Accession Number : AD0685031

Title :   RAINDROP DISTRIBUTIONS NEAR FLAGSTAFF, ARIZONA.

Descriptive Note : Final rept. 12 May 67-11 May 68,

Corporate Author : ILLINOIS STATE WATER SURVEY URBANA

Personal Author(s) : Jones,Douglas M. A.

Report Date : JAN 1969

Pagination or Media Count : 57

Abstract : The Illinois State Water Survey raindrop camera was operated from 9 July through 19 August 1967 at the Fort Valley Experimental Forest near Flagstaff, Arizona, before, during, and after a period of cloud seeding. Drop-size distributions were determined for showers which were seeded and unseeded and showers with and without the occurrence of hail. It was found, on the average, that seeded showers and natural showers forming in more humid air masses have fewer large drops and more drops per cubic meter for the same rainfall rate than have showers accompanied by hail and unseeded showers forming in relatively dry air masses. The increase in the relative number of drops at rainfall rates greater than 30 mm hr was investigated and found to be the result of the breakup of drops larger than 2.0 mm diameter. It is concluded that the peculiarity of the Flagstaff distributions lies in the extraordinary number of very large drops which fall in showers forming in relatively dry air and that these large drops do not break up easily because they are the remnants of hailstones. (Author)

Descriptors :   (*RAINDROPS, ARIZONA), DISTRIBUTION, PARTICLE SIZE, ARTIFICIAL PRECIPITATION, HAIL, DROPS, AIR MASS ANALYSIS, THUNDERSTORMS, EVAPORATION, RAINFALL, NETWORKS

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE