In-Situ Stratospheric Size Distribution Measurements from 2006 – 2015: comparisons with OSIRIS and OMPS extinction products

Abstract:

The University of Wyoming has been flying Optical Particle Counters (OPCs) on high-altitude balloons since 1971 (Deshler et al., 2003). These measurements constitute the only long-term in-situ observational record of stratospheric aerosol size distributions. In the early 2000’s, the program began flying a new OPC with detection capability down to 75 nm radius. As part of the characterization of the new instrument, 10 years of balloon-borne measurements are compared to both the OSIRIS and OMPS extinction profiles. At each altitude, a bimodal size distribution is fit to the binned OPC data and then converted to extinction for the appropriate wavelengths via Mie theory. Comparisons between the OPC size distributions and OMPS profiles during 12 flights in a 3-year-period reveal agreement in extinction to within 10% across the 16-22 km altitude range. The flight-by-flight comparisons to OSIRIS across the 2006-2013 time period are more variable, with the largest difference being 50%.