An infrared sensor instrument aboard NASA's Aura Earth satellite, the Tropospheric Emission Spectrometer, or TES, is designed to measure and investigate Earth's troposphere, the lowest level of Earth's atmosphere, and one of its key chemical components, ozone. In 2010, scientists devised a way to use data from the instrument to also study carbon dioxide levels across the globe.

The Tropospheric Emission Spectrometer is part of a fleet of NASA instruments and spacecraft studying global climate change issues as part of the agency's Earth Observing System.