NASA has announced plans to launch the first satellite that will monitor levels of carbon dioxide in the atmosphere around Earth. The Orbiting Carbon Observatory-2 (OCO-2) mission, which cost $465 million, will be launched on July 1, from Vandenberg AFB in California. The satellite will probide an improved picture of the natural and human sources of global carbon dioxide. The mission will also identify sinks into which the carbon dioxide is being absorbed. This particular satellite is a replacement for one that was lost during a launch in 2009.
The oceans and plants on the planet absorb approximately 50 percent of the almost 40 billion tons of the greenhouse gas that is added to the atmosphere annually by fossil fuel burns and various other activities. A scientist on the project, Mike Gunson, made the point that even though emissions of carbon dioxide steadily increase, the surface sink absorption tends to vary depending on the year.
He goes on to say that a deeper understanding of why the changes occur will aid scientists in the reduction of uncertainty when it comes to global projections of climate change. Just how much of the greenhouse gas goes into the atmosphere, Gunson says, is a huge uncertainty.
An OCO-2 mission executive, Betsy Edwards, believes that the timing could not be better for this mission. It lines right up with President Obama’s climate action plan and steps that have recently been taken in the reduction of carbon emissions. She said that the data provided will aid decision makers, both federal and local, by improving their understanding of the role carbon dioxide plays in climate change.
The instrument on the satellite used for sampling will do its job for two years, taking dense samples every 16 days. Edwards said that this will impart an unprecedented account of global atmospheric carbon dioxide with a high level of resolution and coverage. The goal for NASA is to make measurements of the concentration of atmospheric carbon dioxide with a one part per million sensitivity.
It is likely that the measurements the satellite takes will be combined with other source data. For instance, Japan is monitoring methane and carbon dioxide concentrations using their Greenhouse Gases Observing Satellite. The National Oceanic and Atmospheric Administration (NOAA) has a ground-based system of observation that has been taking measurements of atmospheric carbon dioxide since the 1950’s. NASA’s findings will be confirmed against NOAA’s measurements.
The director of global monitoring for NOAA’s Boulder, Colorado Earth System Research Laboratory is Jim Butler. He said that their ground-based system of observation is the most reliable in the world for global carbon dioxide emissions trends. Butler points out that even when NOAA’s 70 sites are combined with those operated by the World Meteorological Organization, there are only 150 worldwide sites taking these types of measurements. When taking into consideration the size of the planet, that is not very many. Butler continued, saying the satellite will fill in gaps by targeting emissions on a fine, granular scale, which will be very helpful.
A couple of drawbacks are that oceans and clouds create difficulties for satellites. To help with the cloud issue, the satellite will be able to scan a square mile at one time. NASA’s carbon dioxide monitoring satellite will have two modes of operation once it is launched. The first mode will have the instrument pointed down toward the Earth. In the second mode, the instrument will be pointed close to the reflection of the sun on the Earth. This will help in getting more accurate measurements when the satellite is over oceans.
By Stacy Lamy