On the Cloud Height by Stereoscopic Observation Using Two Fish-Eye Lens Cameras in the Summer Season at Ayowa Station, Antarctica

Abstract

Cloud height, direction and velocity were measured by means of stereoscopic observation using two fish-eye lens cameras in the summer season of 1968 at Syowa Station, Antarctica. Although the method is somewhat uncertain in regard of observational and analytical errors, we can obtain the cloud height within a range of error of 10 percent if the location of the clouds for observation, is carefully selected, with the exception of the periphery and around the zenith of images of fish-eye lens photographs. The results of the analysis were as follows : In the case of Ci, Cc and Cs of high level clouds, the height was within a range of 5 to 8km ; in the case of Ac cloud at the middle level the height was within a range of 2 to 3km ; and in the Sc cloud at the low level the height was approximately 1km. These heights coincided in all cases with the cloud heights estimated from the sounding curves obtained by routine radiosonde observation. On the other hand, in comparison with the heights reported by routine naked eye observation, they coincided with the cases of Ac and Sc clouds alone, whereas, in the case of the high level clouds, the cloud heights were different from each other. The reported heights of the high level cloud by naked eye observation were in a range of 4 to 5km invariably. The calculated direction and velocity of each cloud based on the data observed by fish-eye lens cameras coincided closely with the direction and velocity at the same level estimated by the radiosonde observations. From these results the calculated cloud heights at all levels are considered reasonable, and it is concluded that the reported heights of the high level cloud by naked eye observation are comparatively lower. Cu and Cb clouds were not observed during this period.