Search Results
You are looking at 1 - 4 of 4 items for
- Author or Editor: Keiji Higuchi x
- Refine by Access: All Content x
Abstract
A three-dimensional study of cumulus clouds was made by the use of aerial photographs of the clouds and their shadows. The side views of the clouds were obtained from photographs taken from an aircraft at a height slightly above cloud base level. Plan views were estimated from the rectified shapes of the cloud shadows. The map position of the clouds and height of cloud base were determined from the map position of their shadows and the. direction of the sun, by the use of Fujita' technique of single image photogrammetry. It was found that the long axis of flat cumulus cloud showed an apparent rotation in a wind field turning with height. In the case of fairly deep cumulus clouds, the forward edge of their upper part moved in the same direction and with nearly the same speed as the wind at the man level of the clouds; the forward edge of their lower part moved with the wind at the cloud base level but with a lower speed. The formation of new cumulus towers was observed on the up-shear side of the clouds.
Abstract
A three-dimensional study of cumulus clouds was made by the use of aerial photographs of the clouds and their shadows. The side views of the clouds were obtained from photographs taken from an aircraft at a height slightly above cloud base level. Plan views were estimated from the rectified shapes of the cloud shadows. The map position of the clouds and height of cloud base were determined from the map position of their shadows and the. direction of the sun, by the use of Fujita' technique of single image photogrammetry. It was found that the long axis of flat cumulus cloud showed an apparent rotation in a wind field turning with height. In the case of fairly deep cumulus clouds, the forward edge of their upper part moved in the same direction and with nearly the same speed as the wind at the man level of the clouds; the forward edge of their lower part moved with the wind at the cloud base level but with a lower speed. The formation of new cumulus towers was observed on the up-shear side of the clouds.
Abstract
The calculations of the probability of coalescence between two plane snow crystals is described in detail. As the result of calculation, it was concluded that this probability is minimum when two crystals are of the same size, the probability increasing with the difference in size.
Being concerned with the distance between the centers of two combined plane crystals, the author found that the most probable value was about a quarter of the sum of the diameters of two crystals.
Abstract
The calculations of the probability of coalescence between two plane snow crystals is described in detail. As the result of calculation, it was concluded that this probability is minimum when two crystals are of the same size, the probability increasing with the difference in size.
Being concerned with the distance between the centers of two combined plane crystals, the author found that the most probable value was about a quarter of the sum of the diameters of two crystals.
Abstract
A simple method has been devised for taking shadow photographs of snow crystals, or of their melt water, without use of a lens. It permits study of the form, size, and mass characteristics at intervals of several minutes during a snowfall. As an application of the method, the coalescence of crystals was studied. From the size distribution of crystals, the probabilities of coalescence between two crystals of the same size and of differing sizes were determined during a snowfall consisting of plane dendritic crystals.
Abstract
A simple method has been devised for taking shadow photographs of snow crystals, or of their melt water, without use of a lens. It permits study of the form, size, and mass characteristics at intervals of several minutes during a snowfall. As an application of the method, the coalescence of crystals was studied. From the size distribution of crystals, the probabilities of coalescence between two crystals of the same size and of differing sizes were determined during a snowfall consisting of plane dendritic crystals.
Abstract
The ice forming ability of solid particles was tested at −2 to −3C after first cooling them to −35 to −78C. During the cooling process, the water vapor pressure over the solid particles was kept below ice saturation, in order to avoid any ice formation on them. All of the treated samples of nine test materials showed ice-forming ability at −2 or −3C which is much warmer than their ordinary threshold temperatures. This ability was lost after warming above 0C.
Abstract
The ice forming ability of solid particles was tested at −2 to −3C after first cooling them to −35 to −78C. During the cooling process, the water vapor pressure over the solid particles was kept below ice saturation, in order to avoid any ice formation on them. All of the treated samples of nine test materials showed ice-forming ability at −2 or −3C which is much warmer than their ordinary threshold temperatures. This ability was lost after warming above 0C.
