Atmospheric Emitted Radiance Interferometer. Part I: Instrument Design

TLDR

A ground‑based Fourier transform spectrometer, the Atmospheric Emitted Radiance Interferometer (AERI), was developed by UW‑SSEC for the DOE ARM Program to measure the earth’s surface downwelling infrared radiance spectrum with high absolute accuracy. The paper focuses on the key design features of the AERI that enable it to meet ARM Program requirements for radiometric and spectral calibration, noise performance, and operational reliability. The instrument employs a Fourier transform spectrometer with a highly accurate radiometric calibration system, autonomous controller, extensive data acquisition for monitoring calibration temperatures and instrument health, and real‑time data processing to achieve high‑accuracy downwelling infrared radiance measurements.

Abstract

Abstract A ground-based Fourier transform spectrometer has been developed to measure the atmospheric downwelling infrared radiance spectrum at the earth's surface with high absolute accuracy. The Atmospheric Emitted Radiance Interferometer (AERI) instrument was designed and fabricated by the University of Wisconsin Space Science and Engineering Center (UW-SSEC) for the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program. This paper emphasizes the key features of the UW-SSEC instrument design that contribute to meeting the AERI instrument requirements for the ARM Program. These features include a highly accurate radiometric calibration system, an instrument controller that provides continuous and autonomous operation, an extensive data acquisition system for monitoring calibration temperatures and instrument health, and a real-time data processing system. In particular, focus is placed on design issues crucial to meeting the ARM requirements for radiometric calibration, spectral calibration, noise performance, and operational reliability. The detailed performance characteristics of the AERI instruments built for the ARM Program are described in a companion paper.