This layer shows water transparency (Secchi disk depth) averaged over the selected period, expressed in meters. It is derived from Sentinel-2 Surface Reflectance imagery (ESA/Copernicus, 10 m) using the blue-to-red band ratio. Warm colours (red, orange) indicate turbid, opaque water; cool colours (turquoise, blue) indicate clear water with high visibility depth.
The Secchi disk depth (SDD) estimates water transparency, the depth at which a submerged target ceases to be visible. This layer computes the mean SDD over the selected period from Sentinel-2 optical imagery.
| Code | Provider | Resolution | Year |
|---|---|---|---|
| WRD_S2XXX_99 | ESA/Copernicus (COPERNICUS/S2_SR_HARMONIZED) | 10 m | 2017-present |
For each Sentinel-2 acquisition in the selected period, SDD is estimated as SDD = a · ln(B2 / B4) + b (B2 = Blue ~490 nm, B4 = Red ~665 nm; a = 1.7, b = 1.6), clamped to 0-30 m. Cloud and shadow pixels are removed via the SCL band and only water pixels are retained; the valid acquisitions are then averaged into a single mean composite for the period.