Satellite Revisit Gap — Deforestation Detection Latency

Satellite Monitoring

Revisit interval 5 days

Cloud-cover probability 40%

Minimum mapping unit 9 cells

Simulation speed 2 days/s

Live Status

Clearing in progress…

Day since onset

0.0 d

Cleared area

0 ha

Passes: clear / cloud

0 / 0

Detection latency

—

How it works

Optical satellites (Sentinel-2 ≈5 days, Landsat ≈16 days) only image a given tile on a fixed revisit interval T. On any given pass the tile may be hidden under clouds with probability p — a real, persistent limiter for tropical forest monitoring, where cloud cover regularly exceeds 60–80%.

P(pass is clear)      = 1 − p
E[passes until clear] = 1 / (1 − p)      (geometric distribution)
E[latency to 1st clear pass] ≈ T / (1 − p)

Even a clear pass isn't enough: single-pixel noise and classification error mean an operational pipeline only confirms a clearing once the contiguous cleared area exceeds a minimum mapping unit (MMU) — real programs like Global Forest Watch use MMUs on the order of a Landsat/Sentinel pixel cluster, roughly 0.1–1 ha, to suppress false alarms.

Revisit interval — days between satellite passes over this tile.
Cloud-cover probability — chance any single pass is blocked and produces no usable image.
Minimum mapping unit — contiguous cleared cells required before a clear pass counts as a confirmed detection.
Simulation speed — how many simulated days elapse per real second.

The clearing itself spreads outward from a seed cell at a steady rate, independent of monitoring — the simulator's point is the gap between when clearing starts and when the monitoring pipeline actually confirms it, which is exactly the latency that limits how fast an early-warning or enforcement response can act.

Forest canopy Cleared land Satellite

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