Dear Benjamin,

The easiest way is to use the following method to calculate H obtained from METRIC manual by Alen et al., 

The only thing you need is some climate data such as Temperature, Wind speed, pressure.

Use the following 

Sensible heat flux is the rate of heat loss to the air by convection and conduction, due to a

temperature difference. It is computed using the following one-dimensional, aerodynamic,

temperature gradient based equation for heat transport

                                                                            H = (r × cp × dT) / rah

where: r is air density (kg/m3), cp is air specific heat (1004 J/kg/K), dT (K) is the

temperature difference (T1 – T2) between two heights (z1 and z2), and rah is the

aerodynamic resistance to heat transport (s/m)

ρ =  1000 P/(1.01(Ts- dT) R)

where: r is air density (kg/m), P is mean atmospheric pressure, R is the specific gas

constant (287 [J kg/K]), Ts is the surface temperature (K) for a pixel, and dT is the near surface air temperature difference defined above.

rah = (ln(z2/z1)/(u*Xk)

where: z1 and z2 are heights in meters above the zero plane displacement (d) of the

vegetation, u* is the friction velocity (m/s) which quantifies the turbulent velocity fluctuations

in the air, and k is von Karman’s constant (0.41). The friction velocity (u*) is computed

during the first iteration using the logarithmic wind law for neutral atmospheric conditions

u* = kux/ln(zx/zom)

where: k is von Karman’s constant, ux is the wind speed (m/s) at height zx, and zom is the

momentum roughness length (m). zom is a measure of the form drag and skin friction for the

layer of air that interacts with the surface.

zom = 0.12h

where: h is the vegetation height (m).

Thanks Awad, I am looking at this. I will get back soon.

Hi Awad,

I have looked through the equations and have computed some of the parameters. However where do I use equation 2?

ρ = 1000 P/(1.01(Ts- dT) R)

And I also want to know if the computations are just straight forward as you have described them or I need to do some iterations?

Thanks in advance