基于闪烁仪观测低丘山地人工混交林通量印痕与源区分布

参考Meijninger提出的适用于大孔径闪烁仪(LAS)法的印痕模型,利用位于河南省济源市的华北低丘山地30年生栓皮栎-侧柏-刺槐人工林生态系统的主要生长季2009年5～9月通量等观测数据,计算、分析了该森林生态系统的通量印痕及源区分布.结果表明:①以90%通量贡献区面积为测算对象,不同风向条件下,在大气不稳定时,东南风向时源区面积最小,为1.1547 km2,西南风下最大,为1.5237 km2;在大气层结稳定时,西北风向时源区最小,为1.7271 km2,西南风向时最大,为3.5289 km2.并且在大气不稳定时的源区面积均小于稳定条件下的面积.其中,大气层结稳定时面积最小的西北风向时的源区面积比不稳定时面积最大的西南风向时的源区面积还要大11.8%.②以90%通量贡献区面积为测算对象,晴天条件下,由于湍流交换的逐渐加强,上午源区面积由8:00的1.1483 km2减小到11:00的0.4518 km2.中午之后,湍流交换逐渐减弱,大气趋向稳定层结,源区面积由14:00的0.4779 km2增加到17:00的0.7137 km2.通量源区面积的日变化趋势与大气稳定状况和湍流交换变化趋势大致一致.③以80%通量贡献区面积为测算对象,受大气状况、风向及下垫面性状的影响,各月通量源区各不相同.2009年5～9月期间,各月源区面积分别为1.834、1.680、2.043、1.671、1.380 km2.

Distribution of Flux Source Area and Footprint for the Scintillation Method over a Mixed Plantation in the Hilly Zone of the North China

Based on the Meijninger(2002) model and the continuous flux measurement over a 31-year aged mixed plantation in the hilly zone of the North China from May to September in 2009，the source area and footprint of the plantation flux for large aperture scintillometer(LAS) method were calculated in the main growing season . The results showed that:①The range of source area under NW that is the smallest in stable stratification conditions is 11.8% bigger then the source area under SW that is the biggest in unstable stratification conditions. ②The range of source area is 1.1483 km² at 8:00 when stratification conditions become unstable exactly; The range of source area source area is 0.4518 km² at 11:00 as is the smallest in ae day. The range of source area becomes 0.7137 km² from 0.4779 km², when stratification conditions become stable from unstable. The changing trend of source area is consistent with radiation and temperature.③The range of source area is 1.834 km²,1.680 km²,2.043 km²,1.671km²,1.380 km², in May, June, July, August, September respectirely.