# Near Real-Time Extracting Wildfire Spread Rate from Himawari-8 Satellite Data
## 4 Results
### Near Real-Time FSR  
Using Equation (3), the difference between the FSD and the RWD for Esperance wildfire (36 time periods) were calculated. The number of time periods falling in different difference intervals were counted (Table 1). The FSR of 30 time periods with differences (\(\triangle\)) lower than 22.5 degrees were calculated in three directions. The extracted direction was FSD and the south and east directions were calculated by decomposing wind speed.  
Figure 3: Variation in the burned area at each period computed as the difference in burned area between two consecutive 10 min time periods.  
Compared with the CSIRO GFS model, the H8-FSR under-estimated the FSR in the south, east and extracted directions (MBE = \(-\)0.52 m/s, \(-\)0.52 m/s and \(-\)0.75 m/s, respectively) (Table 2) with a MAPE of 43.33%, 35.53% and 33.20% (Table 2). The statistical metrics demonstrated a better agreement between the model estimates in the east and extracted directions compared to the south direction (Table 2 and Figure 4). The south direction demonstrated a larger MAPE (43.33%), a smaller R\({}^{2}\) (0.35) and a regression line that deviated from the 1:1 ideal line. However, the RMSE (0.80 m/s) was found to be smaller than the RMSE of the other two directions. Figure 4c demonstrates a less scattered distribution of dots, while the maximum FSR extracted from the Himawari-8 data (2.2 m/s) in the south direction was smaller than the FSR extracted from Himawari-8 data in the east and extracted directions. These may account for the low RMSE value.  
Figure 5 indicates that the FSR extracted from the Himawari-8 data is very close to the FSR estimated from the CSIRO GFS model for the 10-min time period from 11:00 to 12:40, especially in  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Difference**} & \multicolumn{5}{c}{\(\triangle\)(\({}^{\circ}\))} \\ \cline{2-6}  & **0–5** & **5–10** & **10–15** & **15–22.5** & **>22.5** \\ \hline
**Number of time periods** & 13 & 7 & 6 & 4 & 6 \\
**\% of Total** & 36.11 & 19.44 & 16.67 & 11.16 & 16.67 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Statistical summary of the differences between the FSD and RWD.  
Figure 4: Scatterplots between the FSR extracted from Himawari-8 data (V\({}_{\text{H-8}}\)) and the CSIRO GFS model (V\({}_{\text{M}}\)) in three different directions. The short dash lines are 1:1 lines and the solid lines are linear regression lines.  
the east direction (Figure 5b). A large deviation occurs from 12:50 to 15:10 when CSIRO GFS model generally obtains higher FSR. However, the FSR derived from the Himawari-8 data is higher than the FSR estimated from the CSIRO GFS model at 15:30\(-\)15:40 and 15:50\(-\)16:00 periods.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **Extracted Direction** & **East Direction** & **South Direction** \\ \hline
**MBE (m/s)** & \(-\)0.75 & \(-\)0.52 & \(-\)0.52 \\
**MAPE (\%)** & 33.20 & 35.53 & 43.33 \\
**RMSE (m/s)** & 1.17 & 0.92 & 0.80 \\
**R\({}^{2}\)** & 0.54 *** & 0.61 *** & 0.35 *** \\ \hline \end{tabular}
\end{table}
Table 2: Quantitative comparison of the FSR extracted from Himawari-8 data and CSIRO GFS model. MBE, Mean Bias Error, MAPE, Mean Absolute Percent Error; RMSE, Root Mean Square Error and R\({}^{2}\), coefficient of determination (*** _p_-Value = 0.00).  
Figure 5: Time series of FSR extracted from the Himawari-8 data (V\({}_{\text{H-8}}\)) and the CSIRO GFS model (V\({}_{\text{M}}\)).