Wind Shear

[Rae]

Hello.

I am a very beginner of WENG.

So I would like to ask some questions.

I know that WENG could calculate Wind Shear.

As far as I know,

But In my opinion, WENG could not calculate horizontal wind shear

When I calculate wind shear, the wind shear of just one height was showed.

(I mean I have a 40m, 50m, 60m, 70m mean wind speed. I would like to calculate the wind shear corresponding of the whole of each height, I think I have to input just one height to calculate wind shear. right? That meaning is We could know wind shear only one height. right? If not, I would like to know about it..)

Thank you.

P.S If you have question, please let me know.

[Morten]

WEng estimates the shear exponent from calculations at just one height. The flow is modelled in Fourier space, so a convenient way to calculate fields of velocity gradients is to multiplying wave numbers with wave vectors and then do inverse FFT. You can get the full matrix of velocity gradients - from dU/dx to dW/dz - in this way.

Having found the velocity and velocity gradient fields, WEng is able to extract velocities and vertical gradients at any site and estimate shear parameters by the formula

alpha=dU/dz*z/U

Here, the gradient and velocity corresponds to the selected height. This alpha exponent is a good fit near the selected height. However, if the real profile is not an exact power law you will get slightly different alpha values if you select other calculation heights.