若尔盖高寒湿地夏季近地面水平热平流对地表能量闭合度的影响研究

近地面能量不闭合问题一直以来都是陆面过程研究的一个重要的科学问题,且在非均匀湿地下垫面的近地面尤为突出.利用中国科学院若尔盖高原湿地生态系统研究站花湖观测场的地面风场和温度场数据,计算了由湿地下垫面热力非均匀性引起的水平热平流,并分析了考虑水平热平流后地表能量平衡的变化.结果表明:2017年夏季若尔盖湿地近地面水平热平...

Research on the Influence of Horizontal Thermal Advection on Surface Energy Balance in Zoige Alpine Wetland

The near-surface energy budget closure has always been a scientific hot topic in the land-surface processes research,especially over the underlying surface of heterogeneous wetlands.In this investigation,the horizontal thermal advection caused by thermal inhomogeneity of the underlying surface over the wetland is calculated based on the data of the Flower-lake observation field in the Zoige alpine wetland.With considering the horizontal thermal advection,its contribution to the near-surface energy closure is analyzed.The results show that the mean horizontal thermal advection of the Zoige wetland is 22.9 W·m^-2,and the maximum value can reach58.7 W·m^-2 in the daytime of summer 2017.After introducing the horizontal thermal advection and soil heat storage into the near-surface energy balance equation,the near-surface energy closure ratio increased from 41.8% to 67.9% in summer.The contribution of horizontal thermal advection was 5.8%,that of soil thermal storage was 20.1%,and that of plant photosynthetic thermal storage was 1.0%.The diurnal variation of the near-surface horizontal thermal advective is equivalent to the sensible heat flux in Zoige wetland,and the maximum diurnal variation is about one third of the thermal storage of the wetland soil.