wind data

[dachiller]

Dear WAsP Team and dear WAsP-Users,

I am planning on writing my Bachelor thesis on a project with WAsP and I want to evaluate the wind potential analysis. I am searching for Winddata to validate my simulating results. Do you know, if possible, free wind data? I found some myself but it would be great to have some more, especially from higher hub heights.

Also I was wondering why my WAsP output wouldn't give me the Weibull-Parameters for the 'all sector'? It is only presented in the diagramm, but I can't automatically export them. Is this intended and is there a way to fix this?

Thanks for your help!

[Duncan]

I don't know about the availability of free data. Perhaps someone else can help.


WAsP doesn't display the all-sector Weibull because that is a depreciated result. For all-sector numbers, we use the 'emergent' distribution which is different combination of sector-wise results which may legitimately result in a distribution which is not Weibull-shaped.

We still show the A and k parameters of the combined Weibull distribution in the graph, but these numbers are greyed and are just for reference against older data. We draw both the emergent and the combined distributions in the graph, and they are usually a good match so it's not clear that there are two lines.

[dachiller]

Well I was planing to use the Weibull-parameters as an indicator for the wind speed distribution, or is there a better way to do this?
I guess I have to manually write them down then.
I got some more questions though, I hope it's ok if I use this thread!
I was wondering if the 'gwc' is just transfered (aka it is the same for measurement site and investigation site) and only the local effects at the investigation site take effect on it?
If so, do I need a map, which contains both sites or would it be enough to have a map for each site with blank space between them?
I am asking because my map got over 1,000,000 lines already (compare http://www.wasp.dk/Support/FAQ/DigitalMaps.aspx), it is still working thou! This might change if I add 2m contour lines near the sites and also add roughness data. Also the progressing in the map editor is really time intensive this way.
Also I am not quite sure, if I need to do a dRIX analysis myself or is it implemented into WAsP already?
Also I am going to use the global mapper feature of creating roughness areas, but they offer them for winter and summer seperatly. Which one should I use or can I combine them? (I guess this one is more a question for the global mapper forum though, but maybe someone here knows this issue)

[Duncan]

Hi,

I think that the general recommendation is that you should calculate and use your GWC (wind atlas) in the same project. But in principle they are portable between projects if the general conditions are sufficiently similar. So you can use part of the map in one project where you calculate the GWC, then save it out to disk and use it in another project where you use a different part of the map.

The WAsP program can now handle extremely large maps, but remember that there is unlikely to be any modelling benefit from including high-density information far away from the sites of interest.

Delta-RIX corrections are not performed automatically by the program.

What data source is offering different winter and summer roughness? These can be very good, but you need to split the climate data into equivalent seasons, perform two calculations in WAsP and then make a weighted average of results.

Have you considered attending the WAsP course? It sounds like you have a lot of questions which would be answered properly there.

[dachiller]

Thanks for your answers, once again. You really are a great help!
I cannot attend a course thou, because I need to finish my project really soon. But I think I got the most important information now.
I think globalmapper just applies different roughness length values for the different land uses in dependency of the season and it is kind of work intensive to do weighted averages with 50+ calculations. But I'll address this problem in the near future!