Error analysis for retrieval of urban atmospheric aerosol properties from downwelling infrared radiation spectra.
The possibility of retrieval of urban aerosol physical properties from downwelling atmospheric infrared radiation spectra between 700 and 1400 cm(-1) with 0.24-cm(-1) spectral resolution, which can be obtained from the tropospheric infrared interferometric sounder developed by the Central Research Institute of Electric Power Industry, was estimated from error analysis of the least-squares fit method. The error analysis for retrieval of the aerosol extinction coefficient spectra in three atmospheric layers (boundary, free troposphere, and stratosphere) showed the retrievability only of the boundary layer. Based on this result, we propose the retrieval for particle number density of each aerosol component, which is one of the parameters for the aerosol size distribution function, using the boundary aerosol extinction coefficient spectra. We assume that aerosols in urban areas consist of three types of component, namely, water soluble, soot, and dustlike. Under this assumption, we estimated the error of the retrieved volume density for each aerosol component. For the estimation we used the least-squares fit of Mie-generated spectral extinction coefficients. The estimated error shows that the volume density of each aerosol component in an urban boundary layer is equivalent to the retrieval target. We also show that the aerosol properties can be retrieved with higher accuracy when the effects of multiple scattering by aerosols are included in the retrieval procedure.
Shimota
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A
Komae Research Laboratory, Department of Atmospheric Science, Central Research Institute of Electric Power Industry, 2-11-1 Iwado kita, Komae-shi, Tokyo 201-8511, Japan. akiro@criepi.denken.or.jp
Kobayashi
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H