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Open satellite data

A wide variety of environmental measurements can now be made from space by satellites. Watch Dr Debbie Clifford explain more.
So there’s an old saying, which is climate is what you expect and weather is what you get. So the climate is really just the average of weather over a long period of time. And climate will tell you whether you expect it to be hotter today in the UK or in Australia. But because of variations in the weather, you may not always get what you expect. It’s really important that we understand our climate and how it is changing, and whether we are having an impact on that, and what we can do about it. But climate also has an impact on a lot of our day-to-day activities, like what crops we should plant, particularly long-lived crops like olives and trees.
And where are we going to get our water resources from, whether glaciers are melting, and whether we expect patterns of rainfall to change? So now if we can start to stitch together the measurements made over all those decades, we can get an understanding of that real climate variability, rather than just the day-to-day variations of the weather. So we can really monitor on a global scale how our climate is changing and varying. There are many scientists around the world using these satellite data to understand how our climate is changing and to monitor things such as water resources and agriculture.
Climate data from space can be really variable, from inventory measurements of glacier sizes, which can be very small data sets in the end, to 30-year record of chlorophyll in the ocean, which will be many, many terabytes, and obviously very difficult to process using just a laptop. Many climate data sets from space are released as open data. The European Space Agency has a programme called the Climate Change Initiative which is constructing these very long-term, very high-quality climate data records using its Earth Observation measurement. And all those data sets are released as free and open data. And the same is true of NASA’s climate data record programme. All that data is released openly.
But sometimes these data sets are so big and so complex that even if they are free and open to use, they can still be quite technical, and specialised to really understand, and to extract the most information from. I think the key thing about using Earth Observation data for climate studies is that you need to be looking at data over a long time period. For climate we’re typically talking many decades, maybe 30 or 40 years. And so if you’re looking at global data over that amount of time, those are really, really big data sets. And you need specialist infrastructure and computing to really extract that information rigorously. So that’s probably the biggest barrier to using these datasets for many applications.
So there are a lot of people, researchers and scientists, around the world who are turning the measurements from Earth Observation into time series or smaller, more digestible datasets for everyone to use in their applications. So many of the measurements that are relevant for climate studies have been made by kind of short-term research missions. So a satellite might only have a lifetime of three to five years. But in the last few years, the European Space Agency has launched the Sentinel series of satellites, which are committing to making these measurements over a long time. So they will keep flying new replacement satellites to make sure we have a consistency of record for these really important measurements.
Watch Dr Debbie Clifford explain how open data from satellites, which monitor the Earth, can help us to understand the effect we’re having on our climate.
A wide variety of environmental measurements can now be made from space. Many observational records stretch back decades, allowing us not only to assess current conditions, but also to detect and monitor changes in the environment over time. This long-term view of environmental variability is what we call ‘climate’, and a climate data record is one that is of sufficient quality that recent and past values can be compared.
Earth Observation scientists around the world are developing climate data records to get the historical consistency needed for their climate science. These climate data are, because of their high quality, potentially valuable to a much wider pool of users than just the scientists interested in monitoring climate change. For instance, the European Space Agency’s (ESA) Climate Change Initiative, is developing global records of climate variables such as clouds, ice sheets, land cover and soil moisture, and releasing them as open data.
In the video, Debbie highlighted the European Space Agency’s open data portal for the Climate Change Initiative, which serves all the key datasets from the programme, and has almost 100TB of data products available. A large proportion of this is the Ocean Colour data set – these data help us understand the important biological role of the oceans in the Earth’s climate, quantifying the amount of chlorophyll and monitoring the uptake of CO2. These free and open datasets are particularly relevant to those interested in: atmospheric aerosols, cloud, fire, greenhouse gases, glaciers, ice sheets, land cover, ocean colour, the ozone, sea ice, sea level, sea surface temperature, and soil moisture.
You can explore these datasets on the Climate Change Initiative open data portal on the ESA website. The portal can be accessed by clicking on “Data” in the left hand menu.
What do you think is the biggest challenge with using climate data from space? Share your thoughts in the discussion area below.
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Big Data and the Environment

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