Changes in Absorption Coefficient of Krypton Hygrometer in Long-term Monitoring of Evapotranspiration and Its Calibration Using a Dew Point Generator

증발산 장기 관측에 따른 크립톤 습도계의 흡수 계수의 변화와 이슬점 생성기를 이용한 기기 보정

Calibrations of fast-response krypton hygrometers were carried out using a dew-point hygrometer to investigate the changes in their absorption coefficients due to long-term field operation. Absorption coefficients changed proportionally with the number of hours of field operation. The increase in absorption coefficient indicates that the water vapor flux, calculated with the original absorption coefficient, would underestimate the true flux in the field. To minimize the uncertainty in quantifying evapotranspiration and surface energy budget studies, frequent calibrations (for example, every 1500 hours of field operation) of krypton hygrometer are recommended.