Humidity required for ice-nucleation from the vapor onto silver iodide and lead iodide aerosols over the temperature range -6 to - 67degrees C.

Abstract

The ice saturation ratio at which 1% of aged silver iodide and lead iodide aerosol particles nucleate ice from moist air is observed to depend on temperature. Between roughly -30 and -67degrees C the threshold for both aerosol types rises slowly with decreasing temperature in agreement with a simple classical nucleation theory. Between -6 and -30degrees C the threshold for the silver iodide aerosol rises more rapidly than predicted by simple theory while the threshold for lead iodide decreases.-Authors