JpGU-AGU Joint Meeting 2017

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[EJ] Oral

P (Space and Planetary Sciences) » P-PS Planetary Sciences

[P-PS06] [EJ] Results of Venus science with Akatsuki in orbit for 1.5 year

Sat. May 20, 2017 1:45 PM - 3:15 PM Convention Hall B (International Conference Hall 2F)

convener:Takehiko Satoh(Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency), Takeshi Horinouchi(Faculty of Environmental Earth Science, Hokkaido University), Masaru Yamamoto(Research Institute for Applied Mechanics, Kyushu University), Kevin McGouldrick(University of Colorado Boulder), Chairperson:Takeshi Horinouchi(Faculty of Environmental Earth Science, Hokkaido University)

2:20 PM - 2:45 PM

[PPS06-13] Clouds' scattering property of Venus observed by UV imager on board Akatsuki

★Invited papers

*Yeon Joo Lee1, Manabu Yamada2, Atsushi Yamazaki1, Shigeto Watanabe3, Takeshi Imamura4, Takao Sato1, Kazunori Ogohara5 (1.ISAS/JAXA, 2.PERC/Chiba Institute of Technology, 3.Hokkaido Information Univ., 4.Univ. of Tokyo, 5.Univ. of Shiga Prefecture)

Keywords:Venus, Akatsuki, UV image, glory

The top altitude of the Venus cloud layer is around 70 km above the surface, at where solar radiation scattering occurs effectively. The scattering follows a phase curve depending on microphysical properties of cloud aerosols. We analyze global mean albedo obtained by the UV Imager (UVI) on board Akatsuki. Data acquired in May 2016 shows clear glory features at 283 and 365 nm at small phase angles. We successfully simulate the observation using a radiative transfer model. We estimate reff=1.26 um and veff=0.076 for mode 2 to explain the observation, consisting with a previously suggested low latitudinal aerosol property. We find that SO2 and the unknown UV absorber are necessary factors to explain the observed quick decreasing of albedo at phase angles larger than 10 degree. We suggest a range of possible SO2 abundance at 70 km from 80 to 400 ppbv, depending on assumed atmospheric conditions.