15 - Calibration

Summary

Instrument calibrations are both one of the most important, and yet sometimes one of the most neglected, areas of weather measurement. This chapter describes straightforward methods to check and adjust calibrations for the most common meteorological instruments – precipitation (rainfall), temperature, humidity and air pressure sensors. To reduce uncertainty in the measurements themselves, meteorological instruments need to be accurately calibrated, or at least regularly compared against instruments of known calibration to quantify and adjust for any differences, or error. Calibrations can and do drift over time, and therefore instrumental calibrations should be checked regularly, and adjusted if necessary.