Friday, June 13, 2014

NASA's Carbon Observatory

On February 24, 2009 NASA launched a satellite that would have been a major resource in climate change research - the Orbiting Carbon Observatory (OCO). Unfortunately, the protective launch fairing covering the satellite failed to separate as required and the extra weight prevented the satellite from reaching orbit. We can only speculate at this time what kind of data we would have been able to measure in the five years since then. We haven't been completely without data, though. The Japaneses satellite GOSAT has been providing us with some of the missing data since 2009.

The good news is that the Orbiting Carbon Observatory-2 (OCO-2) is set to launch July 1 from Vandenberg AFB in California. Once in orbit, it will be in a constellation of five satellites that measure Earth's environment. The orbit of these satellites is 99 minutes long and pass over the equator (going north) at 1:36 PM local solar time. That means when they are directly over the equator, the point on the Earth's surface directly beneath them will always have the Sun at the same point in the sky. The advantage to this is that all of the measurements will be nearly simultaneous and will be made at about the same local time. This makes it possible to compare data taken many orbits apart and not have to worry about variations due to changes in the solar angle.

OCO-2 is a very important mission and the instruments on the satellite will collect data that is critical to our understanding of what is going on with carbon dioxide in our atmosphere. We know that the level of CO2 is rising and we know most of the increase is due to man made activities, but we are lacking in specific details. Where is the CO2 coming from? And, where is it absorbed. In scientific parlance, that is known as sources and sinks. And, how are these sources and sinks changing over time? If something is a sink or source today, but was even more or less of a sink or source years ago, that is important to know. This mission will help us answer questions like that. It will be used in conjunction with data from aircraft, land stations and other satellites to provide a more complete picture of what is going on.

We know that the level of CO2 in the atmosphere is the highest it has been in at least the last 800,000 years. We know man made CO2 is responsible for the rise. We know much of the CO2 is being absorbed by the oceans, causing them to become more acidic. But, where does the rest of the absorbed CO2 go? The specific location and identity of those sinks is not fully understood. Detailed information is needed.

If the launch is successful this time, OCO-2 will begin orbiting Earth and providing thousands of data points on the CO2 cycle and our understanding of what is going on will begin to improve.

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