Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece
- ISSN: 16807324
- DOI: 10.5194/acp-13-3733-2013
Pyranometer measurements of the solar surface radiation (SSR) are\navailable at many locations worldwide, often as long time series\ncovering several decades into the past. These data constitute a\npotential source of information on the atmospheric aerosol load. Here,\nwe present a method for estimating the aerosol optical depth (AOD) using\npyranometer measurements of the SSR together with total water vapor\ncolumn information. The method, which is based on radiative transfer\nsimulations, was developed and tested using recent data from\nThessaloniki, Greece. The effective AOD calculated using this method was\nfound to agree well with co-located AERONET measurements, exhibiting a\ncorrelation coefficient of 0.9 with 2/3 of the data found within +/-\n20% or +/- 0.05 of the AERONET AOD. This is similar to the performance\nof current satellite aerosol methods. Differences in the AOD as compared\nto AERONET can be explained by variations in the aerosol properties of\nthe atmosphere that are not accounted for in the idealized settings used\nin the radiative transfer simulations, such as variations in the single\nscattering albedo and Angstrom exponent. Furthermore, the method is\nsensitive to calibration offsets between the radiative transfer\nsimulations and the pyranometer SSR. The method provides an opportunity\nof extending our knowledge of the atmospheric aerosol load to locations\nand times not covered by dedicated aerosol measurements.