SOME LIMITATIONS AND ERRORS INHERENT IN THE USE OF THE DEW CELL FOR MEASUREMENT OF ATMOSPHERIC DEW POINTS

The physics of the dew cell sensor are investigated and the resulting limitations upon application and errors in use are discussed. Specific consideration is given to the measurable range of dew point temperatures and relative humidities, response at different temperatures and under different aspiration conditions, and to errors arising from change in the water of hydration of lithium chloride and from existing absolute humidity gradients. It is concluded that two major sources of difficulty exist with the dew cell: the choice of lithium chloride and the means of aspiration.