CO2 | OCO-2 Joins The A-Train

Update Dec.19 2014

The first image was released showing the carbon dioxide levels measured by OCO-2. High values are in orange and red. Much of that appears from burning of biomass according to this release from NASA.


Original Post

The Orbiting Carbon Observatory-2 was launched early July 2, 2014. This night-time long exposure from Vandenberg Air Force Base in California is interesting. Its mission is to monitor the carbon dioxide (CO2) in the atmosphere to better understand the sources of it and where it goes. The greenhouse gas is part of a natural carbon cycle that is depicted in the graphic below. The sources of CO2 from human activity has increased steadily. Levels in the atmosphere are at an all time high of >400 ppm and rising. The OCO-2 spacecraft will help us understand and plan more effective measures to deal with this problem in the future.

U.S. DOE | Biological and Environmental Research Info Sys | Yellow = natural fluxes. Red = human contributions. White = stored carbon. Quantities in billions of tons of carbon per year.

The Carbon Cycle

Carbon is found naturally is five main reservoirs. They include the atmosphere, the biosphere of surface plants and animals, dead and alive, along with the soil, the oceans, the sediments of the oceans, and lastly the mantle and crust of Earth. These natural reservoirs don’t include human influences. Carbon is exchanged between the oceans, sediments, atmosphere, and biosphere in natural processes that maintained a steady state balance over the eons of time. Since humans have been burning large amounts of fossil fuels, that has resulted in a buildup of carbon in the atmosphere. It is unable to be transported to other reservoirs. As a result, the atmosphere is trapping heat from the Sun and raising the temperatures world wide. We are seeing the phenomenon of global warming and resulting changes in climate patterns.

The Spacecraft


The Instrument

The field of view of the OCO-2 instrument is about the size of Central Park in New York City, or 3 square kilometers. The view needs to be small in order to avoid clouds in the view. They compromise the data returns. The best carbon dioxide observations via satellite now take 4 seconds to make one reading. That is fewer than 20,000 pieces of data per day. Only about 500 of those are highly useful. OCO-2 will collect 24 readings every second for about 1 million a day. About 100,000 of those will be highly useful.

The A-Train Group

The OCA-2 spacecraft joins a group called a satellite constellation. This constellation is called the Afternoon Train, or A-Train. They follow one another in polar orbit passing over the same locations within seconds of each other. Their nearly simultaneous data collection assures that atmospheric conditions have not changed for the ensemble of data. Their altitude and grouping allows for an equator crossing at about 1:30 pm each day and 1:30 am each night in addition to their others about 90 minutes apart.


The Mission

The two year mission, which could be extended, will yield much valuable information about the CO2 sources and sinks around the world. Accuracy will be increased by about 10x. Currently, the globe has about 100 monitoring stations for CO2. Many areas have none. This spacecraft will have global coverage in high resolution.

Models will be improved describing the carbon content and transport around the world. These improvements will allow scientists to make better forecasts and predictions about global climate change.


17 thoughts on “CO2 | OCO-2 Joins The A-Train

  1. What a great tool for the planet! Thanks for breaking this down. I heard they pulled off the launch through a narrow window, despite hurricane Arthur but didn’t understand how the collection process worked.

    • There was a 30 sec launch window. It had to go up as the rest of the A-train of satellites came by. Otherwise, it would not be inserted into the train group.

      The launch was from California.

      • I meant to finish that launch thought earlier. But, my iPad wouldn’t let me continue typing. So here is the rest.

        The A-train is in an orbit that passes over the poles. Launch to that orbit requires a clear uninhabited path to the north or the south. Florida is only clear to the east. The CA site allows launches to the south.

        At first, I assumed a FL launch until I read more of the press releases that explained it.

    • Sadly, you are probably right. Most humans don’t plan ahead wisely. I’m not ready to give up on science and knowing how nature works as it kills us off.

      Who knows? We might find some useful info for surviving generations to use.

      Thanks for your cartoon. Gave me a chuckle.

  2. When I was commuting to college I sometimes used to ride the A-Train (subway) in Manhattan, but I think I’d much prefer the view from this A-Train, even as I’m pretty sure I couldn’t afford the fare.

    • It has not received much attention. An almost identical spacecraft failed to get into orbit in 2009. Maybe they wanted to do this one quietly just as a precaution.

      Thanks for your visit.

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