Parameterization of land surface evaporation by means of location dependent potential evaporation and surface temperature range
Parameterization of land surface evaporation by means of location dependent potential evaporation and surface temperature range
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发表时间：
2007
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通讯作者：
M. Mementi;B. Choudhury
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作者：
M. Mementi;B. Choudhury
提出了一种新的参数化方法，通过定义一个位置相关的潜在蒸发量和表面温度范围，以考虑实际蒸发量的空间变异性，由于对流和空气动力学粗糙度。这是通过使用组合式方程来完成的，该方程根据对热和蒸汽流的内部和外部阻力来参数化实际蒸发。这个方程首先被重新排列，以明确地得到空气与表面的温差。其次，通过取蒸汽流的内阻力为零和（o°）的极限，导出了该方程的渐近形式。对于给定的蒸发量和空气动力学粗糙度值，具有最大和最小温差，定义了无量纲比，其在0（无蒸发蒸腾）和1（实际=潜在蒸发）之间变化，作为测量的空气与表面温差的函数。建议用大气边界层顶的空气位温代替近地面空气温度。最后给出了应用实例。
A new parameterization is proposed by defining a locationdependent potential evaporation and surface temperature range to account for spatial variability of actual evaporation due to albedo and aerodynamic roughness. This was done by using a combination type equation which parameterizes actual evaporation in terms of internal and external resistances to heat and vapour flow. This equation was first re-arranged to get the air to surface temperature difference explicitly. Next, the asymptotic forms of this equation were derived by taking the limits for the internal resistance to vapour flow being zero and (o°). Having the maximum and minimum temperature differential for given values of albedo and aerodynamic roughness, a non-dimensional ratio was defined which varies between 0 (no évapotranspiration) and 1 (actual = potential evaporation) as a function of measured air to surface temperature difference. It is proposed to use air potential temperature at the top of the Atmospheric Boundary Layer instead of near surface air temperature. An example of application is presented.