Although most people Environmental engineer Annmarie Eldering may be attracted by the always clear sky, the nearby ocean, or the mountains hugging the Los Angeles Basin. Environmental engineer Annmarie Eldering is attracted by the city’s smog. “This is the best place to go,” she said. “You have tons of pollution!”

More than 70% of man-made carbon dioxide emissions are released in urban areas, and these carbon dioxide will eventually enter the atmosphere, and Los Angeles is no exception.Los Angeles has more than 13 million residents in its larger metropolitan area, well-developed highway network and international transportation hub, and its carbon dioxide emissions rank fifth2 All cities in the world. This makes it the best place to study the role humans play in climate change.

Eldering is a project scientist at NASA Orbital Carbon Observatory 3 or OCO-3, which is an instrument for measuring atmospheric carbon dioxide2 To better understand the impact of human activities on the natural carbon cycle, the natural carbon cycle is a process in which plants, soil, ocean and atmosphere exchange carbon with each a Papers published this month, Eldering and her colleagues released a map showing the most detailed changes in CO2 Emissions over the Los Angeles Basin as seen from space. This study shows that space-based monitors can be used to collect a large amount of pollution hotspot data, which can help formulate policies to deal with climate change.

“The exciting result of OCO-3 is that this is the first time we have obtained this kind of regional map of a city like Los Angeles from space,” said Joshua Laughner, a postdoctoral scholar at the California Institute of Technology who works on a global scale. The monitoring-based system is called Total Carbon Column Observation NetworkAlthough instruments such as TCCON can be used to accurately observe changes in atmospheric carbon concentration over time, they are expensive to operate and require cooperation with skilled scientists, so their data collection is limited to specific areas. In contrast, the orbiting observatory can scan parts of the earth that are difficult to study from the ground, such as volcanoes or cities with high carbon footprints but few monitoring resources.

OCO-3 was launched in 2019 and is now installed on the International Space Station. According to a report, it can see almost every city on Earth in an average of three days NASA press releaseThis is an improvement to its still active predecessor, OCO-2. OCO-2 can only collect data up to 10 kilometers wide and is locked on the sun-synchronous orbit passing through Los Angeles at the same time every day, which means it can only check Atmospheric carbon dioxide in cities2 1:30 pm.

“Using OCO-3, we have better spatial and temporal coverage because it can now observe the city at different times,” said Dien Wu, a postdoctoral scholar at the California Institute of Technology who worked closely with the team to analyze urban emissions. OCO-3 can scan a location multiple times and draw a snapshot of approximately 80 square kilometers in just two minutes.

The color of each pixel This map was created by Eldering’s team Represents atmospheric CO2 Concentration in a ground area approximately 1.3 miles wide. Because carbon dioxide absorbs certain wavelengths of light, scientists can use this information to infer how much carbon dioxide is in the earth’s atmosphere. OCO-3 observes the change in the intensity of sunlight as it passes through a vertical air column and a reading of how much carbon dioxide it produces2 In that place.

The OCO-3 team then compared these satellite data with the “clean air” readings already collected by NASA’s Armstrong Flight Research Center’s ground-based TCCON instrument, which is located in the desert north of Los Angeles, far away from local emission sources. Use about 410 ppm (or 410 CO2 Per million molecules of dry air), OCO-3 can recognize differences as low as five parts per million.They see a peak excess of carbon dioxide2 More than five parts per million in the Los Angeles Basin. This may sound small, but it is equal to the global increase in these emissions every two years.

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