Pressure, temperature, and ozone profile retrieval from simulated atmospheric earthlimb infrared emission

A method is presented for retrieving pressure, temperature, and ozone mixing ratio profiles from multilevel high resolution earthlimb emission data taken in the spectral region near the CO(2)Q-branch at 791.5 cm(-1). Theory is developed for the construction of a retrieval algorithm which brings the magnitudes of calculated and measured CO(2) and O(3) features into agreement by adjusting a hydrostatic trial atmosphere having one fixed reference pressure. It is shown that overlap between the CO(2) and O(3) features can be used to determine the correct reference pressure. The method is examined using simulations to demonstrate the retrieval of vertical profiles of pressure, temperature, and ozone mixing ratio in the stratosphere. Numerical studies of the effects of uncertainties in line parameters and instrument calibration errors are also presented.

Cryogenic Fourier spectrometer for measuring trace species in the lower stratosphere

A cryogenic Fourier transform spectrometer has been built to measure thermal emission of the earth's limb from a balloon-borne platform. Liquid nitrogen cooling of the spectrometer and liquid helium cooling of the detectors has provided sufficient sensitivity to detect, at 5-15 microm, fifteen molecular species relevant to stratospheric ozone chemistry. The spectral resolution achieved, 0.022 cm(-1), is the best yet attained for emission mode data at these wavelengths. The philosophy behind the design of the optical and electronic systems is presented, followed by an analysis of the performance achieved during balloon flight.

Retrieval of constituent mixing ratios from limb thermal emission spectra

An onion-peeling iterative, least-squares relaxation method to retrieve mixing ratio profiles from limb thermal emission spectra is presented. The method has been tested on synthetic data, containing various amounts of added random noise for O(3), HNO(3), and N(2)O. The retrieval method is used to obtain O(3) and HNO(3) mixing ratio profiles from high-resolution thermal emission spectra. Results of the retrievals compare favorably with those obtained by others.