Simulated data for a GJ 1214-type system for the same stellar and planetary parameters as the previous two figures. The two simulations differ in their assumed gravity, metallicity (H₂O/H₂), indicated in the color legend, and cloud assumptions. In the top panel neither model has clouds. In the bottom panel, the low gravity, high metallicity model has a 10 millibar cloud that reduces the strength of its absorption features. Observations were simulated for NIRISS SOSS with no noise floor and binned to R = 100. Top panel observations were simulated with 40 transits (80 hr). Bottom were simulated with 100 transits (200 hr). Some error bars are too small to see. The red error bars represent the proposed ±20 ppm noise floor for NIRISS (Greene et al. 2016).