Quasi-Equilibrium Temperature Differences between Radiating Ice Crystals and the Surrounding Air

Abstract

A previous attempt to calculate the temperature gradient around a growing ice crystal in clear air started with the radiation budget of the crystal plus the assumption that the measured frost point temperature (about 2C below air temperature) represented the crystal temperature. When the conductivity equation for the air around the crystal is fully solved with the radiation budget as the boundary condition, however, it is found that less than 0.03C temperature difference can be sustained by radiative cooling of the crystals. The most probable explanation of the difference between the two approaches is that the humidity measurements are in error, and that the error has been generally recognized only at measured humidities in excess of 100%.