3.2.1.3

Tweaked shade calc
Updated About and FAQ sections

assets/js/physics.js

@@ -12,7 +12,7 @@
 //    calcIndoorTempPass(TaArr, globArr, elevArr, buildingType)  passive indoor temp
 //    calcManagedIndoorTempPass(TaArr, globArr, elevArr, buildingType) managed indoor temp
 //    calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType, ventilated, speedMph)
-//    calcShadeAirTemp(Ta, effectiveRad, va, elev, shade)  per-env shade air temp
+//    calcShadeAirTemp(TaEnv, effRadEnv, va, elev, shade)  per-env shade air temp
 //    vaporPressureHpa(Ta, RH)              Magnus formula - hPa
 //    solarElevationDeg(lat, lon, dateUTC)  NOAA simplified solar position (-)
 //    calcTmrt(Ta, dirRad, diffRad, globalRad, solElev)  Mean radiant temperature
@@ -476,21 +476,25 @@ export function calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType = 'c
 // Estimates the AIR temperature you'd actually experience sitting in
 // the typical shade of the selected Solar Model - NOT the felt temp.
 //
-// The official Air column is the standardised open-ground, 2 m,
-// shaded-screen value for a ~2 km model grid cell. A real sitting
-// spot is a sheltered sun-trap: surrounding surfaces (walls, sand,
-// rock) re-radiate heat into the still air pocket, while wind mixing
-// pulls the pocket back toward the official reading. The kind of
-// shelter and the heat of the surroundings differ by environment,
-// which is what the per-env `shade` block captures.
+// Baseline: this builds on the SAME environment air temp that SunSoak
+// uses - TaEnv = Ta + env.taOffset - so every Solar Model's air-temp
+// shift (urban heat island, forest/river evapotranspiration cooling,
+// desert baking) flows through here automatically and the two columns
+// can never drift out of sync. On top of that env baseline we add only
+// the LOCAL sun-trap effects: surrounding surfaces (walls, sand, rock)
+// re-radiate heat into the still air pocket, while wind mixing pulls
+// the pocket back toward the ambient reading. Crucially the sun-trap
+// warming is driven by the environment-REDUCED radiation, so a forest
+// canopy shades the sun-trap just as it shades the person.
 //
 // IMPORTANT: this is an air-temperature nudge, deliberately gentle.
 // The radiant load of direct sun is already handled by Tmrt/SunSoak,
 // so we do NOT re-add it here - that would double-count the sun.
 //
-//   shade.offset  - base air-temp delta for this environment's shade (-C).
-//                   Warmer for urban/desert (heat island, baking ground),
-//                   cooler for river/forest (evaporative, canopy shade).
+// The environment air-temp shift is NOT re-specified here - it lives in
+// env.taOffset and reaches us via the TaEnv passed in as `Ta`. The shade
+// block only carries the two local micro-effects:
+//
 //   shade.shelter - 0-1 wind shelter. High = enclosed (canyon, canopy),
 //                   so wind mixing has little effect. Low = breezy
 //                   (open water, single beach umbrella).
@@ -500,8 +504,13 @@ export function calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType = 'c
 //                   still air warms on a sunny hour.
 //
 // Behaviour: a calm sunny hour in a sheltered, sun-baked environment
-// reads a degree or two above official Air; a windy or overcast hour
-// collapses back toward it.
+// reads a degree or two above the environment air temp; a windy or
+// overcast hour collapses back toward it. Cooling models (forest,
+// river) sit below official Air because their taOffset already has.
+//
+//   TaEnv        - environment air temp (Ta + env.taOffset), the shared
+//                  SunSoak baseline. Passed in as the `Ta` argument.
+//   effectiveRad - environment-REDUCED radiation reaching the sun-trap.
 // -------------------------------------------------------------------
 export const SHADE_K_SUN  = 1.5;   // surface-warming strength (per full-sun, fully sun-baked)
 export const SHADE_K_WIND = 0.15;  // wind-mixing strength (per m/s, fully exposed)
@@ -512,9 +521,9 @@ export function calcShadeAirTemp(Ta, effectiveRad, va, elev, shade) {
   const daytime = (elev != null && elev > 0) ? 1 : 0;
   const sunTerm  = SHADE_K_SUN  * (shade.sun ?? 0)        * rad * daytime;
   const windTerm = SHADE_K_WIND * (1 - (shade.shelter ?? 0)) * Math.max(0, va || 0);
-  const adj = (shade.offset ?? 0) + sunTerm - windTerm;
-  // Keep the nudge sane - this is air temp, not a felt-temp delta.
-  return Ta + Math.max(-5, Math.min(6, adj));
+  const adj = sunTerm - windTerm;
+  // Local sun-trap nudge only - the env air-temp shift is already in Ta.
+  return Ta + Math.max(-4, Math.min(5, adj));
 }
 
 // -- FUTURE FEATURE v2: Pets Profile - Fur Temperature & Heat Stress ----------