贡嘎山暗针叶林区森林蒸散发特征与模拟

通过对贡嘎山森林区的蒸发实验观测,利用修正的Penman-Monteith公式对地面和冷杉林蒸散进行模拟,并与水面实际观测资料进行对比。结果显示:控制该区蒸散的主导因子是太阳有效辐射、大气温度以及植被类型;对裸地、灌草、森林模拟的年内变化过程与水面蒸发的实际观测值趋势一致,分别在4月和9月出现两个明显的蒸发高峰。原始Penman公式可以用于裸露地面和短草地面的蒸发计算,然而对森林蒸散发应采用Penman-Monteith公式模拟,其模拟结果显示,在非生长季节森林蒸散发低于非森林地面,而在森林生长季节的蒸散发比非林地要高,其变化差异在±25%之间。因此修正的Penman-Monteith公式是森林地区水量平衡计算的有效工具。

Study on the evapotranspiration simul ation of sub-alpine forest area in Gongga Mountain

The Penman-monteith formula is applied to simulate the dynamic of evapotranspiration for naked land,Abies fabri forest and shrub-grass areas.The simulated results show that net radiation,air temperature and vegetation types are the predominant factors to control the dynamic of evapotranspiration.The evapotranspiration process modeled for naked land is similar to the observed evaporation of water surface.The higher values of evapotranspiration appear in April and September respectively owing to more sunshine and lower air humidity,while the lower values appear in July and August for great deal of rainy days.The simulated values of evapotranspiration of forest and shrubgrass areas are higher in growth period,or lower in non-growth period than that of naked land surface.The difference between these two kinds of land surface varies by ±25%.The simalated results show that the modified Penman-Monteith formula can be used satisfactorily in the hydrological cycle analysis for mountain regions with forest coverage.