There is a readme available for using the CM systems, view it in html or download a MSWord document. The document describes the functionality of the CM system but is not in final format. It is defined as the square root of the sum of all random errors squared plus the square root of the sum of all bias errors squared. The errors are assumed to be statistically independent. All CM uncertainty analyses are based on manufacturer's specifications.
Manufacturers specify accuracies in several ways.
Some give absolute range of error, some give uncertainties as defined above, while others give rms errors. In this analysis, rms errors are multiplied by 2. The long-term stability is not known. Errors considered in this accuracy are calibration uncertainty, repeatability, hysteresis, temperature dependence, and long-term stability over a period of one year. The CM determines the ambient dew point by chilling a mirrored surface to until dew droplets form on the mirror surface.