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Topic 2d – Atmosphere: in-depth case study – monitoring GHGs and aerosols

How do we monitor greenhouse gases and aerosols from Space?
It is extremely important that we monitor CO2, because it is an important greenhouse gas. And satellite data inform us on how to model and represent the CO2. This image is actually based on a model simulation, on a model forecast of the CO2 cycle for September, 2014. And you can see the amazing detail of the cycle of respiration and photosynthesis. The green values are below the ground, and that’s the activity of the plants in late summer producing, actually removing CO2 from the atmosphere and producing oxygen. So you see like it’s below the ground. Whereas the red spots that you see are associated with production of the CO2, and those are associated to wildfires or anthropogenic activity.
And just the cycle of vegetation and when it’s the dry season. Likewise, we have a simulation here of a dust storm from the satellite data. And you can see that the dust produced in the desert by uplifting, by the wind, it’s transported all of the way across Europe. And it affects air quality in most of southern Europe. This image is based on satellite data that are incorporated in the model. They provide initial condition for their model simulation, for the prediction. And then images like this can be realised. And this is actually a prediction into the future, five days ahead. A recent mission that was launched this July is the orbiting Carbon Observatory.
And that’s going to allow scientists to observe the amount of carbon that’s currently in the atmosphere with hundreds of thousands of measurements made every day, and at a global scale. So we can track where those emissions came from by running atmospheric transfer models in reverse. Atmospheric transfer models are what tell you, for example, if I emitted carbon right here, where would it be in two hours? Where would be in two days? Where would be in two weeks? Et cetera. So when we’re able to see where carbon is in the atmosphere from space, we run those models in reverse and we find out where it originated.
And that’s going to help us when we’re trying to estimate how much carbon was emitted by a certain country. So policy considerations require us to have spatially explicit estimates of carbon emissions. And the orbiting Carbon Observatory will allow us to do that. Another variable that we constantly monitor is fire emissions, and this is essential for our prediction system. We can see here images of a fire raging in South Africa and in Spain and Portugal, and these images are amazingly detailed. They show the location of the fires, and also the smoke coming out of these fires. This type of data can really help us have a successful prediction of this type of event.
A great example of that was from 2013, when raging fires were happening in Canada. It’s normal that you have wildfires. However, the type of circulation that year was so strong, was so intense, that the smoke from the fires made all the way across the Atlantic into Europe and were actually observed by ground based sensing lighters, sensinometors. You can see a satellite image of the smoke, and this took– along with other data– for example, data the MODIS satellite, from the Yazi satellite, the CO product, and the data from Mopit as well CO, went into the analysis and produced exactly this type of forecast.
You can really see the details of the plume being affected by the winds all the way from Canada to Europe. And although in this case the smoke stayed at elevated levels between two and six kilometres– so it was not really affecting air quality at the surface, people may have wondered about the hazy quality of the skies, and they may have actually been surprised had they know that the smoke was coming all the way from Canada. And the forecast is based on this product that I mentioned earlier, the fire emissions that are based on the satellite data that we receive daily. In that case, air quality was not affected, because the layer of smoke stayed between two and six kilometres.
But it’s interesting and important to monitor these type of situations, because in a changing climate, they may be more recurring and may end up affecting, perhaps, air quality.
This video will explore how satellite data relating to the composition of Earth’s atmosphere is enabling us to run increasingly detailed atmospheric models, and what this can mean for policy. It also introduces NASA’s Orbiting Carbon Observatory (OCO-II), a satellite that is specifically tailored to provide accurate, global measurements of atmospheric CO2.
Increasing atmospheric concentrations of carbon dioxide (CO2) are the most prominent and well-known driver behind our changing climate. Through heavy industrialisation, humans have released huge amounts of CO2 and other greenhouse gases into the atmosphere, and have also removed some of the areas of forest that help absorb atmospheric CO2 and store it as carbon in vegetation. Over time, these human activities have caused changes in our climate, and whilst these changes may perhaps be almost imperceptible to us personally, measurements with EO sensors and other types of measurement device show significant impacts at both the regional and global scales. By combining these types of data within numerical modelling, we can also make forecasts of what climate changes we might see in future years.
It is highly important that we measure CO2 and other atmospheric constituents having an impact on the climate, so that we can keep track of the evolution of climate change drivers, assess and improve the models we use for forecasting the future, and use the results to build well-informed climate change mitigation and adaptation policies. Such detailed monitoring of our atmosphere also allows for early warning of events that might impact the quality of the air we breathe, for example forest fires or dust storms, whose impacts can be felt far away from the source region.
Satellites provide us with the detailed information necessary to assess the changing concentrations of CO2, other trace gases, and aerosols in our atmosphere. These data allow us to build global maps of the atmospheric concentrations and the sources and sinks of these atmospheric constituents, providing us with the essential information needed to develop and implement climate and environmental policy, assess their effectiveness, and create projections of future conditions. This might be forecasts a few days ahead for early warning of periods of reduced air quality, or decades ahead in relation to what the changing concentrations of atmospheric greenhouse gases might mean for Earth’s climate.
Featured Experts:
  • Dr. Angela Benedetti
  • Dr Kirsten Barrett
Optional Further Reading:
If you want to explore this topic further, please take a look at the ‘See Also’ links below. Click ‘back’ on your browser to return to the course.
Explore the Imagery, Data and Satellites:
You can explore the imagery, data and EO satellite missions from this topic more fully using the links and downloads on the next step.
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Monitoring Climate from Space

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