Investigation of the radiative energy balance of Venus based on improved models of the middle and lower atmosphere

• Applicant: Dr. Rainer Haus
• Subject Area: Atmospheric Science
• Term: from 2012 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 225438391

The research proposal aims to investigate the radiative energy balance of Venus in the middle and lower atmosphere (90-0 km). Novel retrieval techniques will be applied for this purpose that facilitate a derivation of improved models of atmospheric temperature fields, cloud features, and trace gas distributions.The proposed work is based on analyses of radiation measurement data that were recorded by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard ESA’s Venus-Express mission in the near-infrared spectral region. As supplement to the database for the thermal infrared region, it is also intended to use Fourier spectrometer measurements aboard the Russian Venera-15 experiment (1983). The applicant is/was involved in the two experiments as Co-Investigator and has unrestricted data access. The methods for derivation of improved atmospheric models will simultaneously utilize various transparency windows on the nightside of the planet (multi-window use) that yield information on atmospheric features in the altitude range 0-90 km. New and in preparatory work developed and verified radiative transfer models will be employed for this purpose that consider the extreme environmental conditions of the dense lower atmosphere and that clearly differ from conventional models. Novel retrieval methods, which are based hereupon and which have been already successfully verified to some extent, will allow for the simultaneous use of a large number of spectra (multi-spectrum use). They are able to separate influences of the atmospheric parameters temperature, cloud, and trace gas distribution on measured spectra, and to quantify the parameters themselves. Beyond that, these techniques shall facilitate for the first time the determination of wavelength-dependent atmospheric continuum absorption, the strong influence of which on the atmospheric transparency windows was not sufficiently considered by currently available models. The accuracy of retrieved atmospheric parameters can be substantially enhanced thereby. This Venus research project combines the utilization of the best ever available remote sensing data archive with the adaptation of novel sophisticated analysis methods to retrieve atmospheric state parameters. Derived multi-dimensional parameter maps will be subsequently used to calculate location and time-dependent net radiation fluxes in the middle and lower atmosphere and to study impacts of possible parameter variations. Altitude-dependent heating and cooling rates resulting from the vertical divergence of net fluxes will provide a new data base for the exploration of dynamical processes and global circulation mechanisms.

• DFG Programme: Research Grants
• Participating Persons: Professorin Dr. Gabriele Arnold; Dr. David Kappel