NIRSpec reflectance spectra of Ganymede surface. Left: leading hemisphere. Right: trailing hemisphere. Averages over bins of latitudes are plotted, as labeled in the upper left panels. Thermal emission was not subtracted, so reflectance values are significantly overestimated at λ > 4.9 µm (dashed lines, see text). The absolute scale is also inaccurate for the highest latitudes due to PSF filling effects (see text). Spectral identifications of the three H₂O Fresnel peaks (2.95, 3.1 and 3.2 µm), absorption bands of H₂O₂ (3.5 µm) and CO₂ (4.26 µm) are indicated. The absorption signatures at the position of the ¹³CO₂ band (4.38 µm), and those at 3.426 and 3.51 µm indicated by question marks, are most likely spurious (see text). The feature seen in absorption at 4.995 µm at the 2% level is not of Ganymede origin as it is not observed in MIRI spectra. The spectral continuum is dominated by water ice for the mid and high latitudes of the leading hemisphere, with local maxima at 3.65 and 5 µm (H₂O inter-bands) and a minimum at 4.45 µm (H₂O absorption band). In other regions, the higher concentration of non-ice materials (minerals, etc.) induces the increase of the reflectance with wavelength, the reduction of the amplitude of the water ice spectral features, and the shift of the water inter-band to 3.9 µm.