Inverse problems in remote sensing of planetary atmospheres

Moustafa T. Chahine
Jet Propulsion Laboratory
Atmospheric Sciences

The outgoing radiance from a planetary atmosphere carries with it information about the composition (such as H2O, O3) and structure (such as temperature) of the atmosphere and the surface. The fundamental inverse problem here is to determine the vertical structure of the atmosphere f (z) from observations of the outgoing radiance as a function of frequency R (?), or given R (?) = N f (z), find f (z) = N –1 R (?) where N is a nonlinear integral operator. In general, clouds also affect the outgoing radiance at most wavelengths and introduce uncertainties that must be taken into account.
Our presentation will be structured in two parts. First we present an approach to eliminate the effects of clouds and reconstruct the “clear column” radiance emitted by the clear portions of the atmosphere. Then, we present a mapping transformation that maps variations of the clear column radiance R as a function of ? into variations of f as a function of z and generalize this approach to account for noise in observations and uncertainties in our knowledge of the radiative transfer of the atmospheric medium.
Second, We will apply this approach to analyze actual spectral data measured by a high spectral resolution sounder AIRS* (the Atmospheric Infrared Sounder) currently in orbit around Earth on the NASA Aqua satellite and compare the retrieved results with available data including in situ measurements made by weather balloons.

1 Jet Propulsion Laboratory/California Institute of Technology
2 NASA Goddard Space Flight Center
3 National Oceanic and Atmospheric Administration
* see (http://www.jpl.nasa.gov/airs/)


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