What does this model compute? This prototype uses equation-compatible implementations of the GeoGeek water-optics forward model (IOPs to Rrs), first-order atmospheric forward model, matched-model atmospheric correction, and selectable nominal rectangular or source-pinned published measured spectral response functions.
Spectral range 400–700 nm · 1 nm
Water column (V10.0) Gordon/GIOP parameterization and Lee interface approximation · Optically deep water
WATER RT reference (V10.1) Scalar 16-stream azimuth-averaged DOM with HG g=0.8, Ed-direct(0−)=1 and no Fresnel boundary. Fixed 3×3×5 RT grid; only 8 upward zenith directions. Numerically generated in-house; not externally validated.
Atmosphere Single-scattering Rayleigh and aerosol path terms with two-way direct transmittance
Sensor response Nominal rectangles by default; source-pinned S2A/S2B MSI and Landsat 8 measured SRFs optional; others nominal only
Coefficient tables Offline Float32 representation; not bitwise identical to upstream decimal tables
Validation status V10.0 regression checks and V10.1 RT self-consistency tests; no HydroLight/DISORT cross-check or independent field validation
Scientific Limitations ρTOA* is an idealized TOA reflectance proxy, not satellite-measured TOA radiance. Gas absorption, multiple scattering, adjacency effects, sun glint, surface BRDF, and shallow-water bottom effects are excluded. Forward and inverse calculations use the same first-order model. Numerical closure does not establish atmospheric correction accuracy. V10.0 defaults Sg = 0.0176 nm⁻¹ and S_NAP = 0.0123 nm⁻¹ match the historical baseline; modified slopes are explicitly experimental. WATER RT reference is azimuth-averaged scalar radiance, not the full L(z,θ,φ). IOP mismatch disables claims of a live paired model result; comparisons always use the archived matching case. RT requires assumed g=0.8 and converts bb to b. No water–air interface physics, refraction, Raman scattering or fluorescence is included. Source modules include upstream Git blob hashes. Float32 coefficient tables introduce small numerical differences. Interaction Guide Select a workspace from the top navigation. WATER RT presents fixed numerical depth, upward-angle and matched subsurface-rrs comparisons; fixed samples are not continuous measurements. The Sensitivity workspace computes finite-difference local parameter responses and selected nominal or measured sensor-band averages; it does not estimate measurement uncertainty, sensor noise, or inverse identifiability. Switch spectral quantities above the chart. Enter parameters numerically or with sliders. Use the wavelength probe, save A/B scenarios, import a compatible experiment JSON, or export CSV/JSON results. The Y-axis lock applies only to the active plot.