Land surface models use parameters to describe the surface. For example to model the latent heat flux using the Penman Monteith equation the following parameters are needed.
From the short-wave radiation (K), within the qstar radB the albedo (alpha) is calculated:
α = K↑/K↓
using the incoming (↓) and outgoing (↑) shortwave radiation (K) fluxes.
- Land cover type
- Time of year
- Time of day
- Location
- Reference
If the displacement height is known, or is negligible, the logarithmic law equation can be rearranged with observed z0 and mean wind speed to allow z0 to be determined. As this may vary we normally take median of a minimum of 20 results for a wind direction sector. If you have a period with a lot of neutral conditions you may be able to get a lot of samples rapidly.
A rule of thumb for calculating d is to assume it is ~0.75 h where h is the height of the canopy. As the heights may vary with direction you can determine how much this may vary. What are expected to be consistent sectors?
The wind profile can also be used to determine z0 and d if there are more than 2 levels in the profile. This requires fitting a straight line (linear regression) through the data to determine the intercept, which provides the z_0+d value. See equations 1-2 in grimmond1998aerodynamic.
For References see list