Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece 1Kuopio Unit, Finnish Meteorological Institute, Kuopio, Finland
09 Apr 2013
2Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
3National Observatory of Athens, Athens, Greece
4Climate Change Unit, Finnish Meteorological Institute, Helsinki, Finland
5Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
Received: 13 August 2012 – Published in Atmos. Chem. Phys. Discuss.: 20 December 2012 Abstract. Pyranometer measurements of the solar surface radiation (SSR)
are available at many locations worldwide, often as long time series
covering several decades into the past. These data constitute a potential
source of information on the atmospheric aerosol load. Here,
we present a method for estimating the aerosol optical depth (AOD)
using pyranometer measurements of the SSR together with
total water vapor column information. The method, which is
based on radiative transfer simulations, was developed
and tested using recent data from Thessaloniki, Greece.
The effective AOD calculated using this method was found to
agree well with co-located AERONET measurements, exhibiting
a correlation coefficient of 0.9 with 2/3 of the data
found within ±20% or ±0.05 of the AERONET AOD. This is
similar to the performance of current satellite aerosol methods. Differences in the
AOD as compared to AERONET can be explained by variations in the
aerosol properties of the atmosphere that are not accounted for in
the idealized settings used in the radiative transfer simulations, such as
variations in the single scattering albedo and Ångström exponent.
Furthermore, the method is sensitive to calibration offsets between the
radiative transfer simulations and the pyranometer SSR. The method
provides an opportunity of extending our knowledge of the
atmospheric aerosol load to locations and times not covered by
dedicated aerosol measurements.
Revised: 11 March 2013 – Accepted: 20 March 2013 – Published: 09 April 2013
Citation: Lindfors, A. V., Kouremeti, N., Arola, A., Kazadzis, S., Bais, A. F., and Laaksonen, A.: Effective aerosol optical depth from pyranometer measurements of surface solar radiation (global radiation) at Thessaloniki, Greece, Atmos. Chem. Phys., 13, 3733-3741, doi:10.5194/acp-13-3733-2013, 2013.