We have great news about our ESA project: the PRIMUS web GIS portal has just been launched and is now available for anyone to view, explore, manipulate and analyse Earth Observation data obtained by satellite remote sensing of the Atlantic Eastern Boundary Upwelling Systems (EBUS).
Now that we have completed the project’s data production phase and have started the user engagement and societal impact phase of the project, our outreach strategy is highly focused on making the data available to be freely exploitated by stakeholders and academics, foremost the ocean modelling communities. This will be done both through presenting the results on NPP to end-users and exploring how the data can be implemented and continued in operational environments in Europe and Africa (see PRIMUS Post 6 March 2024), and by making the data available on the online PRIMUS web GIS portal. To that aim, both the 25-year time series of 1 km satellite-derived NPP over all Atlantic EBUS, and the 300 m resolution NPP time-series data for the Galician Rias can now be freely accessed.
September 2019 snapshot of the high (300 m) resolution NPP data taken by the PRIMUS web GIS portal, showing spatiotemporal variations in the intensity of coastal upwelling along the Galician coast. NPP is high (orange-red) when nearshore waters are cooler, as expected in summer upwelling, and low (blue-purple) when they are warmer and oligotrophic.
We are also pleased to share that the portal includes new data on an Upwelling Index determined for the entire area of the Atlantic EBUS since 1997, and which represents an important output from PRIMUS. The Upwelling Index was calculated based on the difference between nearshore and offshore sea surface temperature (SST). The index is positive when nearshore waters are cooler, as expected for the summer upwelling season, and small or negative when upwelling of cooler water is not occurring.
Daily snapshots of the Upwelling Index between 2020 and 2023 during spring/summer (left panel) and autumn/winter (right panel) conditions taken by the PRIMUS web GIS portal, showing spatiotemporal variations in the intensity of coastal upwelling along the Galician, Iberian, and African coasts. The index is positive (red) when nearshore waters are cooler, as expected in summer upwelling, and negative when they are warmer (blue).
Why are NPP data from EBUS important?
Upwelling systems are regions characterized by an upward movement of water parcels in the water column of the ocean over a reasonably long period (several days to weeks). It happens when alongshore wind stress and the Coriolis effect combine to promote the occurrence of Ekman transport towards offshore. Once the upwelled waters reach the sunlight-illuminated upper part of the ocean, the nutrients they carry will fuel primary productivity causing phytoplankton to often bloom near the coast. As the upwelled water spreads towards the sea, it will form plume-like pigment-rich filaments which tend to mature while being transported offshore, as seen by an increase in phytoplankton biomass at the expense of the dissolved nutrients, as well as changes in species composition. Because of these combined processes, EBUS are among the most biologically productive regions of the ocean, thereby providing ecosystem, economic (including fishing and aquaculture), and recreational services to millions of people living along their coasts, especially in countries with a strategic vector of development in the economy of the sea.
Ekman transport in the Northern Hemisphere: longshore northerly winds combine with the Coriolis effect to force surface waters to move away from the coast while deeper, cooler and nutrient-rich waters upwell from beneath the thermocline to take their place (image credits: Merino & Monreal-Gómez, 2011).
In addition to the Upwelling Index, the portal also includes the SST data from which the upwelling index is calculated, and SST data specific to the offshore region. Over the course of PRIMUS, the portal will continue to be fed by new Earth Observation data such as Photosynthetically Available Radiation (PAR), crucial for advancing the existing understanding of the spatiotemporal variability of marine primary production in the Atlantic EBUS. Until then everyone is welcome to enter the portal and start exploring the already available data to create your own distribution map, which can then be exported and shared. To know more about our web data portal and start exploring our PRIMUS dataset, click here.