Wind speed comparison at two sites - a question

[PGE]

Hi all, 

I'd like to ask your opinion on the issue below. Perhaps you would be able to point to the approximate solution.

We have 2 sites - the first one on the sea (ST1), the second one (situated about 10km away from the first one) on the shore - the shore is covered with a coniferous forest (ST2).

At ST2 there is a sodar, which is able to measure wind speed at various levels above ground. The idea is to find an approximation of wind speed at ST1 using the sodar measurements at ST2. How can this be done? Eg. can we find an approximate height above the ground at ST2 where the wind speed would be comparable to the wind speed at ST1 (the sensor here is situateed 4m above sea level)?