14 DAY TRIAL // Not many people think of a satellite constellation when they hear the term A-Train. Yet, this is now proving to be one of the most potent scientific instruments scientists have for analyzing the Earth.
All of the spacecrafts in this group have a single purpose, and that is to allow experts to gain a deeper understanding of how global warming changes the planet's climate as we speak.
The name of the constellation is an abbreviation for Afternoon-Train, given that the satellites pass across the Equator each day at around 1:30 pm local time.
At this point, the group includes the Aqua, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Aura satellites, which fly close in each other's tracks.
They carry a combined total of 15 scientific instruments, which analyze various traits of the atmosphere, oceans, land and soils underneath, providing a comprehensive view of how the planet is changing. They pass over the same area at close intervals, hence the nickname “train.”
The constellation's path is opened by Aqua, which measures temperatures, water vapor amounts and rainfall. It is closely followed by CloudSat and CALIPSO, which measure aerosols and clouds.
CloudSat is a cooperative mission of NASA and the Canadian Space Agency (CSA), and it is capable of “X-raying” clouds to understand how they form, and what type of influence they exert on the climate.
CALIPSO is a collaborative effort between NASA and CNES, the French space agency's Centre National d’Etudes Spatiales. It uses lasers and radars to provide 3D views of airborne particles called aerosols, that play an important role in managing sunlight reaching our planet.
The last satellite in the train is Aura, which produces high-resolution vertical maps of greenhouse gases (GHG) and other particles that can usually be found in the atmosphere.
In the near future, two new satellites will be added to the A-Train. NASA plans to launch the Glory satellite to study aerosol distribution and influences in a lot more detail.
The second spacecraft, called the Orbiting Carbon Observatory 2 (OCO-2), will keep track of Earth's carbon cycle, which is extremely important considering that carbon dioxide is the most common GHG.
“Still, pressing questions about our climate remain. What is the overall affect of aerosols and clouds on climate? How much carbon is absorbed by forests?” NASA says in a press release.
“How will the monsoon cycle react to a warming world? To what extent will a changing climate change the size and strength of hurricanes? And what feedback cycles will encourage or discourage climate change?” the agency ask.
“These and many more questions still need answers, and now that the power of formation flying is clear, it is a good bet that A-Train satellites will play a key role in answering them,” the release concludes.