New design of a Multi-Order Etalon Sounder for measuring stratospheric temperature profiles

摘要

Abstract: Sounding the stratosphere using the 4.3 $mu@m CO$-2$/ lines requires observations where radiance contributions from the very thin upper atmosphere form a significant part of the measured signal. In order to properly account for the influence of these extremely narrow emission features in the temperature retrievals, extremely high spectral resolution is required. The multi-order etalon sounder (MOES) is an instrument which capitalizes on the extremely high spectral resolution achievable with a standard Fabry-Perot etalon and on the regular spacing of the lines in portions of the vibration-rotation spectrum of gases such as CO$-2$/. The MOES instrument simultaneously measures several identically shaped CO$-2$/ lines when its etalon spacing is set to produce a free spectral range equal to the uniform line intervals in the spectrum. By combining the signals from a large number of lines a MOES sensor greatly improves the signal-to-noise ratio without reducing its inherent spectral resolution. A detailed design for the most recent MOES concept is presented along with its expected/simulated performance parameters. !5