Abstract
This article discusses common features of photosynthetically active radiation (PAR) in the Mongolian grain farm region during the period of 1986 to 1996. The quantitative characteristics of solar radiation, such as direct, diffuse and global radiation are evaluated in the study through the long term trend.
The mean pattern of seasonal variation of PAR shows that the yearly minimum global (direct+diffuse) PAR is 68.9±7.6MJ/(m2 month) in December while the maximum is 307.5±10.3MJ/(m2 month) in May. The yearly summation is 2.22±0.07GJ/(m2yr) and is very stable compared with monthly variations.
