# Evaluation of the Urban Weather Generator on the City of Toulouse (France)
## 2 Materials and Methods
### UWG: Urban Weather Generator Model
#### 2.2.2 Model Input and Output Data  
This part details which data are required to run UWG and how they have been generated in this study. Two families of parameters are required: rural data and urban information. UWG requires two input files: an epw. file in Appendix A and an uwg. file. The first file contains rural station data. The second file contains information on the urban geographic position for which air temperatures will be simulated with UWG. **Rural data**:  
We selected three potential reference rural stations: Meteopole in LCZ 5 (i.e., Open midsize), Mondouzil in LCZ 9 (i.e., Sparsely built), and Centre equestre in LCZ 16 (i.e., Bare soil or sand). Mondouzil and Centre equestre belong to rural station criteria as defined in [29]. Despite a more urbanized environment, Meteopole station is also selected as a rural reference as it is located in a rather green area (La Ramee green area park). It is a reference measurement station from Meteo-France and the only rural station over Toulouse where the radiative fluxes and the soil temperatures are acquired. For the other rural stations, the radiative fluxes and soil temperatures used are taken from the Meteopole station. These stations provided us with weather data (air temperature, wind speed, atmospheric pressure, humidity, etc.) _Data acquired from Meteopole station:_  
As for meteorological inputs, UWG requires:  
1. Four radiative fluxes: horizontal infrared radiation, horizontal global radiation, horizontal solar diffuse, and normal solar direct radiation;
2. Monthly averages of soil temperatures for three different depths. We derived these data from Meteo-France measurements at the Meteopole station (see Section 2.1.3) where radiative fluxes and soil temperatures are available. Table 3 presents the correspondence between the required UWG variables and the source data along with the name of the associated variable in the.epw configuration file required for initializing UWG. Concerning soil temperature, we choose 1 cm, 80 cm, and 220 cm depths where an average soil temperature has been computed for each month. Since we only have one piece of information on radiation issued from Meteopole station given by Meteo-France, we have decided to use the same radiation data for all rural reference stations. **Urban information**:  
Parameters describing the **surface** state of the city are crucial to run UWG. They can be divided into 3 groups, as described below:  
1. _Urban Characteristics_. This group concerns local characteristics related to artificialisation and more precisely the density of buildings, their height, and the vertical-to-horizontal ratio. In practice we rely on the BD TOPO 2021, from the French National \begin{table}
\begin{tabular}{l l l} \hline \hline
**Variable (\(\mathbf{W/m^{2}}\))Source** & **CNRM File (Source Data)** & **.epw File (UWG** \\
**Simulations)** & \\ \hline Horizontal Infrared Radiation & Downward Longwave & Horizontal Infrared Radiation \\ Intensity & \\ \hline Horizontal Radiation & Downward Shortwave & \\ Radiation (\(SWD\)) & Global Horizontal Radiation \\ \hline Horizontal Solar Diffuse & Downward Diffuse Shortwave & \\ Radiation & Radiation (\(SW\_DIFFUS\)) & Diffuse Horizontal Radiation \\ \hline Normal Solar Direct Radiation & Non-existent in the initial file, calculated with: & \\ \(SWD-SW\_DIFFUS\) & Direct Normal Radiation \\ \(\overline{\text{cos}(solar zenith angle)}\) & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: **Radiative fluxes** according to the CNRM source file and their correspondences in the.epw initialization (file for UWG simulations). Institute of Geographic and Forest Information [47], to extract these values. In detail, a Digital Surface Model (DSM) at 1 m spatial resolution has been computed from the vector data [47]. From it, the three previously mentioned geomorphological indicators have been computed. 2. _Vegetation parameters._ They represent information related to the vegetation, especially the tree and grass cover ratio.