Maximun calculation ratio for a metheorological station (2006-01-06)

[Old Forum Archivist]

Hi

i`d like to know if there`s some criteria for to know haow far can i go with grids calculation for one metheorological station? i mean, how many kilometers away can i go in calculation for the same type of landscape?



Thanks
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If I understand well, you would like to know the resources

of a site, which is let's say 100 km away from a met. stat.

Your question is: the data collected by a met. stat. is

applicable this far as well?

I would like to know this too. The only thing I've found:

http://www.wasp.dk/Support/FAQ/Maps/SRTM2MAP.html

In this document at Step 5 it says: 'For a met. station site

one might choose to make a 20 by 20 km2 map with 50-m

contours, a 10 by 10 km2 map with 10-m contours and

a 2 by 2 km2 map with 5-m contours - all centered around

the met. station.'

I'm not sure, but out of this I drew a conclusion that

the range of a met. stat. is no more than 10 kilometers

(20 kms in diameter).--------

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The criteria itself is simple: The met. station and the turbine site should be subject to the same overall weather regime, i.e. they should have the same regional wind climate (same wind atlas). But how to determine the distance is not so easy...



The distance is determined by the change in weather regime with distance; this again depends on the type of dominating weather systems (e.g. Westerlies, Trade winds, etc.) and how these are influenced by the large-scale terrain (mesoscale effects). For simple terrain and cyclonic-type weather regimes (e.g. many places in NW Europe) the distance could be of the order of 50 km, but in places with more complex topography/climatology it might be only 5 km or even less. So, the distance can only be estimated from analyses of the actual place and situation.



The WAsP Team

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This conclusion is not right! The size of the map is determined by the model employed: the WAsP models take the terrain within a distance of about 10 km in to account. So, terrain features further away would influence the model results very little, if at all.



Also, the two sites need not be in the same map: You could have one 20x20 km map at the met. station and another 20x20 km map at the turbine site and the distance between the two sites could be anywhere between 0 and, say, 50 km, depending on the topographical/climatological situation. As long as the two sites have the same regional wind climate (wind atlas) then this would be alright.



The WAsP Team

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