Abstract
Eddy correlation method is one of the useful methods to measure latent heat flux and sensible heat flux in the atmospheric surface layer. The necessary performances of the measurement system are 10Hz changes of specific humidity, vertical wind speed and air temperature, respectively. In order to measure specific humidity, a near infrared hygrometer using 1.37μm absorption band of water vapor was newly developed and evaluated in the grass field with a commercial near infrared hygrometer and an ultrasonic anemometer. We also discussed on frequency dependence of heat flux.
