NASA has updated the algorithms used to process data from two space-based instruments, creating a more precise global record of carbon dioxide (CO2) in Earth’s atmosphere. The dataset combines measurements collected since September 2014 by the Orbiting Carbon Observatory-2 (OCO-2) and OCO-3.
The instruments record more than one million daily observations of sunlight reflected from Earth’s surface. Algorithms use the physics of how light travels through the atmosphere to estimate carbon dioxide concentrations.
OCO-2 launched as an independent satellite in 2014, while OCO-3 was installed on the International Space Station in 2019. Together, the instruments provide global coverage that supports research into the carbon cycle, including how carbon moves between different reservoirs on the planet.
The update improves instrument calibration and the way the calculations account for factors such as atmospheric clouds and aerosols, as well as the way sunlight reflects off the oceans. Following the changes, researchers found that the CO2 estimates were generally closer to highly precise atmospheric measurements collected by a global network of ground-based instruments.
The measurements from OCO-2 and OCO-3 also showed strong agreement with one another, despite the instruments observing Earth from different angles, at different times and along different orbital paths. The resulting record covers the period from September 2014 to the present and was published in the journal Earth and Space Science.
The updated dataset allows researchers to track the rate of atmospheric carbon dioxide accumulation month by month, rather than relying only on annual comparisons. This may help them identify more quickly how events such as wildfires, droughts and El Niño affect the carbon cycle.
The publicly available record can also support studies of carbon behavior at different scales, from cities to the entire planet, and help researchers assess the effectiveness of climate policies.
Sources: Olhar Digital.