latest pass · — — auto-updating
NDCI · chlorophyll NDCI — a chlorophyll proxy from the red-edge vs red bands. Higher means more algae; a high reading is the bloom signal.
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— percentile · all-time
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NDWI · water NDWI — a water index from green vs near-infrared. High means open clear water; it falls as surface scum or algae cover the surface.
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True-colour Sentinel-2 image of the Reflecting Pool True colour
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NDCI chlorophyll map of the Reflecting Pool NDCI
pool NDCI
clearbloom
NDWI water map of the Reflecting Pool NDWI
pool NDWI
lowhigh
NDCI · chlorophyll (B5 − B4) / (B5 + B4)
Red-edge vs red. Chlorophyll absorbs red and reflects red-edge, so the index climbs with algae density. This is the headline reading.
NDWI · water (B3 − B8) / (B3 + B8)
Green vs near-infrared. High over open water; it drops as scum or floating mats break up the surface.

A bloom reads as NDCI rising while NDWI falls — more chlorophyll, less clear water surface.

Each frame is one cloud-masked Sentinel-2 pass; the pool is colour-mapped over a greyed-out Mall. Percentiles rank the value against every clear pass since 2015, and the shaded chart band is that month's 25th–75th-percentile range.

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