Search Results
You are looking at 31 - 40 of 57 items for
- Author or Editor: Louis J. Battan x
- Refine by Access: All Content x
Abstract
When employing radar for measuring rainfall rate, particularly for use in estimating the attenuation of radio waves, it is essential to take into account vertical air motions. An expression is derived to estimate, knowing the radar reflectivity, the rainfall rate-weighted, mean downward velocity of raindrops.
Abstract
When employing radar for measuring rainfall rate, particularly for use in estimating the attenuation of radio waves, it is essential to take into account vertical air motions. An expression is derived to estimate, knowing the radar reflectivity, the rainfall rate-weighted, mean downward velocity of raindrops.
In 1959, the author published a summary of cloud physics research reported in the Soviet literature during the period 1948 to 1957. At that time the amount of material dealing with radar meteorology and cloud modification was small. During the last two years more information on these two subjects has become available. This article summarizes the new material.
In 1959, the author published a summary of cloud physics research reported in the Soviet literature during the period 1948 to 1957. At that time the amount of material dealing with radar meteorology and cloud modification was small. During the last two years more information on these two subjects has become available. This article summarizes the new material.
Abstract
Data gathered by the Thunderstorm Project in Ohio during 1947, by use of a radar set AN/TPS–10, were analyzed to study the process of precipitation initiation in natural convective clouds. It is shown that about 60 per cent of all echoes first appeared at temperatures warmer than 0C. By use of RHI-data taken at intervals of time averaging about two minutes, the time history of precipitation in clouds was studied. Composite height vs. time curves show the rate of spread of the echoes. From these data it is concluded that, in middle latitudes, precipitation is frequently formed through a process involving only the liquid phase of water.
Abstract
Data gathered by the Thunderstorm Project in Ohio during 1947, by use of a radar set AN/TPS–10, were analyzed to study the process of precipitation initiation in natural convective clouds. It is shown that about 60 per cent of all echoes first appeared at temperatures warmer than 0C. By use of RHI-data taken at intervals of time averaging about two minutes, the time history of precipitation in clouds was studied. Composite height vs. time curves show the rate of spread of the echoes. From these data it is concluded that, in middle latitudes, precipitation is frequently formed through a process involving only the liquid phase of water.
The U.S.S.R. has a large investment in weather modification research and operations. Major cloud physics experimental facilities exist at the Institute of Experimental Meteorology and at the Institute of Geophysics of the Georgian Academy of Sciences. Hail suppression operations are being carried out over about 5 000 000 ha of farmland. Although claims of success in these activities are more modest than they were in 1969, it is still reported that the benefits far exceed the costs. There is relatively little research and, at this time, apparently only one small-scale operational program dealing with precipitation augmentation. Research in the Ukraine over the last three years has led scientists there to conclude that ice nuclei seeding of cumulonimbus clouds, over a substantial area, caused rainfall increases of about 30%. It also was reported that snow from frontal clouds was increased.
The U.S.S.R. has a large investment in weather modification research and operations. Major cloud physics experimental facilities exist at the Institute of Experimental Meteorology and at the Institute of Geophysics of the Georgian Academy of Sciences. Hail suppression operations are being carried out over about 5 000 000 ha of farmland. Although claims of success in these activities are more modest than they were in 1969, it is still reported that the benefits far exceed the costs. There is relatively little research and, at this time, apparently only one small-scale operational program dealing with precipitation augmentation. Research in the Ukraine over the last three years has led scientists there to conclude that ice nuclei seeding of cumulonimbus clouds, over a substantial area, caused rainfall increases of about 30%. It also was reported that snow from frontal clouds was increased.
This article gives a condensed summary of cloud-physics research carried on in the USSR during the last ten years. An extensive bibliography, with sources of translations, is also given.
This article gives a condensed summary of cloud-physics research carried on in the USSR during the last ten years. An extensive bibliography, with sources of translations, is also given.
Abstract
No Abstract Available
Abstract
No Abstract Available
Abstract
Polarization and vertical velocity of angel echoes were measured by means of a vertically pointing Doppler radar. Resulting analysis showed that most often the depolarization was between −9 and −15 db. A mean depolarization of −10.3 db was calculated. If the scattering were from randomly oriented, uniform, prolate water spheroids, this depolarization would correspond to an axial ratio of 2.8. Vertical velocities were initially negative (downward), but became positive during the time period of cumulus development directly above the radar. Radar cross sections ranged from 8.0 × 10−5 to 1.3 × 10−1 cm2.
Abstract
Polarization and vertical velocity of angel echoes were measured by means of a vertically pointing Doppler radar. Resulting analysis showed that most often the depolarization was between −9 and −15 db. A mean depolarization of −10.3 db was calculated. If the scattering were from randomly oriented, uniform, prolate water spheroids, this depolarization would correspond to an axial ratio of 2.8. Vertical velocities were initially negative (downward), but became positive during the time period of cumulus development directly above the radar. Radar cross sections ranged from 8.0 × 10−5 to 1.3 × 10−1 cm2.
