EXAMPLES
FILL UP MISSING WIND DATA
 order 

Example for the
fill-up of missing wind data

 

Missing wind speed values within a wind speed profile are filled up with the following methods:

  • Logarithmic wind speed profile fit (3-parameter fit with friction velocity, roughness length, and displacement height "logarithmic fill-up" in the following).
  • Linear regression versus the height levels ("linear fill-up" in the following).
  • Linear interpolation between the height levels.

Missing wind directions within a wind direction profile are filled up with the following methods:

  • Special regression versus the height levels ("cyclic linear fill-up" in the following). This regression specifically applies for cyclic quantities like the wind direction and reflects the rotation of the wind direction with height correctly.
  • Special interpolation between the height levels. This interpolation specifically applies for cyclic quantities like the wind direction.

If after the fill-up values still are missing, for example due to a measuring system malfunction, then the still missing values can be filled up with the extrapolated values resulting from an MSSCP.

In the following example (time series with 31 height levels from 50 m to 200 m), missing wind speeds and missing wind directions have been filled up.

Fig.1 shows the original wind speed profile at a certain time step, and the respectively logarithmic filled up wind speeds. Fig.2 shows the original wind direction profile at the same time step, and the respectively cyclic linear filled up wind directions.

Fig.3 shows the original wind speed profile at a certain time step, and the respectively linear filled up wind speeds. Here, the logarithmic wind profile fit failed and the linear regression was used instead. Fig.4 shows the original wind direction profile at the same time step, and the respectively cyclic linear filled up wind directions.

Fig.5 shows an excerpt of the wind speed time series after the fill-up of the wind profiles. Fig.6 shows the same excerpt after the wind speeds have been filled up additionally with MSSCP.

Fig.7 shows the availability of the wind speed data over the entire time series before the fill-up (original), after the fill-up of the wind profiles (LPF filled), and after the fill-up with MSSCP (MSSCP filled). Fig.8 shows the availability of the wind direction data over the entire time series before the fill-up (original), after the fill-up of the wind profiles (LPF filled), and after the fill-up with MSSCP (MSSCP filled).

Fig.9 shows the average of the wind speed over the entire time series before the fill-up (original), after the fill-up of the wind profiles (LPF filled), and after the fill-up with MSSCP (MSSCP filled). Fig.10 shows the average of the wind direction over the entire time series before the fill-up (original), after the fill-up of the wind profiles (LPF filled), and after the fill-up with MSSCP (MSSCP filled).

 

Fig.1:
Original and logarithmic filled up wind speed profile
Fig.2:
Original and cyclic linear filled up wind direction profile
Fig.3:
Original and linear filled up wind speed profile
Fig.4:
Original and cyclic linear filled up wind direction profile
Fig.5:
Wind speed time series after the fill-up of the wind profiles
Fig.6:
Wind speed time series after the fill-up with MSSCP
Fig.7:
Availability of the wind speed data at the different heights
Fig.8:
Availability of the wind direction data at the different heights
Fig.9:
Mean wind speed at the different heights
Fig.10:
Mean wind direction at the different heights
© WIND DATA SUiTE - Dr. Helmut Frey      Last modified: 2018-12-02