Sargassum Floating Algae Index Detection - Venµs

Alternative Floating Algae Index (AFAI) maps of coastal AFAI Sargassum detection derived from VENµS multispectral imagery across five Caribbean zones (northern–southern Yucatán, northern–southern Guadeloupe, Martinique) over 2022–2024.

The following variables are provided at a 4m ground resolution and every 2 days :

• AFAI_raw : raw spectral index, computed from VENµS surface reflectance bands B7 B10 B12.
• AFAI_landfree_cloudfree : same field after masking land, cloud and negative reflectances.
• AFAI_deviation : AFAI deviation from local background and its denoised (gaussian filtered) version AFAI_deviation_denoised.
• AFAI_detection : pixels whose index value is greater than a μ + 3,5σ threshold, where μ and σ are respectively mean and standard deviation of AFAI_deviation_denoised field for every scene ; other is set to 0 if water, Nan if masked.
• AFAI_detection_bin : binary classification of presence (1) or absence (0) of sargassu
• RGB