When a team from NASA's Langley Research Center wanted to study water vapor in the atmosphere, they decided to go to one of the driest places on Earth. From a mobile lab on a mountain-top in Chile's Atacama Desert, the Langley-led team has spent months observing water vapor's effect on the climate. The remote and dry location allows for better scientific observations.

Using a new instrument called Far-Infrared Spectroscopy of the Troposphere (FIRST), the team is taking measurements of water vapor emissions in the "far infrared." This part of the spectrum has rarely been measured from the ground, and has never been measured thoroughly from space, though it is thought to account for half of the Earth's cooling emissions to space. The FIRST campaign in Chile, from August to October, will help Langley scientists and engineers better understand how water vapor controls the climate and energy balance of the planet. FIRST is also a prototype for an instrument that would eventually fly on the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission, which would be the first to measure the full infrared spectrum from space.