Comparison of Aerological Soundings made Simultaneously by Radio-Sonde and Aircraft

On five separate occasions soundings were made at the same time by Väisälä radio-sonde and by an aircraft equipped with electrical resistance thermometers. Display of the results leads to the conclusion that the temperature indicated by the radio-sonde was too high by an amount which usually was between 1 and 1½°C, but occasionally reached 2½ to 3½°C. The usual difference can be accounted for by the known effects of lag and radiation error, and it is recommended that even in the lower troposphere appropriate corrections should be made as a routine in conditions of sunny weather and steep lapse rate. Because of the excessive lag often shown by the radio-sonde hygrometer unit (of hair), shallow layers of very dry air are not indicated at all in the radio-sonde soundings.