## 7 Discussion
Likewise, wind and current do not always move in the same direction. These factors may explain the stagnation of the oil drift after 32 h and the differences in the direction of movement of some oil parts. However, we can observe the significant impact of strong wind (above 10 m/s) on the change in oil shape. Indeed, at high wind speeds (10.7-12.7 m/s), the oil is split into one big part and many smaller ones, and some of them disappeared, probably due to evaporation. The impact of wind and current on the oil-drift direction is more evident in Case #Q2. The oil moved in the same direction as wind and current after 4 and 24 h. The wind velocity of about 8 m/s (07:00, Figure 12) may have significantly impacted the change in oil shape (medium scale). It is split into many small parts, especially as to the oil tail. The oil continued changing at wind speeds of 3-6 m/s but was still present after 24 h. For Case #Q3, we observe that at a low wind velocity (below 4 m/s), the shape of the medium-scale oil only changed a little, while the small one may evolve more significantly, but it is still present on the sea surface. This result differs from Cases #Q1 and #Q2, for which the small-scale oil disappears at higher wind speeds (above 6 m/s). The change in oil shape is also observed for Case #Q3 (middle scene, Figure 14b) at wind speeds of 4-6 m/s. The impact of wind and current on the oil drift for Case #Q3 is aligned with the results observed for Cases #Q1 and #Q2. Indeed, it is not easy to determine the drift direction and distance for the large-scale oil (first scene, Figure 14a). The oil drift in the second scene (Figure 14b) stagnated due to the difference between wind and current \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Date**} & \multirow{2}{*}{**Oil Scale**} & **Time Lag** & **Oil-Slick** & **Wind** & **Current** & \multicolumn{2}{c}{**Direction**} \\  & & **between Two** & **Shift (km)** & **Speed** & **Speed** & **(Up-North Reference)** & \\ \cline{3-8}  & & **Sensors (Hour)** & **(m/s)** & **(m/s)** & **Oil Drift** & **Wind** & **Current** \\ \hline \multirow{3}{*}{\#Q1 27–28 March 2021} & \multirow{3}{*}{Large} & 24 (S-2/3) & 18.5 & 1.0–10.7 & 0.23–0.32 & SE & NW/NE/SE & SE/SW/NW/NE/N \\ \cline{3-8}  & & 8 (S-3/1) & 5.2 & 10.7–12.7 & 0.27–0.33 & NW/SW & SE & NW \\ \cline{3-8}  & & 4 (S-1/2) & 4.5 & 5.5–7.8 & 0.25–0.30 & NW & W/NW & NW/N/E \\ \cline{3-8}  & & 24 (S-2/L-8) & 12.3–12.9 & 3.0–6.0 & 0.30–0.39 & NW & NW/N & SE/SW/NW/N \\ \hline \multirow{3}{*}{\#Q3 3 September 2021} & \multirow{3}{*}{Large–Medium-small} & \multirow{3}{*}{4 (S-1/2)} & N/A & 2.6–4.4 & 0.29 & N/A & NW & NW \\ \cline{3-8}  & & & 2.95 & 3.5–6.3 & 0.26–0.27 & S & NW/NE & SE/S \\ \cline{3-8}  & & & 3.75–4.8 & 1.8–4.2 & 0.26–0.27 & NE & NE & NE/E \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Overview of the floating oil drifts off the shore of Qatar, and their relationship to surface wind and current. directions. The oil tended to move in the same direction as the current, since wind velocity (4-6 m/s) was not high enough to affect the oil movement. For the third scene (Figure 14c), the oil moved in the same direction as the wind and current, and the oil drift tended to accelerate due to the similarity of the wind and current directions. Regarding the oil spill off the coast of Mauritius, the spreading of the oil surface changed very little after 13 h with a stable wind speed of 6-7 m/s; however, the oil surface expanded significantly after 21 h with a lower wind velocity of 2-4 m/s. The dominant factor contributing to this change is presumed to be the current. The coarse spatial resolution of ERA-5 wind (\(\sim\)25 \(\times\) 25 km) and CMEM current data (\(\sim\)9 \(\times\) 9 km) may have complicated the assessment of the impacts of surface wind and current on the oil drift, especially for the oil spill off the shore of Mauritius, and when wind and current fields changed significantly, as observed for Cases #Q1 and #Q2.