The CIMEL CE-318 sun photometer of CIAO is operational within AERONET, the reference network of Sun-photometer ground-based aerosol measurements. The CIMEL CE-318 measures atmospheric aerosol columnar properties. This is a multi-channel, automatic sun-and-sky scanning radiometer that measures the direct solar irradiance and sky radiance at the Earth’s surface. It  provides the aerosol optical depth (AOD) at 340, 380, 440, 500, 675, 870, 1020 and 1640nm, along with the water vapour column content and the estimation of several optical and microphysical aerosol properties, such as the refractive index and the size distribution.

The system is fully automatic and powered using solar panels. The measured radiances are automatically sent to the NASA-GSFC where they are processed according to the AERONET data analysis. A cloud mask is also applied to remove cloud contamination. The system is calibrated, on average, once per year and after the calibration procedure the lv2.0 quality assured data are released on the AERONET website. Since June 2010, CIAO sun photometer is also running using the new AERONET “cloud mode” capability with the aim to improve cloud optical depth observations.

The co-location of multi-wavelength Raman lidar and Sun-photometer instrument provides an optimal benchmark for comparison and integration of passive and active remote sensing techniques for aerosol study.

Data available at AERONET sitehttp://aeronet.gsfc.nasa.gov/

Link to relatet projects:
ACTRIS: www.actris.net 
GEOmon: http://www.geomon.eu
 
Contact person: Lucia Mona