Estimating the components of the sensible heat budget of a tall forest canopy in complex terrain
Estimating the components of the sensible heat budget of a tall forest canopy in complex terrain
复制标题
估计复杂地形中高大森林冠层的显热收支的组成部分
DOI：
10.1007/s10546-006-9136-7
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发表时间：
2007
影响因子：
4.3
通讯作者：
C. Bernhofer
中科院分区：
文献类型：
--
作者：
Uta Moderow;C. Feigenwinter;C. Bernhofer
超声波风测量，声波温度和空气温度数据在两个高度的平流实验MORE II被用来建立一个完整的预算的感热，包括垂直平流，水平平流和水平湍流通量散度。MORE II在德国Tharandt的长期Carbo-Europe IP站点举行。在2003年的增长期间，建立了三个额外的塔，以测量所有相关参数，估计平流通量，主要是二氧化碳。此外，结合其它平流实验，提出了水平湍流通量散度的计算方法，并讨论了水平湍流通量散度与大气稳定度和摩擦速度的关系。为了获得一个完整的预算，不同的标度高度的水平平流和水平湍流通量散度进行了测试。结果表明，忽略平流通量可能导致不正确的结果。如果考虑平流通量，则仅基于垂直湍流通量和储存变化的感热收支减少约30%。水平湍流通量发散的额外考虑又会使该总和增加5-10%（即，垂直湍流通量加上储存变化加上水平和垂直平流的总和）。与可用能量相比，水平平流在夜间是重要的，而水平湍流通量散度是相当微不足道的。显然，平流通量通常改善夜间能量收支关闭，并可能改变生态系统呼吸通量显着。
Ultrasonic wind measurements, sonic temperature and air temperature data at two heights in the advection experiment MORE II were used to establish a complete budget of sensible heat including vertical advection, horizontal advection and horizontal turbulent flux divergence. MORE II took place at the long-term Carbo-Europe IP site in Tharandt, Germany. During the growing period of 2003 three additional towers were established to measure all relevant parameters for an estimation of advective fluxes, primarily of CO2. Additionally, in relation to other advection experiments, a calculation of the horizontal turbulent flux divergence is proposed and the relation of this flux to atmospheric stability and friction velocity is discussed. In order to obtain a complete budget, different scaling heights for horizontal advection and horizontal turbulent flux divergence are tested. It is shown that neglecting advective fluxes may lead to incorrect results. If advective fluxes are taken into account, the sensible heat budget based upon vertical turbulent flux and storage change only, is reduced by approximately 30%. Additional consideration of horizontal turbulent flux divergence would in turn add 5–10% to this sum (i.e., the sum of vertical turbulent flux plus storage change plus horizontal and vertical advection). In comparison with available energy horizontal advection is important at night whilst horizontal turbulent flux divergence is rather insignificant. Obviously, advective fluxes typically improve poor nighttime energy budget closure and might change ecosystem respiration fluxes considerably.