油松林的能量平衡

THE ENERGY BALANCE OF A STAND (PINUS TABULAEFORMIS CARR)

Based on the observation data made in April to October 1988, with the method of Bowen ratio-energy balance, a preliminary study and calculations on the energy balance and the mean evapotranspirtion ratio of a Pinus tabu-laeformis carr. stand was taken in this paper in Jixian county, Shanxi province. The results were obtained as follows.The radiation income of the stand is rich. The flux of evapotranspiration and turbulent heat exchange are 86.2% of the net radiation of the stand on average. The mean Bowen ratio is 0.5500. The energy consumed by soil heat exchange is 13.4%. The mean evapotranspiration ratio of the stand is 5.1mm/day in August, 3.4mm/day in April and May, 2.3mm/day in October. A tendency was found that evapotranspiration ratio in autumn is less than that in spring, and but that in summer is higher than that in spring.