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2002 Annual Science Report

Virtual Planetary Laboratory (JPL/CalTech) Reporting  |  JUL 2001 – JUN 2002

Characterization of Terrestrial Planets From Disk-Averaged Spectra

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

This project uses spatially resolved spectral models of planets in our own solar system to determine the instrument sensitivity and spectral resolution required to detect signs of habitability or life in astronomical spectra of extrasolar planets. To do this we are creating a versatile computer model that takes user specifications of observer vantage point, solar illumination geometry, spectral and spatial resolution, and wavelength range to produce high-resolution, spatially resolved spectral simulations of Earth, Mars, Venus and Titan. The three-dimensional (3-D) ?datacube? of synthetic spectra generated will be used to determine the effects of spatial and spectral averaging and temporal variability on the detectability of biosignatures, and other spectral features that provide important constraints on a planet’s physical and chemical state, and its potential for habitability.

To start this project, we have been working to get SMART (our radiative transfer model for the generation of synthetic spectra) running on the Jet Propulsion Laboratory (JPL) ultracomputing facilities. We have started the model construction with Mars, which has large spatial variations in temperature, and readily available surface and atmosphere data. Mars surface albedos have been derived from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES), and the atmospheric thermal structure and surface pressure have been derived from the Ames Mars General Circulation Model (MGCM) simulations. We have completed coding of the geometrical components of the model, including manipulation of viewing geometry and solar illumination, and interpolation of synthetic spectra. We are in the process of generating the database of synthetic spectra for the Mars model. And will continue to work on this effort, and the Earth, Venus and Titan models in the coming year.

As an experimental validation component, our collaborators have acquired high-resolution full-disk spectra of Mars using the Fourier Transform Spectrometer on the Canada France Hawaii Telescope. In collaboration with the Australian Center for Astrobiology, we are also planning simultaneous optical and infrared validation observations of Venus.