Coronavirus and Water Quality🦠 — what’s the correlation?

A simple way to map and plot water quality using an open and free tool provided by NASA, JAXA and ESA

During lockdown periods, the major industrial sources of pollution affecting aquatic ecosystems (such as industrial wastewater, crude oil, heavy metals, and plastics) decreased or completely stopped, resulting in reduced levels of pollution — and this can be observed from Space using satellite data. In an unique unprecedented collaboration, three space agencies - NASA, JAXA and ESA are making it possible to access this information through a user-friendly tool, available at the touch of a finger, free and open to all.

This tri-agency effort resulted in the “eodashboard” — COVID-19 Earth observation dashboard which allows to understand the effects of the pandemic on water quality, as well many other environmental variables, as consequence of human activity changes.

eodashboard.org — The dashboard developed by the three space agencies offers the possibility to track changes in air, climate change, economic activity and agriculture, through the integration of multiple satellite data provided by NASA, JAXA and ESA.

At the same time, ESA and the European Commission, developed the twin platform, “RACE” — Rapid Action coronavirus and Earth observation. Both platforms are similar, as the overarching goal is to understand the impacts on societal and economic changes driven by the coronavirus pandemic. The main differences between both platforms are the level of detail, regions covered and satellite data. We will go through them in the instructions below to generate water quality maps and water quality time series.

race.esa.int — The online platform resulting from ESA and European Commission provides a deeper insight across different indicators in European countries with data from Copernicus constellation.

Generating water quality maps

No registration or software is necessary. You just need to access the tools through their websites. Open eodashboard.org and select ‘Water Quality Maps’ (on the left side of the panel) and zoom in on San Francisco, USA for example. On the map itself you can click on one of the two droplet icons 💧 — that will generate Chlorophyll-a and Total Suspended Matter anomaly maps (in %).

To inspect the map you can enlarge it (clicking on the arrows icon in the top left corner of the map generation panel). You can also compare different dates changing the dates below. In this example below, the values of chlorophyll-a (Chl-a) are generated by USGS/NASA Landsat 8 and ESA Copernicus Sentinel-2 satellites and we are comparing a date prior to lockdown with another date while lockdown measures were into place. The decrease of chl-a concentrations (which is itself an indicator of water nutrient levels and algae growth) may indicate some link between decreased activities resulting from the shelter-in-place order, as the nutrient inputs of anthropogenic origin (e.g. sewage discharge, industrial runoff and fertilizers) might have decreased. However, further research would be required to explore any linkages between human activities and natural climate variability in the region.

Chl-a anomaly (%) in San Francisco before (2020/03/02) and during lockdown periods (2020/04/03)

On some locations, like in the case of the North Adriatic, the map will load data coming from more than one single satellite. For example, if you go explore Venice lagoon (where Covid-19 outbreak brought tourism to a screeching halt leading to a decrease of Chl-a as result of decrease of maritime traffic) the map will load satellite data provided from three different satellites, allowing for a denser observation by combining the views from the 3 agencies.

Likewise, in other regions of the globe you might find similar results or have other findings when generating total suspended matter maps (as this variable shows a more direct influence of the suspended-matter upwelling). As mentioned before, the data of the maps generated for each location will depend on their location - for example Rhone delta water quality maps have data provided by ESA (Copernicus Sentinel-3) and Tokyo maps are provided by JAXA (GCOM-C satellite).

Several datasets available for different locations: (LEFT) Rhone delta — Total suspended matter anomaly (%) (RIGHT) Tokyo Bay — Total suspended matter anomaly (%)

Generating Time Series

For water quality time series the approach is the same. Open now the race.esa.int platform. Select the ‘Water Quality Time series’ indicator and choose a location — in the example below we show Barcelona, Spain. On the right panel a graph containing Chl-a concentration values over time will be generated automatically. As show in the GIF , you can select the period by zooming in or out with the mouse over the graph.

race.esa.int

The graph allows to compare the concentration of Chl-a during 2020 with the average values over the 2017–2019 period. RACE also generates a visual indicator, (a blue, green and red circles for high, normal or low concentration, respectively) which indicate the status of Chl- a concentration values in respect to reference values. In the case of this location there is the striking notion of improved water quality over the period of high restrictions (marked with a red background).

Explore and share with the world!

We invite you to explore these tools. If you find interesting results we would like to hear from you. Share on Twitter, tag @EO_OPEN_SCIENCE account and with #EOCOVID19.

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