Integrated ray tracing simulation of disk averaged spectral signatures from full 3D optical earth model
- Paper number
IAC-09.A1.5.4
- Author
Mr. Dongok Ryu, Global Space Optics Laboratory, Korea, Republic of
- Coauthor
Prof. Sug-Whan Kim, Global Space Optics Laboratory, Korea, Republic of
- Coauthor
Ms. Soomin Jeong, Global Space Optics Laboratory, Korea, Republic of
- Coauthor
Mr. Jae-Min Lee, University of Oxford, United Kingdom
- Coauthor
Mr. Jinsuk Hong, I&A Technology, Korea, Republic of
- Coauthor
Ms. Sun Jeong Ham, Global Space Optics Laboratory, Korea, Republic of
- Coauthor
Ms. Yukyeong Jeong, Global Space Optics Laboratory, Korea, Republic of
- Year
2009
- Abstract
Precise identification and understanding of disk averaged spectral signatures from extra terrestrial planets attract an increasing attention from both astronomy and space science communities in recent years. One of the most important scientific breakthroughs in this area of research would be to obtain the detailed understanding on disk averaged spectral signatures of the Earth. As we know that the Earth is the only known planet exhibiting the evidence of habitable biosphere, it serves as a reference datum for accurate interpretation of collapsed (in time and spatial domains) information from the spectral measurement using future Terrestrial Planet Finder missions instruments; TPF-C, TFP-I, or Darwin. We report a new Integrated Ray tracing model capable of computing various disk averaged spectral signatures of the Earth, as they are measured from remote observation point. The model includes the sun (i.e. light source), the full 3D optical earth and moon and an optical instrument (i.e. both an imager and a spectrograph), all combined into single ray tracing environment in real scale. In particular the light source models include the Sun and other standard of M, K stars. The full 3D optical earth surface is built using high resolution coastal line data and is further benefitted from realistic reflectance and BSDF characteristics depending on wavelength, and vegetation types and their distributions. The Moon surface is defined with the measured reflectance data obtained from the Clementine mission. We first examined the model validity with the broadband instrument imaging and radiometric performances computed from ray tracing, simulating earth observation from both L1 halo orbit and Moon orbit respectively. We first computed phase dependent light curves and NDVI indexes. We then used a low resolution spectrograph model and simulated the disk averaged spectral measurement of the Earth from various orbital configurations. The intensive simulation runs for various input conditions such as seasonal vegetation changes and variable cloud covers were performed. We present the computational details together with the simulation results in comparison with the Earthshine measurements and MGS-TES observation.
- Abstract document
- Manuscript document
(absent)