EFFECTS OF CONVERSION ALGORITHMS ON REPORTED UPPER-AIR DEWPOINT DEPRESSIONS

Different nations use different algorithms or other techniques to conv ert temperatures and relative humidities from radiosonde observations to dewpoint depressions. Thus, it is possible for identical measured v alues to result in different reported dewpoints. On the basis of a sam ple of conversion methods, we calculate the possible differences among the national practices. In general, the discrepancies are not large a nd would often be lost in the usual round-off procedures associated wi th transmission over the Global Telecommunications System, but in cold , dry conditions dewpoints different by more than 1-degrees-C could be reported for identical conditions. Some of the methods have been chan ged over time, so there is also the possibility of inhomogeneities in climate records.