Reflect development

Reflect is a static browser experiment at /reflect/. Page markup is in _pages/reflect.html, styles in assets/css/reflect.css, and documentation in scripts/REFLECT.md.

Ethos

Keep the project lightweight: native ES modules, Canvas 2D, typed arrays and one short-lived Web Worker. Avoid frameworks, remote assets, image textures and runtime dependencies unless a concrete benefit justifies their cost.

• Preserve the supplied SpeedyWeather C45 coefficients and quadrature. See scripts/test_reflect.mjs for independent Julia reference values.
• Calculate radiation at the full selected grid resolution (up to 256 × 256). Adapt drawing detail to screen pixels rather than reducing physics resolution.
• Cache angle-independent BRDF coefficients and static geometry/Path2D textures. Reuse frame and shadow buffers; never retain a per-cell history for every step.
• Integrate 1440 midpoint intervals independently of playback speed. Terminate workers after transferring results, and invalidate stale computations on edits.
• Cap canvas pixel count and device pixel ratio. Keep animation and DOM update rates separate. Release object URLs after CSV downloads.
• Procedural surface objects are decorative; the shadow model uses terrain heights, not vegetation geometry. Keep scientific assumptions visible.
• Fit desktop controls, landscape, irradiance gauges and energy totals in one viewport. Use dialogs for detailed inputs, and permit scrolling on small screens.

The terrain brush applies a bounded Gaussian lift over a circular neighborhood. Its peak is 100 m, its radius scales with grid size, and its edge reaches zero. Painting changes physical inputs and recalculates the day.

Planet lab (October 2026)

The main /reflect/ route now hosts the spherical energy balance model. The terrain implementation above remains at /reflect/terrain/. See scripts/REFLECT.md for the planet model and REFLECT_TERRAIN.md for terrain.

Planet modules use the globe- prefix. Its persistent worker integrates daily steps and returns pooled Float32 snapshots; terminate it when replacing the experiment or leaving the page. Keep at most one advance in flight and cap batches, so controls can interrupt computation. Store bounded scalar history, not globe frames. The default reduced spherical grid has 50,932 cells at ~100 km.

Scattering means redistribution of sunlight, not heat diffusion or clouds. Its Gaussian approximation must preserve area-weighted power and positivity, including across longitude seams and polar row changes. All means use true spherical cell areas. Changes to orbit, CO₂ or albedo must retain the unchanged reference; never recalibrate an experiment’s forcing away.

Integrate three global deterministic FaIR thermal responses using ECS 2.5/3/4°C per doubling. Feed CO₂ forcing plus area-weighted absorbed-shortwave change into the three-layer equations, never the evolving imbalance itself. Use the cached daily matrix exponential; keep the approximate regional pattern separate and adjust its mean to the global FaIR result. Label the envelope as sensitivity scenarios, not a transient probabilistic confidence interval. Show perturbation imbalance and total seasonal imbalance distinctly. Local albedo edits must preserve the experiment’s temperatures and history. The baseline and physical C45 inputs are prescribed; the Natural Earth mask supplies real coastlines but vegetation and ice remain illustrative. Preserve the Jin ocean coefficients from the pinned SpeedyWeather gm/albedo source, its attribution and EUPL licence. Diagnose the roughness input explicitly from Cox–Munk wind, and clamp the final mixture.

Native WebGL draws the globe, with a cached low-resolution ray-cast Canvas fallback. Keep graphics and physics independent, cap pixel buffers, and draw at most 30 times per second during annual display rotation; stop on pause, hidden pages, editing or reduced-motion preference. Static surface textures need one upload; only quantitative map modes change each snapshot. Autostart uses a dated NOAA snapshot from co2-baseline.mjs and today’s season. Never present that cached value as a live feed, or the equilibrium initialisation as historical climate. The future albedo game should use this same model and keep its educational assumptions visible.

Boundary-data checkpoint

See scripts/REFLECT_NEXT.md before continuing. SpeedyWeatherAssets boundary binaries and conversion metadata are prepared at a pinned source commit, but runtime integration is pending. Keep learned C45 for land; the prescribed albedo asset must not replace it. Respect snow mass-to-water-depth conversion, monthly missing masks, coordinate ordering and documented temperature proxies. The user stopped offline simulations; do not resume them without a new request.