Evidence of wintertime CO₂ emission from snow-covered grounds in high latitudes

In order to measure CO₂ flux in wintertime arctic ecosystems, CO₂ gas was sampled from various snow-covered grounds by using a closed chamber method during the First China Arctic Scientific Expedition from March to May in 1995. The CO₂ gas samples were measured by using an infra-red analyzer (IRGA). The results showed that (i) CO₂ emission was detected from all kinds of the snow-covered grounds, which provides direct evidence that the arctic tundra is functioning as a source of atmospheric CO₂; (ii) CO₂ release was also detected from the permanent ice profile and icecap, and (iii) CO₂ evolution from terrestrial ecosystems in higher latitudes increased with an increase of surface temperature in accordance with the exponential function. This indicates a close coincidence with that under normal temperature conditions, and provides a useful method for predicting change in CO₂ flux in the arctic ecosystems with the global climate change.