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02-Jul-2022   
Path: RAMI-IV : EXPERIMENTS : ACTUAL CANOPIES : SHORT ROTATION FOREST : Vertical profile of total transmission through canopy
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Vertical profile of total transmission through canopy: ftran_tot_vprof

This measurement comprises two quantities, namely, the fraction of radiation traveling either upward or downward at 11 precisely defined height levels within the canopy. For each height level z, the up- or downward travelling radiation streams (F_up and F_down, respectively) are normalised by the incident radiation at the top of canopy, i.e., T_down@z = F_down@z ⁄ F_down@Zmax and T_up@z = F_up@z ⁄ F_down@Zmax - where Zmax defines the top-of-canopy level. The highest of the 11 height levels occurs at Zmax (such that T_down_Zmax = 1) and the lowest height level nominally occurs at 0.0 m (or just above the underlying background surface). The actual value of Zmax is available on the experimental description pages. The interval between the 11 height levels is obtained from Zmax ⁄ 10. Note that this measurements deals with total (direct and diffuse) transmission profiles. Also note, that since fluxes are defined with respect to some reference plane, all of the above quantities have to pass through virtual reference surfaces at height levels z and Zmax. Such a (virtual) reference surface covers the entire spatial extent of a given scene and is oriented parallel to the underlying background surface.

Within RAMI-IV this measurement applies to all canopy scenes.

    Formatting of measurement-file content:

    Header line content # rows # columns in file heigth level interval
    Header line format integer integer real
    Content height level [m] upward relative flux [-] downward relative flux [-]
    Format real real real

    A real is defined as having 6 digits after the decimal point, e.g., 1.000000.

    Order of output in file should be such that the first row relates to the fluxes at the top-of-canopy height level and the last row relates ot the fluxes at the bottom-of-canopy heigth level.

    Example output:

    11 3 0.411330
    4.113300   0.141735   1.000000
    3.705664   0.141582   0.999122   
    3.293911   0.141189   0.995436   
    2.882158   0.137624   0.966222   
    2.470405   0.127586   0.883906   
    2.058651   0.120395   0.792309  
    1.646898   0.117929   0.720247
    1.235145   0.121600   0.674629
    0.823392   0.129983   0.645828
    0.411638   0.136868   0.637807
    0.000003   0.137448   0.637460
    

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