## 2 Materials and Methods
### Dataset
#### 2.1.2 Spectral Bands and Indices  
The Sentinel-1 satellite is equipped with different polarization modes, encompassing both vertical and horizontal transmission and reception. Within this dataset, the satellite imagery features dual polarization, specifically vertical transmit and vertical/horizontal receive (VV + VH). This configuration provides enhanced information, contributing to the improved detection of water while simultaneously maintaining computational efficiency. On the other hand, Sentinel-2 comprises a total of 13 spectral bands, offering a comprehensive range of information, as detailed in Table 2. Additionally, Figure 2 presents a visual representation of each spectral band for both Sentinel satellites. For flood inundation mapping, certain spectral bands are especially preferred. Notably, the visible light bands (RGB) are highly favored for their sensitivity to surface reflectance, rendering them effective in distinguishing various land-cover types, including water bodies. Furthermore, the near-infrared (NIR) band is frequently employed, as water bodies exhibit strong absorption of near-infrared light, facilitating a pronounced contrast between water \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Band** & **Resolution** & **Central Wavelength** & **Description** \\ \hline Band 1—Coastal & 60 m & 443 nm & Band 1 captures the aerosol properties in coastal zones, which aids in assessing water quality. \\ Band 2—Blue (B) & 10 m & 490 nm & Band 2 captures the blue light in the visible spectrum and is useful for soil and vegetation discrimination and identifying land-cover types. \\ Band 3—Green (G) & 10 m & 560 nm & Band 3 captures the green light in the visible spectrum, which provides good contrast between muddy and clear water, and is useful for detecting oil on water surfaces and vegetation. \\ Band 4—Red (R) & 10 m & 665 nm & Band 4 captures the red light in the visible spectrum, which is useful for identifying vegetation and soil types, and differentiating between land-cover types. \\ Band 5—RedEdge-1 & 20 m & 705 nm & Band 5, 6, and 7 capture the spectral region within the red edge where vegetation has increased reflectance and are useful for classifying vegetation. \\ Band 7—RedEdge-2 & 20 m & 740 nm & Band 8 captures light in the near-infrared spectrum and captures the reflectance properties of water, so is useful for discriminating between land and water bodies. \\ Band 8—Near-Infrared & 10 m & 842 nm & Band 8 captures light in the near-infrared spectrum at a longer wavelength, providing additional sensitivity to vegetation reflectance, so is useful for vegetation classification. \\ Band 9—Water Vapor & 60 m & 945 nm & Band 9 captures light in the shortwave-infrared spectrum and is useful for detecting atmospheric water vapor. \\ Band 10—Cirrus & 60 m & 1375 nm & Band 10 captures light in the shortwave-infrared spectrum and is sensitive to cirrus clouds, so can be useful for cloud removal. \\ Band 11—Shortwave- & & & Band 11 and 12 capture light in the shortwave-infrared spectrum, and are sensitive to surface moisture, so are useful for measuring the moisture content of soil and vegetation, as well as discriminating between water bodies and other land types. \\ Band 12—Shortwave- & 20 m & 1610 nm & Band 12—Shortwave-Infrared spectrum, and are sensitive to surface moisture, so are useful for measuring the moisture content of soil and vegetation, as well as discriminating between water bodies and other land types. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Descriptions of each spectral band of Sentinel-2. and non-water regions. The shortwave-infrared (SWIR) bands are instrumental in capturing substantial information pertaining to surface moisture and are attuned to variations in water content.