Wind Climate Objects
As described in the WindKit Introduction, WindKit relies on specifically structured xarray datasets in addition to classes to store data in memory. Below you will find out about the different types of objects that are present in WindKit.
Time Series Wind Climate
time_series_wind_climate (twc) contains a time series of
wind speed and
wind direction. It is a the most basic wind climate from which all others can be derived. It also is the largest of the wind climates retaining all of the original information.
In addition to the Core coordinates, twc objects also contain the dimension
time, which identifies the time of the given wind data.
Binned Wind Climate
binned_wind_climate (bwc) contains a histogram representation of the wind, for different wind direction sectors. Historically these have been used for encoding observational data, and in WAsP Observed Wind Climate is used for this type of data. However there is no reason that they couldn’t be used for other wind data as well. In WAsP, these are stored in “.tab” and “.owc” files, which can be read using WindKit.
In addition to the Core coordinates, bwc objects also contain the dimension
wsbin, which identifies the wind speed bins of the histogram. Wind speed bins are characterized by their upper boundary, e.g. a wind speed bin from 0-1 would be identified with a wind speed value of 1.
In addition to reading bwc’s from files, you can create them from weibull distributions and time-series data.
Generalized Wind Climate
A Generalized Wind Climate is a key part of the WAsP Methodology. The
generalized_wind_climate (gwc) contains the wind in a virtual world, where there is no terrain and there are homogeneous roughness values, i.e. no roughness changes. Generalized wind climates are represented as Weibull distributions (scale [A]; shape [k]) and sector-wise frequency values. Because the gwc exists in a virtual world, it contains several additional dimensions compared to the other wind climate files.
gen_height is the height above the constant terrain in the generalized atmosphere, and
gen_roughness is the homogeneous roughness length. In WAsP, you were limited to exactly five of each of these parameters, however in WindKit you can use as many or as few as you wish.
WindKit provides the ability to create gwc objects from “.lib” and “.gwc” files. This is used
Weibull Wind Climate
weibull_wind_climate (wwc) is related to the Binned Wind Climate, but instead of a histogram, it is represented solely as the weibull parameters for the different sectors. In WAsP, this was often stored as “.rsf” files, which can be read from WindKit. These are the objects that most often store the results of a WAsP simulation.