This layer maps the mean algal bloom intensity over the selected period using the Maximum Chlorophyll Index (MCI), a line-height index sensitive to the chlorophyll fluorescence peak at 705 nm. It is computed from Sentinel-2 L2A imagery (COPERNICUS/S2_SR_HARMONIZED on Google Earth Engine) at 20 m resolution over water surfaces only. Warm colours (yellow to dark red) mark stronger, more intense blooms; blue tones indicate clear water with little to no bloom.
The Maximum Chlorophyll Index (MCI) is a line-height index that measures the chlorophyll fluorescence peak near 705 nm above a baseline drawn between the red (665 nm) and red-edge (740 nm) bands. It is optimised for detecting intense algal blooms, offering higher sensitivity at high chlorophyll-a concentrations than NDCI. In the annual-mean (range) mode, all cloud-free acquisitions within the selected period are averaged into a single composite, giving the mean bloom intensity for the interval.
| Code | Provider | Resolution | Year |
|---|---|---|---|
| WRD_SCLXX_99 | ESA / Copernicus (Sentinel-2 L2A, via Google Earth Engine) | 20 m | Time-dependent (2017 to present) |
From the COPERNICUS/S2_SR_HARMONIZED collection, MCI is computed per scene as MCI = B5 - B4 - 0.389 x (B6 - B4), where B4 is Red (665 nm), B5 Red Edge 1 (705 nm) and B6 Red Edge 2 (740 nm); the 0.389 coefficient derives from the MERIS heritage baseline (28/72). Clouds and shadows are removed via the Scene Classification Layer (SCL) and only water pixels (SCL class 6) are retained; the per-scene MCI values are then averaged over the selected period into the mean composite.