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- Author or Editor: Paul Spyers-Duran 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
An intense rainstorm at Fremont, Mo., on July 28, 1964, yielded over 3 in. of rain in 30 min. and a total of 9.5 in. in 5 hr. The synoptic weather situation which was responsible for producing such an intense rain is discussed. Mass rainfall curves, a total storm isohyetal map, an area-depth curve, and a graph of rainfall rates, are presented. Computed updrafts in the clouds versus observed updrafts from radar data are discussed; the maximum cloud penetration height is compared with observed radar echo heights.
Abstract
An intense rainstorm at Fremont, Mo., on July 28, 1964, yielded over 3 in. of rain in 30 min. and a total of 9.5 in. in 5 hr. The synoptic weather situation which was responsible for producing such an intense rain is discussed. Mass rainfall curves, a total storm isohyetal map, an area-depth curve, and a graph of rainfall rates, are presented. Computed updrafts in the clouds versus observed updrafts from radar data are discussed; the maximum cloud penetration height is compared with observed radar echo heights.
Abstract
A comparison of sea surface temperatures is made between aircraft precision radiation thermometer (PRT-5) and aircraft deployed expendable bathythermographs (AXBT) drops. These observations were obtained using the NCAR King Air aircraft for an experiment in the Gulf of California during March 1984. The average difference between the sea surface temperatures reported by the first temperature observed in each AXBT drop and the PRT-5 is −0.07°C with a standard deviation of 0.57°C. The difference in temperature between the two observations increases at lower wind speeds. Based on 116 case studies, differences of 1–2°C exist between the surface and the upper meter of the ocean when wind speeds are less than 5 m s−1.
Abstract
A comparison of sea surface temperatures is made between aircraft precision radiation thermometer (PRT-5) and aircraft deployed expendable bathythermographs (AXBT) drops. These observations were obtained using the NCAR King Air aircraft for an experiment in the Gulf of California during March 1984. The average difference between the sea surface temperatures reported by the first temperature observed in each AXBT drop and the PRT-5 is −0.07°C with a standard deviation of 0.57°C. The difference in temperature between the two observations increases at lower wind speeds. Based on 116 case studies, differences of 1–2°C exist between the surface and the upper meter of the ocean when wind speeds are less than 5 m s−1.
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.
