Wave signature in the Venus dayside cloud layer at 58–64 km observed by ground-based infrared spectroscopy

We performed infrared spectroscopic measurements of the Venus’ dayside to find out atmospheric wave structures at 58–64 km in the cloud layer by quantifying carbon dioxide absorption. This is the first investigation of atmospheric waves at this altitude region. This effective absorption altitude lies in between that of 70 km by the ultraviolet measurements and of 50 km by the infrared thermal emission measurements. The apparent rotation periods of wave-like signature found are 3.5, 4.9 and 8.4 days, respectively, in May 2007, November 2007 and August 2010 assuming dominance of wavenumber one structure. Those apparent periods may be interpreted as superposition of the mean zonal flow and waves such as the Kelvin and the Rossby.