[NB Next Talk: 2018 Opener – David Henderson, MD OSGB Fri 26th Jan]
On Friday 17th November we were delighted to welcome Dr. Lauren Biermann, Senior Satellite Scientist at the Centre for Environment, Fisheries and Aquaculture Science (Cefas), for the second in this series of EEO-AGI Scotland seminars, held jointly with the University of Edinburgh’s Hutton Club. Lauren gave us a very engaging seminar entitled ‘Building Bridges to Satellites: how the UK Government is encouraging uptake of remotely sensed data’, in which she talked about her roles as data scientist at Cefas, Marine Lead at Defra’s Earth Observation Centre of Excellence (EO CoE), and Marine Liaison for UK-GEOS, a cross-government Earth Observation service.
The talk started with a brief introduction to EO, and the benefits and limitations of satellite data for marine science. An obvious limitation is that the vertical complexity of the oceans is hidden from satellites, which can only measure the surface layer. Satellite data also suffer from reduced accuracy in more complex waters (including those around the UK), though this problem is beginning to be addressed by improved algorithms.
The benefit of EO that Lauren emphasised was one that I had not thought about before, but seemed obvious when it was pointed out: its ability to tie together observations at different spatial scales, from local to global. She gave the example of coastal water quality: this could be affected by very local processes; by more regional processes such as river runoff; by pollutants being carried onshore by ocean currents; by large-scale oscillations such as El Niño; right up to global climate change. Marine scientists study these processes using in situ measurements and computer modelling, and the satellite data is what ties together these different observations and spatial scales. This is perhaps especially true now that high-resolution satellite imagery is becoming more available, as this allows smaller-scale phenomena to be studied from satellite data. A beautiful example of this was shown in this talk: a Sentinel-2 image of a Black Sea algal bloom, with a single vessel and its wake clearly visible.
Lauren then presented one of the projects that she worked on with Cefas: Tracking North East Atlantic Mackerel with Earth Observation Data (aka Finding NEAM-EO – an acronym of which she can be proud!). This project started some time ago, looking at how EO data could be used to predict mackerel distribution in the North Sea, but was then picked up by policymakers in the run-up to the Brexit vote because of the so-called ‘Mackerel Wars’ . This dispute pitted Britain, Norway and the EU on one side against Iceland and the Faroe Islands on the other. Although it has now been resolved, the situation could become more complicated once Britain leaves the EU. In disputes of this kind, it is vital to know exactly where the fish are: the argument that Iceland and the Faroes put forward for unilaterally increasing their quotas was that mackerel had shifted their range northwards.
In the North Sea, the Finding NEAM-EO project had used in situ data on mackerel distribution taken from acoustic surveys, and related this to variables that could be measured from satellites, such as sea surface temperature (SST) and chlorophyll concentration. The results showed that SST was a very good predictor of mackerel distribution, along with bathymetry.
Cefas were then asked to extend the project to the North East Atlantic, but there was no in situ acoustic data available to validate the predictions made from the EO data. However, it was possible to track the mackerel trawlers, which are required by law to carry Automatic Identification System (AIS) transceivers. Mackerel could be assumed to have been present wherever mackerel ships slowed down to trawl. This idea was adapted from Dr. Biermann’s PhD work, in which she investigated the foraging behaviour of tagged elephant seals in the Southern Ocean. In the North Sea, the hotspots identified from the AIS data agreed well with the acoustic data, showing that this was a valid method for tracking mackerel distribution. In the Atlantic, the hotspots showed the same strong relationship with SST and bathymetry as in the North Sea.
After giving us this great example of how satellite data can be used to inform policy, Lauren turned to her role as Marine Lead at Defra’s EO CoE, which involves convincing UK Government to integrate satellite data into monitoring and policymaking. There was initially some scepticism among senior civil servants about the value of satellite data, perhaps because of a lack of information about the range of satellite products available. Although Defra have become more engaged with EO over the last few years, there are still barriers to its uptake. Satellite data are big and require specialist knowledge and software to analyse, so the main task of the EO CoE is to make the data more accessible and easier to use for policymakers across government.
The first step was to understand which data government agencies needed to do their work effectively. Some of this data, such as NDVI/crop maps, SST and chlorophyll-a, could easily be made available in an accessible form. Other data products are currently in development, and Lauren spent some time talking about her role in each of these.
Firstly, AIS and radar maps are being developed in collaboration with Cranfield University to help government agencies understand the shipping pressures on UK waters. By overlaying radar images taken at different times, areas of high shipping intensity can be identified. Combining the radar data with AIS data could potentially allow automatic classification of vessels into different types (fishing vessels, recreational vessels, etc.). This is important in helping to police Marine Protected Areas (MPAs) – particularly in the Overseas Territories, where the UK’s main MPAs are. The aim is not so much to catch individuals as to understand patterns so that limited resources can be allocated more effectively.
Secondly, Cefas and Plymouth Marine Labs are working to develop the first product from Sentinel-3 data: 300 m resolution maps of suspended particulate matter, which will help to understand changes in turbidity in the North Sea as well as UK coastal waters.
Finally, Lauren talked about a project she worked on for UK-GEOS, which was set up to promote the integrated delivery of EO products across government departments. This project investigated the use of satellite imagery to identify river runoff plumes, and predict the types of pollutant they might contain based on the industrial or agricultural facilities that were upstream. This is very relevant for understanding the causes of fish diseases, and for improving the sustainability of aquaculture. Consumption of farmed fish surpassed that of wild-caught fish for the first time last year, so this is of vital importance to the sustainability and security of our food supply.
After making a good case for the integration of satellite data with policy and giving us many fascinating examples, Dr. Biermann ended her talk with some more general remarks about the importance of sea literacy – not just among scientists and policymakers, but in society as a whole – and of greater collaboration both within government and between government and academia. The future health of our seas and coastlines may depend on it, and I’m sure that some of those present in the audience will want to be involved.
Daniel Stow (MSc Earth Observation & Geoinformation Management)