2019 Fiscal Year Annual Research Report
Oscillations of the Venus Climate System
| Project/Area Number |
18F18316
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
今村 剛 東京大学, 大学院新領域創成科学研究科, 教授 (40311170)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KOPPARLA PUSHKAR 東京大学, 新領域創成科学研究科, 外国人特別研究員
|
|---|
| Project Period (FY) |
2018-10-12 – 2020-03-31
|
| Keywords | Venus / climate / variability |
|---|
| Outline of Annual Research Achievements |
a. Intra-Annual Albedo Variability
I studied how changing albedo patterns on Venus are related to the dynamics and chemistry of the atmosphere. I used Venus dayside images from Akatsuki's UV Imager. Each dataset was subjected to a principal component analysis to find the most important modes of variability. The spatial patterns and the timescales of some of these modes correspond to known physical processes in the atmosphere of Venus such as the 4-day Kelvin wave, 5-day Rossby waves, and the overturning circulation, while some others defy a simple explanation. I have thus been able to breakdown the albedo variability into known and unknown dynamics and estimated what fraction of variability can be attributed to each dynamical mode.
b. Decadal Trace Gas Variability
Sulfur dioxide abundances at the cloud-top of Venus have been observed to oscillate on interannual to decadal timescales but the causes are unknown. I am proposing a new conceptual model to explain this occurrence. The water abundance at the base of the clouds, has a strong influence on the cloud-base heating and cloud level convection. The cloud level convective mixing in turn determines the gradient of water abundance in the atmosphere, and thereby the cloud-base water abundance. Thus, the convection and water abundance form a coupled system which oscillates on interannual to decadal timescales, which can explain the timescale of variability in the transport of sulfur dioxide to the cloud tops. This model will represent a fundamental advance of our understanding of long-term atmospheric variability on Venus.
|
| Research Progress Status |
令和元年度が最終年度であるため、記入しない。
|
| Strategy for Future Research Activity |
令和元年度が最終年度であるため、記入しない。
|
-
[Journal Article] Spatial and temporal variability of the 365-nm albedo of Venus observed by the camera on board Venus Express2020
Author(s)
Lee, Y. J., Kopparla, P., Peralta, J., Schroder, S. E., Imamura, T., Kouyama, T. & Watanabe, S.
-
Journal Title
JGR Planets
Volume: in press
Pages: in press
Peer Reviewed / Int'l Joint Research
-
-
[Presentation] Principal Components of UV Albedo Variability in Venus' Atmosphere as seen at 283 nm2019
Author(s)
Kopparla, P., Lee, Y. J., Imamura, T., & Yamazaki, A.
Organizer
JPGU Meeting 2019, Makuhari, Chiba, Japan
Int'l Joint Research
-
