An Experimental Study of the Freezing of Drops in Free Fall.
Abstract
One process to explain natural ice pellets in the atmosphere is the heterogeneous freezing of large cloud drops. These experiments show that this process is of little importance. Drops of about 180 micrometer diameter which fell through high concentrations of aerosol nucleating particles showed consistantly very low percentages of freezes. From the information gathered a temperature threshold for lead iodide and phloroglucionol of -10C. and -6C respectively was determined. Also a dependence on the relative humidity of the air in the vicinity of particle collection was observed. This gave rise to relative humidity thresholds of 65% for lead iodide and 75% for phloroglucionol. The nucleating ability of airborne ice crystals was experimentally tested and found to be much lower than expected. This difference is attributed to a collection efficiency for drops collecting non-spherical ice crystals, which is much lower than a calculated collection assuming the ice to be spherical. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1974
- Accession Number
- AD0776390
Entities
People
- Marc L. Pitchford
- Thomas E. Hoffer
Organizations
- University of Nevada, Reno