Mudflat (temp) - Intertidal flats with deposited mud - ecosystem component from the WIO Symphony tool

Tidal areas were extracted from a 30-m resolution global model (“The global distribution and trajectory of tidal flats”, 2019) based on Landsat data from 2002-2016. Presence of tidal flats were extracted into a 250-m raster, then masked >20 m depth using GEBCO depth data mapped to a 250-m grid on the African West coast (thus removing suspected artefacts in the remote sensing). The 250-m raster data was aggregated to a 1-km grid, generating a proportional value for each 1-km pixel. Finally, it was divided into tropical and temperate areas by using the yearly average SST (Sea Surface Temperature) from Copernicus data to model the temperate/tropical zone with a linear ramp-up starting at 25.5 °C (e.g. temp = 0, trop = 1) ending at 23 °C (e.g. temp =1, trop = 0) Known limitations: This layer represents tidal flats, rather than tidal mud flats, due to poor mud data at the resolution of tidal flats along the coast. Further, it is known that the tidal flat model has erroneously classifiedmuddy waters/river plumes as tidal flats in some locations. The Gebco depth model was used to mitigate this problem on the West African coast, but in the WIO region the depth model was not of high enough quality along the coastlines, often claiming deeper depths than observed in high resolution imagery.