## 2 Data and Methodology
### Adaptation of Calibrated Wind Speed Series to ROSEO-BIWT's Peculiarities  
#### 2.4.1 Correction of Wind Speed Series  
Due to architectonic and legal restrictions, the anemometer could not be located at the same spot as the hypothetical turbine. Instead of being on the edge between the roof and the center of the facade, where the concentrating effect of the building is more potent, it was installed over the roof on one side of the building, as shown in Figure 7. This caused the measured wind speed to be lower than what empirical observations suggested a hypothetical turbine could receive.  
This was compensated by multiplying the wind speed series by a range of augmenting factors, which are the ratio between the mean wind speeds at the anemometer's and the turbine's locations. These were deduced from the findings of previous research done on the difference of the wind speed on the area around the roof relative to the free wind speed [24].  
\begin{table}
\begin{tabular}{l l c c} \hline \hline
**Name** & **Grid Points** & **Splitting Criteria** & **Splits** \\ \hline Simple & Closest 9 & None & 1 \\ Directional & Closest one & ERA5 wind direction & 8 \\ Seasonal & Closest one & Season & 4 \\ Combined & Closest one & ERA5 wind direction \& Season & \(8\times 4=32\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Summary of the distinctive properties of the QM (Quantile Mapping) calibrations performed.  
According to this paper, the installation site (that is, the spot just above the edge between the roof and the facade facing the wind) has wind speeds that are between 0.33 and 0.9 times the free wind speed. Our hypothesis is that this difference is constant for the entire wind speed range for a given building and facade. So, by knowing the mean wind speed value between the wind at the anemometer and the free wind, we can also calculate the factors. Since the free wind is the wind that occurs at such a height where it is no longer slowed down by the roughness of the terrain, the 100-m wind data from ERA5 was used as free wind.  
They were calculated as follows: first, the data pertaining to the times when the wind was facing the selected facade (using the 120\({}^{\circ}\) range explained in Section 2.2.2) was separated from the rest. Then, within this subset of data, the averages of the measured and ERA5's 100 m wind speeds were calculated, and the former was divided by the latter. We will call this factor \(f_{a}\), which is equal to 0.26.  
Another factor, called \(f_{b}\), represents the difference between the mean wind speeds at the edge and at 100-m height and can be extracted from the CFD simulation results of [PERSON] et al. (2014). In order to take into account different scenarios regarding the increase of the wind speed at the edge, three different values were used. We will call them \(f_{b_{1}}\), \(f_{b_{2}}\), and \(f_{b_{3}}\), and their values are 0.33, 0.6, and 0.9, respectively.  
Lastly, by dividing \(f_{b}\) by \(f_{a}\), we got what we will call \(f_{c}\), which is the difference between the edge and the anemometer's spot, that is, the correcting factors for the measured and calibrated wind speed series. Having different values for \(f_{b}\) means that we got different values for \(f_{c}\): \(f_{c_{1}}\) is equal to 1.28, \(f_{c_{2}}\) to 2.34, and \(f_{c_{3}}\) to 3.50. The equations below summarize the calculations. \(AnemWS\) is the mean wind speed value of the measured wind speed inside the absorption range, \(FreeWS\) is the mean wind speed of the ERA5's 100-m data pertaining to the same data points \(AnemWS\), and \(EdgeWS\) is the mean speed of the wind that, according to these calculations, the turbine would receive.  
\[f_{a}=\frac{AnemWS}{FreeWS}=0.26,\]  
\[f_{b}=\frac{EdgeWS}{FreeWS},\]  
\[f_{b_{1}}=0.33,\]  
\[f_{b_{2}}=0.6,\]  
\[f_{b_{3}}=0.9,\]  
\[f_{c}=\frac{f_{b}}{f_{a}}=\frac{EdgeWS\times FreeWS}{FreeWS\times AnemWS}= \frac{EdgeWS}{AnemWS},\]  
\[f_{c_{1}}=1.28,\]  
\[f_{c_{2}}=2.34,\]  
\[f_{c_{3}}=3.50.\]