The retrieval of stratospheric aerosol size distributions based on HALOE multi-wavelength particle extinction measurements was described by Hervig et al. [1998].  That approach yields unimodal lognormal size distributions,  which describe the aerosol concentration versus radius using three parameters:  total aerosol concentration,  median radius,  and distribution width.   This site offers results based on the Hervig et al. [1998] technique,  with one exception.  The retrieval results reported here are based on sulfate refractive indices for 215 K,  where Hervig et al.  [1998] used room temperature indices adjusted to stratospheric temperatures using the Lorentz-Lorenz rule.  Size distributions were only retrieved at altitudes above tropospheric cloud tops.  Clouds were identified using techniques described by Hervig and McHugh [1999]. 

The HALOE size distributions are offered in NetCDF files containing data for a single year.  The results are reported on a uniform altitude grid ranging from 6 to 33 km at 0.3 km spacing.  The native HALOE altitude spacing is 0.3 km,  so this interpolation has little or no effect on the data.  The files report profile data including: