Pelagic sargassum accumulations along the shoreline and nearshore waters in La Parguera, Puerto Rico from 2015-09-16 to 2022-01-22

Massive sargassum influxes into the Wider Caribbean Region and West African coast have negatively affected both social and ecological systems since 2011. Current monitoring efforts using satellite data are being conducted but are mainly limited to offshore waters. This research attempts to address the literature gap by developing a method to characterize sargassum accumulations along the shoreline and nearshore waters, and to assess their spatial and temporal dynamics. Using the online Google Earth Engine platform, we analyzed Sentinel-2 MultiSpectral Instrument (MSI) satellite imagery for sargassum occurrence from 2015-09-16 to 2022-01-22 in La Parguera, Puerto Rico. A combination of MSI reflectance bands and several vegetation and water quality indexes were used with a Random Forest classification algorithm. Field data was collected to calibrate and validate the classification product. Our classification model was able to identify different stages of the sargassum decaying process in the shoreline (e.g., fresh sargassum, decomposing sargassum, and sargassum brown tide) along with other non-sargassum cover classes (e.g., water, mangroves, and clouds). Sargassum accumulation hotspots (SAHs) that persisted throughout the study period were identified and their spatial and temporal dynamics were assessed.

The data package consists of the following datasets:
- LeonPerez.et.al_TrainingAndValidation.shp: Shapefile showing the training and validation data used.
- LeonPerez.et.al_CoverClassPersistence.tiff: Raster showing the cover classes that persisted for each pixel throughout the timeseries.
- LeonPerez.et.al_SAHLocation.shp: Shapefile showing the location of the three SAHs analyzed.
- LeonPerez.et.al_SAHTimeseries_IslaCueva.txt: Timeseries of the area covered by each of the six cover classes in Isla Cueva SAH.
- LeonPerez.et.al_SAHTimeseries_IslaGuayacan.txt: Timeseries of the area covered by each of the six cover classes in Isla Guayacán SAH.
- LeonPerez.et.al_SAHTimeseries_LaPitahaya.txt: Timeseries of the area covered by each of the six cover classes in La Pitahaya SAH.