Planetary Atmospheres

Credits: NASA, ESA, CSA, and L. Hustak (STScI)

Atmospheres, when present, are the outermost layer of cosmic bodies (read planets and satellites), within which the flux of energy from the correspondent star and its interaction with the components of the atmosphere itself configures the surface environment.
Being a fluid constituent, atmosphere is subjected to a complex dynamic of processes, chemical, thermodynamic and mechanical, at every different scale from the molecular to the global level.
On Earth, the importance of the better understanding of our atmosphere cannot be underrated, given its determinant role in the shaping of the climate and weather. On exoplanets, atmospheres are the only observable element when trying to characterize them, so the more accurately their atmospheres can be studied, the better can they be known.
The Group of Atmospheric Science develops radiative transfer and retrieval algorithms to study planetary atmosphere phenomena. In particular, we have developed the radiative transfer code FUTBOLIN (FUll Transfer By Optimized LINe-by-line). It allows generating high-resolution synthetic spectra in the 0.3-1000 micrometre spectral range. The code can handle spherical or plane-parallel atmospheres. It reads spectral lines in HITRAN or GEISA format and can handle CO2 and O2 line mixing and continuum absorption from H2O, O2, N2 and CO2. It also takes into account the Non Local Thermodynamic Equilibrium (NLTE) effects on the electronic and vibrational populations of the atmospheric species and allows to specify any combinations of clouds, coverage and spectral albedo. It has been used to model the Earth’s atmosphere, and the atmospheres of Mars, Venus, and Titan. The code can calculate reflection, transmission, absorption, infrared cooling rate, and flux spectra.