POSTER SESSION 1
15:30–17:30, Monday, September 14
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1210 | POSTER 21
USING GOES TO ESTIMATE SARGASSUM AGGREGATION DRIFT VELOCITY
Sargassum algae are proliferating at the surface of the Tropical Atlantic Ocean. Monitoring their drift and forecasting their future trajectories is key to facilitate disaster management and mitigate their impact at the coast. Successive satellite detections can be used to track Sargassum aggregations. The high temporal frequency (10 min) of the ABI sensor on board the GOES geostationary satellite strongly increases the probability to observe the ocean surface compared to low-orbiting sun-synchronous satellites. This data thus provides potentially rich information on Sargassum drift. In this study, GOES-ABI and MODIS data are used to automatically track Sargassum aggregations in the Western Tropical Atlantic (5-20°N, 50-70°W), over the period 2022-2024. GOES-retrieved velocity is consistent with MODIS for the same aggregations (complex correlation of 0.890+0.004i). GOES can retrieve twice as many velocity vectors as MODIS on average (~1300 yearly retrievals against ~600).
Regressions of Sargassum drift against collocated surface drifters drift and wind yielded a total windage of ~0.03, consistent with previous study. When regressing Sargassum velocity against wind, the best model is obtained with a non-linear effect of wind. This contrasts with regressions of undrogued SVP drifters velocity against wind, that show a lower wind effect that remains linear. This variable windage has impact on transport forecast. This study demonstrates the feasibility of the automatic tracking of Sargassum aggregations at daily scale using GOES, and improves our understanding of the drift response to current and wind.
Leo Berline, MIO/AMU, [email protected], https://orcid.org/0000-0002-5831-7399
Audrey Minghelli, LIS, [email protected]
Boubaker Elkilani, LIS, [email protected]
Jacques Descloitres, ULille, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
