Engineering topics

Sax, R. I.

Publications and source records attributed to Sax, R. I..

3 records

NASA NTRS1982

Clarification of confirmation in the FACE-2 experiment

Definitions of the data acquisition and interpretation goals which were sought in the Florida Area Cumulus Experiment (FACE) phase-II experiment as confirmation of results from FACE-I are presented. The FACE-1 trials in cloud seeding to increase rainfall were conducted in 1970, '71, '73, '75, and '76 and phase II proceeded from June 1978-August 1980. The data from the second set were to be treated with a block randomization scheme using the mean vector wind speed and direction and superposition of rainfall data, considering fixed and floating target clouds. A first level of probability was configured to eliminate cells from further investigation, and then two other levels are included in the analyses, each of continually increasing levels of likelihood. The instances of rainfall with seeding cover periods of either 60 or more or 60 or less seeding flares being ignited.

Woodley, W. L.↗

NASA NTRS1981

Microphysical development of a pulsating cumulus tower - A case study

In-cloud microphysical data collected within a 22-minute period during seven consecutive passes at the -13 C sampling level of a deep (base +22 C) convective cloud provide observational evidence for a secondary ice production mechanism at work in the Florida environment. The observed microphysical characteristics of the convective tower, particularly the spatial distribution and habit of the ice phase relative to the updraft, are consistent with a rime-splintering hypothesis for secondary ice production. It is shown that the cloud's updraft structure is critically important in governing the timing of the ice production by controlling the flux of graupel particles through the critical temperature zone (-3 C to -8 C). The importance of the cloud's pulsation growth dynamics on the microphysics is emphasized, particularly as it relates to rapidly glaciating cumuli.

Keller, V. W.↗

NASA NTRS1980

Water-ice and water-updraft relationships near -10 C within populations of Florida cumuli

Evidence is presented for a sequential development of cloud water, rainwater, graupel, and crystalline ice with the aging of the cloud. This evidence is based on in-cloud microphysical data set collected in Florida convective towers that were penetrated close to their tops near -10 C; the very rapid onset of graupel that appears on repeat penetrations of some towers is of particular interest. A separate data set shows a large scatter in the relationship between the maximum value of cloud water and vertical velocity which indicates that measurements of cloud water can be misleading as an indication of growth activity. The sequential pass data showing the evolution of ice and water are consistent with a rime-splintering, secondary ice production hypothesis.

Sax, R. I.↗