油松林的能量平衡

THE ENERGY BALANCE OF A STAND (PINUS TABULAEFORMIS CARR)

根据实测资料,本文利用梯度观测方法,以波文比——能量平衡方程为基础,对黄土残塬区(山西吉县)一片油松人工林的能量平衡规律和蒸散量进行了分析和研究。结果表明,晴天油松林热量和净辐射收入丰富。蒸散耗热和湍流热交换占净辐射收入的86.2％,平均波文比为0.5500,土壤热通量约占净辐射收入的13.4％。晴天油松林蒸散水量8月份平均约5.1mm/d,4月、5月份平均约3.4mm/d,10月份平均约2.3mm/d,明显大于空旷地,呈秋季小于春季,春季又小于夏季的趋势。

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.