Abstract
A small sonde system for measuring trace gas fluxes with the relaxed eddy accumulation method installed below a tethered balloon was developed. The system consists of mainly three parts: sensors, a microcomputer and a sampling unit. The sensors are a one-dimensional sonic anemometer for measuring the vertical wind component, a fine wire thermocouple thermometer for measuring the mean and fluctuations of temperature, and a cup anemometer for measuring mean wind speed. The microcomputer processes and stores the meteorological signals and also controls the apparatus with a BASIC program. Total weight including the gimbal system is 1.5kg. Preliminary measurements of the fluxes of sensible heat, CO2 and CH4 were carried out.
