ISOPRENE EMISSIONS FROM THE INNER MONGOLIA GRASSLAND

摘要

The volatile organic compound (VOC) emissions were measured by a static enclosure technique at a grassland site in the Inner Mongolia, China during the growing season in 2002. The parameters including solar spectral radiation, air temperature and relative humidity were also measured in the same time period. Isoprene exhibited an evident diurnal, daily and seasonal variation in 2002. Base on the correlation analysis, photosynthetically active radiation (PAR), air temperature and water vapor content were the main factors to control the process of isoprene emission, and PAR was the primary important factor. It is impossible to avoid the changes of solar radiation, temperature and humidity between inside and outside of the chamber by using the enclosure technique. So, it is necessary to take these effects into the considerations and modify isoprene emission. In summer 2002, the measured maximum emission flux of isoprene was 1649.3μg Cm~(-2)h~(-1), and monthly averaged emission flux in June, August and September were 886.6, 707.0 and 427.2 μgCm~(2)h~(-1), respectively.