Sun photometry

Starting date: 29-7-2015
Status: Running
Instrumentation and calibration: At ICO-OV, during warm months (i.e. May - September), solar direct radiation is measured within four narrow spectral channels (368, 412, 500 and 862 nm) by means of a Precision Filter Radiometer (PFR) manufactured and calibrated by the Physikalisch-Meteorologisches Observatorium Davos (PMOD) . The instrument is installed on a custom solar tracker provided by ISAC-CNR. From the measured signals the Aerosol Optical Depth (AOD) at the four channels and the Angstrom parameter are obtained. Calibration of the instrument is also performed onsite by means of the Langley method. The instrument and the tracker are placed on the terrace of ICO-OV.
Project affiliation (s) Present: Nextdata
Related research programmes

  • Tropospheric background condition
  • Long-range transport
  • Saharan dust transport
  • Polluted air-masses

Why is this research important? This research is important because aerosols in the atmosphere play a key role in the definition of the Earth's climate, both directly and via modification of the cloud properties. The aerosol optical depth (AOD) is defined as the measure of the extinction (due to scattering and absorption) of the solar radiation reaching the ground due to the atmospheric columnar aerosol load. This variable is one of the five core observable variables which characterize the atmospheric aerosol (GAW Aerosol Guidelines, 2003) and it is considered a priority for a global surface-based network. Hence, AOD gives a measure of the total vertical content of aerosols and it is important both to evaluate the aerosol radiative and climatic effects and to monitor the long- range transport of air-masses. For example, Saharan dust transported from North Africa, frequently reaches Italy and, when deposited on the surface, contributes to the determination of PM10. This, as for aerosols in general, has effects also on the human health.
Quick look

Hourly averages of AOD and Angstrom exponent values measured at ICO-OV during last 10 days. Sun-photometry measurements are not carried out during Autumn-Winter

Where can I find the data? By direct request to: m.mazzola [at]
Organization (s): ISAC-CNR Via Gobetti 101, I-40129, Bologna
Contact persons: Dr. Angelo Lupi e-mail: a.lupi [at] phone: +39 051 6399592 Dr. Mauro Mazzola e-mail: m.mazzola [at] phone: +39 051 6399592