Earth Explorer 11 Mission Candidate Cairt: Phase 0 System Study and E2E Simulator Overview

The Changing-Atmosphere Infrared Tomography (CAIRT) mission, selected in 2021 as Earth Explorer 11 candidate alongside Seastar, Nitrosat, and WIVERN, has been approved to enter phase A following a public user consultation meeting. With an overarching goal to reveal, resolve, and unravel the complex coupling between composition, circulation, and climate, CAIRT aims to observe atmospheric constituents and processes from the mid-troposphere to the edge of space. This paper provides an overview of the mission concept, emphasizing the mission objectives and requirements, and key design drivers. The CAIRT science objectives encompass atmospheric circulation, gravity waves, coupling with atmospheric regions above and below the middle atmosphere (the thermosphere and the troposphere), as well as a generally improved knowledge of the radiative-dynamic-chemical coupling that governs the Earth’s climate system. The proposed imaging Fourier Transform Spectrometer (FTS) in the thermal infrared is crucial for meeting these objectives.