Transit spectra computed for the three innermost planets of the TRAPPIST-1 system calculated from 3D GCM simulations, assuming a 10 bar H₂O atmosphere (+1 bar N₂). The red and blue spectra are calculated for the wavelength coverage of NIRISS SOSS and NIRSpec PRISM, respectively. The 1σ error bars are calculated using the JWST Cycle 1 observation program (for more details, see Section 3.5.2). The transit spectra are in transit depth units (the transit depth is equal to zero at the surface).