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Disk-averaged Spectra & light-curves of Earth

G. Tinetti·V. S. Meadows·D. Crisp·W. Fong·N. Kiang·E. Fishbein·T. Velusamy·E. Bosc·M. Turnbull
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Abstract

We are using computer models to explore the observational sensitivity to changes in atmospheric and surface properties, and the detectability of biosignatures, in the globally averaged spectra and light-curves of the Earth. Using AIRS (Atmospheric Infrared Sounder) data, as input for atmospheric and surface properties, we have generated spatially resolved high-resolution synthetic spectra using the SMART radiative transfer model, for a variety of conditions, from the UV to the far-IR (beyond the range of current Earth-based satellite data). We have then averaged over the visible disk for a number of different viewing geometries to quantify the sensitivity to surface types and atmospheric features as a function of viewing geometry, and spatial and spectral resolution. These results have been processed with an instrument simulator to improve our understanding of the detectable characteristics of Earth-like planets as viewed by the first generation extrasolar terrestrial planet detection and characterization missions (Terrestrial Planet Finder/Darwin and Life finder). The wavelength range of our results are modelled over are applicable to both the proposed visible coronograph and mid-infrared interferometer TPF architectures. We have validated this model against disk-averaged observations by the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES). This model was also used to analyze Earth-shine data for detectability of planetary characteristics and biosignatures in disk-averaged spectra.

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G. Tinetti, V. S. Meadows, D. Crisp, W. Fong, N. Kiang, E. Fishbein, T. Velusamy, E. Bosc, M. Turnbull. 2005-02-11. Disk-averaged Spectra & light-curves of Earth. https://arxiv.org/abs/astro-ph/0502238

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