internal heat flux. We have
explored this common 0.1 bar tropopause using an analytic 1-D radiative-convective
model. We find that tropopause temperature minima always lie in the radiative regime,
above the radiative-convective boundary. Thus, the shared 0.1 bar tropopause arises from
the common physics of radiative transfer. Model fits to solar system worlds show that the
gray infrared optical depth where the tropopause minimum occurs is ~0.1. Furthermore,
the gray infrared optical depths at a pressure of 1 bar are typically of order a few. These,
along with a commonly used power-law scaling between pressure and optical depth, set
the tropopause pressure at ~0.1 bar. Moving beyond the solar system, we show that the
typical gray infrared optical depth of the tropopause minimum is ~0.1 for a wide range of
plausible atmospheric compositions. This optical depth marks the transition into an upper
region of an atmosphere that is very transparent to thermal radiation. Here, shortwave
absorption can dominate the temperature profile and, thus, create an inversion and
corresponding temperature minimum. These findings imply that the common 0.1 bar
tropopause levels seen in the solar system atmospheres are more universal. Thus, we
hypothesize that many exoplanets will possess a 0.1 bar tropopause temperature
minimum.
Measurement of the atmospheres of Europa, Ganymede, and Callisto
Peter Wurz — Physics Institute, University of Bern!
The regular Jovian satellites are believed to be formed at the end of Jupiter's formation
epoch, from the collisional accretion of solids originating in the Solar Nebula, and captured
in a disk orbiting around the planet. The solids taking part to the formation of the satellites
therefore originate from the initial protoplanetary disk, and have probably experienced
lower temperature and pressure conditions as has the material incorporated in Jupiter, and
their chemical composition has been probably less altered. By measuring the composition
of the Jovian satellites, it is therefore possible to set constraints on the chemical
composition of building blocks of planets and satellites, and ultimately on the
thermodynamical conditions in the Solar Nebula.
The Particle Environment Package (PEP) suite has been selected for the JUICE mission
of ESA, which contains instruments for the comprehensive measurements of electrons,
ions and neutrals. One of the instruments is the Neutral and Ion Mass spectrometer
instrument (NIM). NIM is a time-of-flight neutral gas and thermal ion mass spectrometer
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