## 4 Simulation of the Meteosat Third Generation Imager Fire Channel Potential
\begin{tabular}{c} Core \\ channels \\ \end{tabular}  & \begin{tabular}{c} Central \\ wavelength \\ micron \\ \end{tabular}  & \begin{tabular}{c} Width \\ (FWHM) \\ \end{tabular}  & \begin{tabular}{c} Spatial \\ sampling \\ \end{tabular}  & \begin{tabular}{c} Central \\ wavelength \\ micron \\ \end{tabular}  & \begin{tabular}{c} Width \\ (FWHM) \\ micron \\ \end{tabular}  & \begin{tabular}{c} Spatial \\ sampling \\ (km) \\ \end{tabular}  & \begin{tabular}{c} Central \\ wavelength \\ micron \\ \end{tabular}  & \ \begin{tabular}{c} Width \\ (FWHM) \\ \end{tabular}  & \begin{tabular}{c} Spatial \\ sampling \\ (km) \\ \end{tabular}  \\ \hline VIS 0.4 & & & & & & & & 0.444 & 0.06 & [11] \\ \hline VIS 0.5 & & & & & & & 0.510 & 0.05 & [11] \\ \hline VIS 0.6 & 0.7 & 0.35 & [11] & 2.5 & 0.635 & 0.08 & [11] & 3.0 & 0.640 & 0.08 & [11] \\ \hline VIS 0.8 & & & & 0.81 & 0.07 & [11] & 3.0 & 0.865 & 0.07 & [11] & 1.0 \\ \hline VIS 0.9 & & & & & & & 0.914 & 0.06 & [11] & 1.0 fires in Benin (West Africa) in December 2002 and over Portugal in August 2003, as already used in [15]. The spectral bands of the BIRD MIR and TIR channels are similar to those of MTG-I/FCI (see Table 7). BIRD had a spatial resolution of 370 m with a sampling step of 185 m (due to the used staggered line array detectors and double sampling, used in the HSRS of BIRD (and also in the IR sensors of TET-1 and BIROS), the ground sampling step is \(\%\) of the linear pixel size, which is, for instance, explained in detail in [6]) and a high saturation level of \(\sim\)600 K, allowing an adequate simulation of MTG-I/FCI images. For the simulation, a 1 km sampling mode and a 2 km sampling mode of the MTG-I/FCI MIR/TIR fire application channels were assumed. Numerous fires in Benin were imaged by BIRD on 1 December 2002. The scene, shown partly in Figure 8, is dominated by small fires. The scene has 1024 \(\times\) 2700 BIRD pixels with its center at 9.3\({}^{\circ}\) N, 1.8\({}^{\circ}\) E. The expected resolution of the MTG-I/FCI at this latitude is approximately 1.0 \(\times\) 1.0 km\({}^{2}\) in the 1 km mode and 2.0 \(\times\) 2.0 km\({}^{2}\) in the 2 km mode (see Table 8). The MTG-1/  
The pixel sizes and the pixel area for the MTG-I/FCI MIR/TIR fire application channels in the 1 km mode and in the 2 km mode are presented in Table 8 as a function of the latitude, considering the pixels in the nadir part of the east-west scans (the pixel sizes and areas at the scan edges of MTG-I/FCI will be larger). All hot pixel signals in the simulated MTG-I/FCI Benin image are far from the FCI \"maximum signal\" temperatures for the fire application channels--presented in Table 7--both in the 1 and 2 km sampling modes, i.e., the respective maximum pixel temperatures simulated for the Benin scene are 401 K or 361 K in the MIR channel and 318 K or 315 K in the TIR channel. The fire detection potential of a sensor can be characterized by the minimum FRP of the hot clusters. While BIRD data allow detecting fires with an FRP as low as 0.3 MW, the minimum FRP of the detected fires for MTG-I/FCI in the simulated scenes was 6.6 MW in the 1 km sampling mode and 48.6 MW in the 2 km sampling mode, using the FRP equation, Equation (1), of Section 2.2 of this paper. As a result, significantly fewer hot clusters could be detected in the simulated MTG-I/FCI images (122 in the 1 km mode and 48 in the 2 km mode) in comparison to 516 hot clusters which were detected by BIRD (see Table 8 below). Nevertheless, the decrease in the total FRP summarized for all detected fires in the whole scene is not so significant: 11.0 and 9.6 GW for the 1 or 2 km MTG-I/FCI sampling modes compared to 11.7 GW for BIRD. This result can be explained by the following two effects:  
Figure 9: Simulated MTG-I/FCI MIR image fragments with 1 km and 2 km GSDs. The original BIRD image fragment shown in Figure 8 corresponds to the center squares of these two images. 1.