Recent results on the Venusian atmosphere from the Akatsuki mission

JAXA’s Venus orbiter Akatsuki arrived at Venus in December 2015, and has been continuously observing cloud movements and atmospheric structures from its elongated equatorial orbit. The onboard observation instruments are five cameras for different wavelengths from infrared to ultraviolet regions, and an ultra-stable oscillator for radio occultation experiments. The cameras have provided unprecedented continuous dataset of cloud images, allowing for a variety of meteorological analyses. Vertical sounding by radio occultation provides complementary information. Atmospheric processes that have been studied include variation in superrotation, angular momentum transport by planetary-scale waves, topographically generated waves, gravity wave breaking, thermal tides, long-term changes in cloud albedo, streaky clouds at high latitudes, and planetary-scale cloud discontinuities. In this talk, I will summarize recent results and discuss remaining issues.