# The DLR FireBIRD Small Satellite Mission: Evaluation of Infrared Data for Wildfire Assessment
## 4 Conclusions  
The results presented here are based on an inter-comparison between different sensors. Several influencing factors complicate the derivation of exact results. Nevertheless, this methodology is regarded as the most appropriate way under real-world conditions. It could be shown that the FireBIRD system shows a satisfactory performance, featuring a spatial concordance of 83% compared to MODIS and 84% compared to VIIIRS when the reference  
Figure 8: FireBIRD active fire data (derived using the MWIR method) and reference data for a fire event in New South Wales/Australia, November 2019. (**a**) shows active fires derived from two FireBIRD/HSRS overpasses (9 November 2019 and 14 November 2019), pigmented by FRP. (**b**) shows MODIS active fire data of the Aqua/Terra overpasses in closest temporal vicinity to the respective FireBIRD overpasses. (**c**) shows VIIIRS active fire data of the Suomi-NPP overpasses in closest temporal vicinity to the respective FireBIRD overpasses. Background: Stamen/OpenStreetMap shaded terrain map. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Overpasses \(\Delta\)t < 45 min**} & \multicolumn{2}{c}{**All Overpasses (\(\Delta\)t < 12 h)**} \\ \hline  & & **MWIR** & **MWIR/LWIR** & **MWIR** & **MWIR/LWIR** \\ \hline \multirow{2}{*}{True positive ratio} & M6 & 0.83 & 0.81 & 0.75 & 0.73 \\  & V1 & 0.84 & 0.84 & 0.54 & 0.52 \\ \hline \multirow{2}{*}{False negative ratio} & M6 & 0.17 & 0.19 & 0.25 & 0.27 \\  & V1 & 0.16 & 0.16 & 0.46 & 0.48 \\ \hline \multirow{2}{*}{False positive ratio} & M6 & 2.24 & 2.17 & 2.92 & 2.82 \\  & V1 & 1.78 & 1.73 & 2.17 & 2.11 \\ \hline \multirow{2}{*}{TP FRP ratio} & M6 & 1.11 & 1.97 & 1.24 & 1.95 \\  & V1 & 1.31 & 1.75 & 1.15 & 1.56 \\ \hline \multirow{2}{*}{TP mean bias (MW)} & M6 & 0.0 & 0.97 & 0.07 & 0.76 \\  & V1 & \(-\)0.03 & 0.23 & 0.0 & 0.31 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the inter-comparison between FireBIRD and the reference datasets, regarding both the subset and the complete dataset. M6 refers to the MODIS MOD14A1 product (version 6) while V1 refers to the VIIIRS VNP14A1 product (version 1). overpass occurs in close temporal proximity. FireBIRD generally detects a higher number of active fires than the reference sensors, which can be attributed to its higher spatial resolution and radiation sensitivity. The radiometric accuracy regarding FRP is high when the MWIR method is used, which is the same one as in the reference products. With this method, the bias in FRP is 11% on average compared to MODIS, regarding the subset with low temporal differences between the overpasses. The similarity is lower for the VIIIRS reference regarding the subset, accounting for a bias of 31%. This difference can be attributed to the lower expressiveness of this subset, due to a lack of available FireBIRD active fire detections. The analysis of the complete dataset, irrespective of overpass times, yields a positive bias of 15% for VIIRS. This number rises considerably when the MWIR/LWIR method is used. However, considering that the MWIR method is known to underestimate FRP, real intensity values can be regarded to range between the results of both methods. The FireBIRD data is thus found to show high similarity in results compared to the MODIS and VIIRS references, both regarding the accuracy in geometry and radiometry. Furthermore, the additional use of the LWIR band is beneficial for the derivation of FRP regarding fires with low intensity. In conclusion, FireBIRD is a highly capable system in terms of radiometric sensitivity and spatial accuracy. It enables the monitoring and analysis of individual fire events with a higher resolution than available with other Earth-observation systems. Although experimental, FireBIRD features performance parameters similar to leading satellite/sensor systems such as Aqua/Terra MODIS and Suomi-NPP/NOAA-20 VIIRS, and thus demonstrates the operability of small satellite missions.