## 3 Results and Discussion
### CO, BC and Wind Analysis  
We elaborate here on the above analyses by demonstrating the capability of Sentinel to track fire-generated products such as carbon monoxide. In this case, fires were observed using Sentinel-2 and CO emissions through the recently launched Sentinel-5, which carries TROPOMI.  
Fires burning in the plantation forests in the southern Cape, as captured by Sentinel-2 imagery on 12 October 2018, are shown in Figure 7). The exploitation of SWIR, NIR and the red bands make it possible to detect active fires and the resultant smoke plume rising into the atmosphere, as can be seen from Figure 7a. The Sentinel-2 imagery was captured during the occurrence of this fire event; otherwise, this sensors' 5-day temporal cycle may limit the detection of active fires. As previously stated, all currently obtainable active fire detection products are derived from coarse spatial-resolution sensors of not less than 250 m, presenting a serious challenge for detecting smaller fires [84]. Such fires are often less damaging than bigger ones, but they still contribute to ecological and atmospheric dynamics [42]. In agreement with [PERSON] et al. [84], Sentinel-2 fine-scale product would assuredly enhance the amount of the total burned area, when cloud detection as the major source of commission errors was improved.  
Forest fires emit several products of combustion into the atmosphere including trace gases such as CO [85]. In this regard, the CO column density during the study period was mapped over South Africa using Sentinel-5 with the results displayed in Figure 7b. The figure shows that the CO concentrations were highest over the study area, with small red patches scattered across the country and medium-low to medium-high (yellow/purple) densities recorded in the northeastern parts. The time series of CO column density, which narrowed over the study area from 5 July 2018 to 20 May 2020, is displayed in Figure 7c. During this period, CO had a column density averaging 0.023 mol/m\({}^{-2}\). The exceptional increase in CO from 0.038 mol/m\({}^{-2}\) on 26 October 2018 to 0.083 mol/m\({}^{-2}\) on 27 October, and peaking at 0.098 mol/m\({}^{-2}\) on 28 October, coincides with a prominent fire that consumed many hectares of plantation forest in this area. Again, a marked increase in CO from 0.054 mol/m\({}^{-2}\) on 2 November 2018 to 0.094 mol/m\({}^{-2}\) on 3 November 2018 is noted.  
Figure 6: Burn severities in various terrain conditions; (**a**); Fire smoke recorded during fire event with young plantations in 2018 (**b**) Active fire plume; (**c**) Village adjacent to forest affected by fire; (**d**) Sawmill damaged by fire. (SA Forestry [26; 27]).  
These patterns are consistent with fire events in succession, first in late October and the second at the beginning of November [26]. This means that there is a lag time of 2 days.  
We extended the above analysis by analyzing black carbon as well as surface wind speed over the fire-affected region, and the results are shown in Figure 8. The surface winds were used to identify the dispersion direction of the biomass burning plume produced by the fire event. The observations show that there are higher concentrations of BC (1.6 \(\times\) 10\({}^{-8}\) kg/m\({}^{3}\)) that decrease from the central burned area over the southern Cape (see Figure 8a). This observation corroborates CO column density captured by the Sentinel-5 as displayed in Figure 7b above. Wind speed appears to be stronger from sideways but weakens towards the studied area, converging southwards. Our findings are consistent with FSA [26] in that extreme winds with gusts of up to 100 km/h raged some areas of the Garden Route, while areas around George had weaker winds (Figure 8b). This implies that the fire plume persisted over the affected area and slowly dispersed towards the coast.