Publication Date:
2018-03-06
Description:
The paper is devoted to the investigation of Venus mesosphere circulation at 90-110 km altitudes, where tracking of the O 2 (a 1 Δ g ) 1.27μm nightglow is practically the only method of studying the circulation. The images of the nightglow were obtained by VIRTIS-M on Venus Express over the course of more than two years. The resulting global mean velocity vector field covers the nightside between latitudes 75°S – 20°N and local time 19 h – 5 h. The main observed mode of circulation is two opposite flows from terminators to midnight, however the wind speed in the eastward direction from the morning side exceeds the westward (evening) by 20-30 m/s, and the streams “meet” at 22.5±0.5 h. The influence of underlying topography was suggested in some cases: above mountain regions flows behave as if they encounter an "obstacle" and "wrap around" highlands. Instances of circular motion were discovered, encompassing areas of 1500-4000 km.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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