The European Space Agency launched an instrument three years ago called the TROPOspheric Monitoring Instrument (TROPOMI) that can measure the methane in any 12-square-mile block of the atmosphere, day by day.
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Lauvaux says that TROPOMI detected methane releases that the official estimates did not foresee. "No one expects that pipelines are sometimes wide open, pouring gas into the atmosphere," he says.
Yet they were. Over the course of two years, during 2019 and 2020, the researchers counted more than 1,800 large bursts of methane, often releasing several tons of methane per hour. Lauvaux and his colleagues published their findings this week in the journal Science.
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The researchers consulted with gas companies, trying to understand the source of these "ultra-emitting events." They found that some releases resulted from accidents. More often, though, they were deliberate. Gas companies simply vented gas from pipelines or other equipment before carrying out repairs or maintenance operations.
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The countries where bursts of methane happened most frequently included the former Soviet republic of Turkmenistan, Russia, the United States, Iran, Kazakhstan and Algeria. Lauvaux says they found relatively few such releases in some other countries with big gas industries, such as Saudi Arabia.
Might feel like a stupid question but how is a satellite that is revolving at several thousands of meters above the earth's surface be able to detect a gaseous substance like methane living near...
Might feel like a stupid question but how is a satellite that is revolving at several thousands of meters above the earth's surface be able to detect a gaseous substance like methane living near the earth's surface? Are there any kind of sensors that detect methane in the air and tell that to the satellite's software (the way fire alarms work)?
To give a bit of an ELI5 explanation, imagine looking at the sunlight via a prism: Make a dark chamber, split the sunlight into a rainbow, look at it. Measure the intensity of light for every...
To give a bit of an ELI5 explanation, imagine looking at the sunlight via a prism: Make a dark chamber, split the sunlight into a rainbow, look at it. Measure the intensity of light for every color. Also look at the parts "above" and "below" the rainbow, i.e. IR and UV light. Alright, good. What you get there is the spectrum of emitted light from whatever source you're looking at.
What's going on is that certain compounds radiate certain frequencies. A red-hot glowing piece of metal will probably put out a smooth distribution. But for example electrically excited sodium metal will output a very strong signal somewhere in the orange-yellow area. If you've ever seen yellow street lamps, that's likely sodium metal. The light is yellow but gives you basically no color vision because there's basically no different colors present in the light it gives off. Point a good camera that looks at different wavelengths at the earth, and you could for example find out every place where sodium metal lamps are being used: Everywhere where that wavelength is overrepresented compared to the rest of the spectrum.
Now, what about methane? Well, the same situation applies: Excited methane will emit certain wavelengths. Find those wavelengths, compare to the expected background, see methane. They might (and TemulentTeatotaler's comment suggests as much, but I can't tell for sure) also go a different route and look at what wavelengths get absorbed. Each compound absorbs different wavelengths, so if those wavelengths are missing compared to what could be expected, that's because methane is absorbing them. This is also how the molecules get excited to begin with, absent a power source like in the street lamp: Absorb photon A, emit photon B. You ever played around with blacklight UV lamps? Some things convert the UV light to visible light. Same principle. So if photon A is missing, or photon B is present, you can measure it.
All of those techniques are likely to be super complicated in practice because the data you get is likely super messy, so it takes a lot of tinkering and collecting control data before this actually works for real.
Here is the instrument's page: A lot of information is carried in how something interacts with certain frequencies of electromagnetic radiation, which I think is mostly what they're using. With...
TROPOMI uses absorption information from the Oxygen-A Band (760nm) and the SWIR spectral range to monitor CH4 abundances in the Earth’s atmosphere. Data from the GOSAT satellite instrument and ground-based TCCON instruments are used for verification and validation. With the most recent algortihm update, methane which was previously a land-only data product, now includes pixels with sun glint over parts of the ocean.
A lot of information is carried in how something interacts with certain frequencies of electromagnetic radiation, which I think is mostly what they're using. With some processing to clean it up and more accurate follow up done on site if it's called for.
From the article:
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Might feel like a stupid question but how is a satellite that is revolving at several thousands of meters above the earth's surface be able to detect a gaseous substance like methane living near the earth's surface? Are there any kind of sensors that detect methane in the air and tell that to the satellite's software (the way fire alarms work)?
To give a bit of an ELI5 explanation, imagine looking at the sunlight via a prism: Make a dark chamber, split the sunlight into a rainbow, look at it. Measure the intensity of light for every color. Also look at the parts "above" and "below" the rainbow, i.e. IR and UV light. Alright, good. What you get there is the spectrum of emitted light from whatever source you're looking at.
What's going on is that certain compounds radiate certain frequencies. A red-hot glowing piece of metal will probably put out a smooth distribution. But for example electrically excited sodium metal will output a very strong signal somewhere in the orange-yellow area. If you've ever seen yellow street lamps, that's likely sodium metal. The light is yellow but gives you basically no color vision because there's basically no different colors present in the light it gives off. Point a good camera that looks at different wavelengths at the earth, and you could for example find out every place where sodium metal lamps are being used: Everywhere where that wavelength is overrepresented compared to the rest of the spectrum.
Now, what about methane? Well, the same situation applies: Excited methane will emit certain wavelengths. Find those wavelengths, compare to the expected background, see methane. They might (and TemulentTeatotaler's comment suggests as much, but I can't tell for sure) also go a different route and look at what wavelengths get absorbed. Each compound absorbs different wavelengths, so if those wavelengths are missing compared to what could be expected, that's because methane is absorbing them. This is also how the molecules get excited to begin with, absent a power source like in the street lamp: Absorb photon A, emit photon B. You ever played around with blacklight UV lamps? Some things convert the UV light to visible light. Same principle. So if photon A is missing, or photon B is present, you can measure it.
All of those techniques are likely to be super complicated in practice because the data you get is likely super messy, so it takes a lot of tinkering and collecting control data before this actually works for real.
Here is the instrument's page:
A lot of information is carried in how something interacts with certain frequencies of electromagnetic radiation, which I think is mostly what they're using. With some processing to clean it up and more accurate follow up done on site if it's called for.