Permalink : http://hdl.handle.net/2115/45152

JaLCDOI : 10.14943/gbhu.74.57

Venus has numerous cloud features caused by unknown UV absorber in ultraviolet light. Horizontal wind velocities have been derived by tracking those features in order to examine the atmospheric circulation such as superrotation. However, the generation mechanism is not well understood yet, because the altitude of the winds is ambiguous. Ignatiev et al. (2009) performed radiative transfer calculations and showed that the cloud top altitudes in 1.51μm wavelength are 74±1km in low and middle latitudes and 63-67km in polar region, respectively. They investigated also the correlation between the cloud top altitude in UV wavelength and that in infrared, and found that those cloud top altitudes are almost same in low and middle latitudes under the assumption of constant scale height of the cloud. In this paper, we propose a fully geometrical method using 3 images to derive cloud height and wind velocities simultaneously. The cloud height and wind velocities estimated by this method are similar to other results.