(Proposal ID) S16B-021

(PI) Sato, Takao

(Proposal Title)
Coordinated observation of Venus cloud top with Subaru and AKATSUKI

(Abstract)
We request one run of four sequential first half nights observation using 
COMICS in January 5-19, 2017, to investigate the cloud top structure of Venus 
during the continuous observations by the Japanese Venus orbiter AKATSUKI. 
A series of spatially consecutive N-band low-resolution spectra in the entire 
disk of Venus will be observed to constrain the atmospheric temperature in 
60-70 km altitudes (cloud top) and vertical scale height of upper cloud 
opacity, which are key parameters to understanding the thermal balance of 
Venus. The latitudinal variation and local time dependence of the retrieved 
atmospheric parameters will provide indispensable complementary information to 
investigate the origin of the cloud top features seen in the 10-mum images by 
the AKATSUKI-onboard camera named LIR. The 8.6-mum and 11.2-mum narrow-band 
COMICS images are also captured to study how the atmospheric waves have an 
impact on the brightness temperature distributions in both the polar regions, 
together with the LIR images and recent numerical simulations. This work is 
timely and crucial to enhance scientific results of AKATSUKI, because no 
spectroscopic instrument is on-board the spacecraft and only COMICS can 
provide images whose spatial resolution is comparable to that of LIR.