Urban Heat Island Adaptation Lab

Heat Wave Conditions

Rural baseline temperature 35 °C

Adaptation Strategies

Cool-roof retrofit coverage 20%

Urban tree canopy 15%

Reflective pavement coverage 10%

City Readouts

City air temp

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UHI intensity ΔT

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Heat-stress risk

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🏙️ Cool roofs

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🌳 Trees planted

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How it works

Each building's roof reaches a steady-state surface temperature set by a simplified surface energy balance: absorbed solar radiation must equal convective + radiative heat loss to the air.

ΔT_surface = I·(1 − albedo) / h

I  = solar irradiance (≈950 W/m² on a clear summer day)
h  = combined convective+radiative loss coefficient
albedo: dark roof/asphalt ≈ 0.12, cool roof/light pavement ≈ 0.65

A dark conventional roof (low albedo) absorbs far more sunlight than it can shed, running many degrees hotter than the surrounding rural air — the core cause of the urban heat island (UHI). Retrofitting a roof with reflective "cool roof" coatings raises its albedo and collapses this excess almost linearly.

Tree canopy cooling ≈ 0.08 °C per % canopy cover
(shading + evapotranspiration, empirically ~0.6–1.6 °C per 10% canopy)

City air temp = T_rural + 0.5·⟨roof excess⟩ + 0.3·(pavement excess) − canopy cooling

Each building in the grid is independently retrofitted or not — the coverage slider selects which fraction of the ~130 buildings get a cool roof, using a fixed per-building priority order so the city updates smoothly rather than reshuffling.
Trees are added to open street/park tiles the same way, up to the canopy coverage percentage.
Building colour maps that building's own roof temperature: blue (cool) → white → red (hot).

This mirrors real municipal adaptation programs (NYC CoolRoofs, LA's cool-pavement pilots): a combination of albedo, vegetation and pavement measures is what actually bends a city's heat curve, not any single intervention alone.

Cool building Hot building Tree canopy

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