Arya Posted June 3 Share Posted June 3 Hello Team, I was not able to find anywhere which method is used to calculate the weibull parameters A and k. Can anyone confirm the method of weibull estimation used and whether there are any special approaches taken by WASP in the estimation? Link to comment
Rogier Posted June 4 Share Posted June 4 It is probably easiest to check this code for the calculation: https://docs.wasp.dk/windkit/_modules/windkit/weibull.html#_fit_wasp_m1_m3_fgtm Link to comment
Arya Posted June 8 Author Share Posted June 8 Thank you so much. I was specifically looking for the calculation of weib_A_combined and weib_k_combined values which is obtained from downloading the wind data from Microscale API https://wps.neweuropeanwindatlas.eu/api/microscale-atlas/v1/get-data-bbox. Do they use https://docs.wasp.dk/windkit/_modules/windkit/weibull.html#_fit_wasp_m1_m3_fgtm as well for the calculation of weib_A_combined and weib_k_combined ? Link to comment
Rogier Posted June 17 Share Posted June 17 Yes that calculation is similar except you don't need the fgtm (frequency greater than mean) variable, because the inputs for NEWA microscale are sectorwise A and k's, the fgtm is only required when you have a wind speed histogram as input. The first and third moments are calculated from the wind direction frequency weighted first and third moments and then you can use `_fit_wasp_m1_m3` to find the combined A and k from those. Link to comment
Arya Posted June 24 Author Share Posted June 24 Thanks that was helpful. How is sectorwise A and k's, first and third moments calculated by NEWA Link to comment
Rogier Posted June 24 Share Posted June 24 You can see that in this code: https://docs.wasp.dk/windkit/_modules/windkit/weibull_wind_climate.html#weibull_combined It is getting the sector weighted first and third moments and does the weibull fitting with the method `_fit_k_sumlogm` Link to comment
Arya Posted July 10 Author Share Posted July 10 Thank you so much for the update. Your response was very helful to us. My understanding is weibull_combined function in https://docs.wasp.dk/windkit/_modules/windkit/weibull_wind_climate.html#weibull_combined gives us the sector combined shape and scale values along with that it calculates the 1st and 3rd moments. These are calculated by taking the sectowise A and k and sectowise wind frequency. I have few questions. I hope you would be kind enough to answer them. 1. What is in resource file? Is sectorwise A, k and wdfreq already present in resource file ? From where do we get the resource file ? 2. How is sectorwise A and k and sectorwise wind frequency calculated ? Is it provided by meterological stations directly? Do they have any software to calculate this? I tried to understand how this is calculated by referring to "European wind atlas" but was not able to get a clear picture of it. Thanks, Arya Link to comment
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