Given the development of sun- and lunar-photometry technique by indipendent institutions over many years, several different sustems are used to retrieve AOD. The following are all models of photometers that have been used to acquire data that can be found in the POLAR-AOD network.
| Name | Multifilter Rotating Shadowband Radiometer |
| Measured values | Global and diffuse irradiance |
| Wavelengths (nm) | 415, 500, 615, 673, 870, and 940 |
MFRSR measures both the global and diffuse components of solar irradiance using six narrowband channels and one broadband channel. To collect one data record, the instrument takes measurements at four different shadowband positions.
| Name | CIMEL CE318-T |
| Measured values | Direct solar irradiance and sky irradiance |
| Wavelengths (nm) | 340, 380, 440, 500, 675, 870, 937, 1020, and 1640 |
The CIMEL 318T is a highly precise sun photometer that measures direct solar irradiance and sky radiance at various wavelengths in the visible and near-infrared spectral range. The instrument is equipped with automated calibration, data acquisition, and quality control systems. The CIMEL 318T is also part of the Aerosol Robotic Network (AERONET).
| Name | Skyradiometer POM-02 |
| Measured values | Direct and diffuse solar irradiance |
| Wavelengths (nm) | 315, 340, 380, 400, 500, 675, 870, 940, 1020, 1627, and 2200 |
The POM-02 Skyradiometer measures circum-solar radiation and spectrum intensity of the direct solar radiation for the purpose of studying the size distribution and concentration of aerosols in the atmosphere. In addition to the features of the POM-01, the POM-02 also measures long-wavelength radiation. It is part of the SKYNET network.
| Name | Precision Filter Radiometer |
| Measured values | Direct solar irradiance |
| Wavelengths (nm) | 368, 412, 500, and 862 |
PMOD/WRC developed the Precision Filter Radiometer (PFR) during the 90’s and used it for long term AOD measurements under GAW-PFR network started in Switzerland in 1999.
| Name | SP02 |
| Measured values | Direct solar irradiance |
| Wavelengths (nm) | 413, 500, 676, amd 860 |
Middleton Solar SP02 Sunphotometer is a simple low-cost instrument for the determination of the spectral optical depth of the atmosphere. It can be configured for total & aerosol optical depth measurement, column ozone measurement, and assessment of water vapour amounts.