HR: 14:25h
AN: P23E-04 INVITED     [Abstracts]
TI: Venus' Nightside Near-Infrared Thermal Radiation: Windows for Sensing Venus' Surface
AU: * Hashimoto, G L
EM: george@kobe-u.ac.jp
AF: Kobe University, Lab. Atmosphere-Hydrosphere Sciences, Kobe, 657-8501 Japan
AU: Roos-Serote, M
P23E-04 AF: Lisbon Astronomical Observatory, Tapada da Ajuda, Lisboa, 1349-018 Portugal
AU: Sugita, S
P23E-04 AF: University of Tokyo, Graduate School of Frontier Science, Kashiwa, 277-8561 Japan
AB: Venus' surface can be observed remotely on Venus' nightside using several windows in the near-infrared wavelength range. Although Venus is always shrouded in thick clouds, within the window thermal radiation emitted from the planetary surface penetrates through the thick atmosphere and clouds. To obtain the information on the surface, it is necessary to correct the effects of temporal and spatial variability in cloud transmittance by simultaneous observations at neighboring near-infrared windows and radiative transfer modeling, since scattering by clouds cannot be neglected in the Venus near-infrared windows. The intensity of thermal emission is controlled by the emissivity and temperature of the surface. Since the temporal variation in the temperature in the venusian lower atmosphere is expected to be small, the surface temperature will be approximated as the atmospheric temperature at the same elevation, which is calculated as a function of the altitude. Then, we will be able to estimate the surface emissivities at near-infrared wavelengths. If active volcanoes are erupting hot lavas, we will observe excess radiations. Due to strong dependence of the intensity of thermal emission on temperature, a lava lake formed in the crater of an active volcano as small as 1 km² will be readily detected.
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6295 Venus
SC: Planetary Sciences [P]
MN: Fall Meeting 2005