Use of Temporal Variations of Radon Activities in Soil Gas Depth Profiles for Calibrating Trace Gas Exchange in Agro-Ecosystems

摘要

New sensitive radon monitors have been combined with a computer controlled gas sampling system for continuous activity measurements of ~(220)Rn at various altitudes above and below the surface. Air is extracted from semi-permeable membrane tubes of 1.5 m length placed at depths of 10, 25, 50 and 70 cm below the soil surface and from various heights within and above the canopy of a wheat field. The influence of meteorological and soil parameters on the vertical gas exchange between soil, vegetation and atmosphere is investigated.