Abstract

The utility of the onion peel method to invert remotely sensed occultation data is well proven for satellite and balloon borne instruments at a variety of spectral resolutions. The advantages of the onion peel technique include stability in the presence of noise, insensitivity to first guess values, computational speed and relatively simple software coding. A major concern with the onion peel inversion method is the potential for the downward propagation of error into successively lower tangent levels that can be accentuated at the highest tangent levels by low signal to noise ratios. A number of inversion techniques have been formulated, tested and successfully applied to atmospheric data that are less susceptible to error propagation. In the Mill and Drayson(1977) method the inversion starts at the lowest tangent level where the highest signals are typically found and proceeds upwards. The profile at and above the tangent level is adjusted with a constant factor derived from the difference between the measured and calculated signal. Measurement errors are dispersed over the full slant path rather than just the tangent level as is the case for the standard onion peel. The method of Carlotti(1988) takes a global-fit approach to limb inversion. At each update step the profile is fit in a least squares sense to the set of limb measurements. Both techniques appear to offer an improvement over the standard onion peel method.

© 1993 Optical Society of America