Far-infrared spectroscopy of the troposphere - FIRST

A new and unique tool for remote sensing of the atmosphere has been developed and demonstrated on a high-altitude balloon platform. The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Michelson FTS that covers the spectral range from 50 to 2000 cm-1 at a nominal spectral resolution of 0.625 cm-1. It is the only extant instrument capable of measuring the entire infrared spectrum of the Earth and its atmosphere. In this talk we review the FIRST instrument and the results of its demonstration flight from June 2005. We also discuss the future potential of the present instrument for both ground-based and balloon flight observations. Technical challenges associated with the development of a space-based far-infrared instrument and concepts for such a sensor are presented. Far-IR measurements enable direct determination of the primary atmospheric cooling rates, cirrus cloud properties, understanding of the basic water vapor greenhouse effect, and water vapor feedbacks in the upper troposphere.