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- Author or Editor: Paul Spyers-Duran x
- Journal of Applied Meteorology and Climatology x
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Abstract
Liquid water concentrations in cumulus clouds have been measured from an aircraft using the Johnson-Williams hot wire device. From simultaneous continuous cloud replicator records, liquid water contents have been computed from the observed drop size distributions. Comparisons between data from the hot wire and replicator devices indicate that both instruments are fairly accurate in measuring liquid water contents at least up to 3.5 gm m−3, with the closest agreement when the median volume diameter of the cloud droplets was under 30 μm.
Abstract
Liquid water concentrations in cumulus clouds have been measured from an aircraft using the Johnson-Williams hot wire device. From simultaneous continuous cloud replicator records, liquid water contents have been computed from the observed drop size distributions. Comparisons between data from the hot wire and replicator devices indicate that both instruments are fairly accurate in measuring liquid water contents at least up to 3.5 gm m−3, with the closest agreement when the median volume diameter of the cloud droplets was under 30 μm.
Abstract
Ice nuclei collected on Millipore filters were processed at −16.6°C water saturation and resulting crystals allowed to sublime. The filters were then reprocessed. Eighty-three percent of the original sites reactivated, 17% did not, but 12% of the new crystals were located on new sites.
Abstract
Ice nuclei collected on Millipore filters were processed at −16.6°C water saturation and resulting crystals allowed to sublime. The filters were then reprocessed. Eighty-three percent of the original sites reactivated, 17% did not, but 12% of the new crystals were located on new sites.
Abstract
During the summer of 1966 from Bemidji, Minn., aircraft collections of cirrus crystals were made with a continuous particle replicator. Actual samples show that cirrus crystal trails with a concentrations of 105–106 m−3 can survive a fall of 20,000 ft in clear air with a temperature/dew point spread of 15C. Computations of evaporation rates for falling crystals suggest that it is somewhat surprising that the crystals could have survived under the observed conditions; however, this may have been because input data for the calculations are inadequate.
Abstract
During the summer of 1966 from Bemidji, Minn., aircraft collections of cirrus crystals were made with a continuous particle replicator. Actual samples show that cirrus crystal trails with a concentrations of 105–106 m−3 can survive a fall of 20,000 ft in clear air with a temperature/dew point spread of 15C. Computations of evaporation rates for falling crystals suggest that it is somewhat surprising that the crystals could have survived under the observed conditions; however, this may have been because input data for the calculations are inadequate.
Abstract
On the basis of Millipore filter measurements it is concluded that natural ice nuclei were deactivated in passing over St. Louis, Mo., during March 1973. This conclusion is supported by very strong statistical evidence.
To overcome the effects of soluble materials in desensitizing the filter technique, samples were limited to volumes less than 100 liters with the background crystal count measured for every filter; a forced-flow developing chamber was used; and the Huffman-Vali correction factor, based upon concurrently measured CCN, was applied.
The measurements strongly suggest the possibility of local sources of ice nuclei. However, these nuclei also were deactivated in passing over the city.
Simultaneous measurements with an expansion chamber gave results similar to those of the filters, but did not show statistical support.
Abstract
On the basis of Millipore filter measurements it is concluded that natural ice nuclei were deactivated in passing over St. Louis, Mo., during March 1973. This conclusion is supported by very strong statistical evidence.
To overcome the effects of soluble materials in desensitizing the filter technique, samples were limited to volumes less than 100 liters with the background crystal count measured for every filter; a forced-flow developing chamber was used; and the Huffman-Vali correction factor, based upon concurrently measured CCN, was applied.
The measurements strongly suggest the possibility of local sources of ice nuclei. However, these nuclei also were deactivated in passing over the city.
Simultaneous measurements with an expansion chamber gave results similar to those of the filters, but did not show statistical support.
Abstract
An instrument for collecting cloud particles from an airplane has been developed. Cloud particles are captured and permanently replicated using the well known Formvar technique. From the continuous record of hydrometeor replicas, the forms, sizes and frequency distributions can be established. Description of the instrument and examples of data collected from natural clouds are presented. Problems of calibration are discussed.
Abstract
An instrument for collecting cloud particles from an airplane has been developed. Cloud particles are captured and permanently replicated using the well known Formvar technique. From the continuous record of hydrometeor replicas, the forms, sizes and frequency distributions can be established. Description of the instrument and examples of data collected from natural clouds are presented. Problems of calibration are discussed.
