# Odor Impact Assessment via Dispersion Model: Comparison of Different Input Meteorological Datasets
## 2 Materials and Methods
### Calmet
#### 2.2.2 CALMET Parameters  
To run CALMET simulations, US-EPA-recommended parameter values [44] or CALMET default values were generally adopted, if available. However, the definition of model parameters for TERRAD, BIAS, R1, R2, RMAX1, and RMAX2 is mandatory (at least for CALPUFF \"OBS\" mode), but no default values or clear suggestions are provided in the Model User's Guide. The adopted values for these parameters are reported in Table 2. The rationale behind the selection of these numerical values will be briefly discussed, with the purpose of identifying the optimal configuration for CALMET settings. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Site** & **Station Acronym** & **Type** & **Coordinates** & **Elevation ASL [m]** &
\begin{tabular}{c} **Distance Met** \\ **Station–Domain Center [km]** \\ \end{tabular} \\ \hline Italy & LDR & Surface & 45.32\({}^{\circ}\) N, 9.27\({}^{\circ}\) E & 88 & 2 \\ Italy & LIML & Upper & 45.43\({}^{\circ}\) N, 9.28\({}^{\circ}\) E & 101 & 13 \\ Cuba & AGP & Surface & 22.37\({}^{\circ}\) N, 80.83\({}^{\circ}\) W & 24 & 2 \\ Cuba & KW & Upper & 24.55\({}^{\circ}\) N, 81.75\({}^{\circ}\) W & 6 & 240 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Meteorological stations selected for dispersion simulation. TERRAD identifies the influence radius of terrain features and is required to run CALMET simulations for all the investigated input meteorological settings [38]. A sensitivity analysis with different TERRAD parameters was conducted to find the optimal value to minimize the Root Mean Square Error (RMSE) of the wind speed by comparing the \"NO-OBS\" CALMET output values with the observed measurements following [45]. Due to the flat orography of both domains (i.e., Italy and Cuba), RMSE values resulting from simulations with different TERRAD parameters were very similar. Through an optimum analysis, TERRAD was set to 3 km and 0.1 km for the Italian and Cuban domains, respectively. The BIAS parameter, required only in the \"OBS\" and \"HYBRID\" mode, determines the relative weight associated with the surface measurements versus upper air data in the computation of the initial guess wind field [38]. By setting BIAS to \(-1\), upper-air observations are not taken into account in the interpolations for this layer. Conversely, by setting BIAS to +1, surface observations are not considered in the interpolations for this layer. One hundred percent of the weight (BIAS = \(-1\)) is attributed to surface meteorological data in the first vertical layer. These data have 0% weight in the last two layers (BIAS = 1). As recommended by [PERSON] [37] and [PERSON] [39], the same weight was assigned to the fourth layer (BIAS = 0), with a gradient of weights between the lower and upper for the remaining levels. For \"OBS\" and \"HYBRID\" simulations, R1 and R2 must be set as well [38]. They represent the weight of each meteorological station inside the domain in the computation of the wind field. In the current study, due to the availability of only one station (one for surface and one for upper air), these parameters must cover the entire domain [46]. For this reason, R1, referring to the surface layer, was chosen as the greatest distance from the station to the domain's farthest point, i.e., 5.7 km. For R2, referring to upper layers, the diagonal of the domain was selected, i.e., 8.5 km, considering that selected upper air stations are located outside the corresponding domain (i.e., 13 km from the source for the Italian domain and 240 km for the Cuban domain). The values of these parameters are the same in the two simulations because the domains have identical dimensions, and the surface stations are positioned identically relative to their respective southwest corners. RMAX1 and RMAX2 parameters, required for the \"OBS\" and \"HYBRID\" simulations, identify the maximum radius of influence for surface and upper data, respectively. According to the scientific literature, it is suggested to set these parameters equal to twice R1 and R2 [47].