Retrieval Analysis of Aerosol Properties Deduced From Extinctions at SAGE II, SAGE III, and HALOE Wavelengths

SAGE II measures aerosol extinctions at four visible and near IR wavelengths. SAGE III measures aerosol extinctions at five additional wavelengths; the longest one is 1.55 micron. On the other hand, all HALOE aerosol channels are at IR wavelengths ranging from 2.45 to 5.26 micron. There are comparison opportunities when HALOE and SAGE II or SAGE III conduct measurements at close locations and times. The advantages of the following three methods of approach are discussed: (1) Converting HALOE aerosol extinctioni to extinctions at SAGE III wavelengths; (2) Converting either SAGE II or SAGE III aerosol extinctions to extinctions at HALOE wavelengths; (3) Deducing aerosol properties from SAGE II, SAGE III, and HALOE extinction measurements. It is found that in general, the conversion to extinction at 1.55 micron from HALOE measurements is more accurate than other approaches. It is also found that the retrieval uncertainty is highly dependent on the measurement uncertainty associated with each data set. The preliminary results of comparing HALOE with SAGE II or SAGE III are presented and the relatively larger discrepancies shown at higher altitudes are discussed.