Nucleation and Characteristics of Liquid Nitrogen

Abstract

This paper describes experiments on a refrigerating catalyst—liquid nitrogen (LN)—in different cloud chambers and their results. The nucleation threshold temperature of liquid nitrogen is 0°C, and when the temperature less than −2°C, the ice nucleation rate is about 1012 g−1. This indicates that LN can be employed in artificial precipitation enhancement and artificial supercooled fog dispersal activities. It is found in the experiments that in fogs with a temperature slightly above 0°C, liquid nitrogen can play a role of broadening the fog drop spectrum, increasing the number of big droplets and decreasing the number of small ones. In addition, the application of microvideo and IR technology in cloud chamber experiments is also described.