Egrett
Grob G-520 Egrett

The Scanning Spectral Polarimeter (SSP) is an airborne polarimeter developed by Colorado State University. It uses a rotating optical bandpass filter to measure spectral radiance and fluxes across the 400 to 4000 nm wavelength range. These measurements help to determine cloud optical and microphysical properties. SSP has an accuracy of about 3% and a field of view of 20 mrad.

The Total Solar Broadband Radiometer (TSBR) is a ground-based or airborne radiometer operated by the Department of Energy (DoE) Atmospheric Radiation Measurement (ARM) User Facility. It measures total solar irradiance across wavelengths from 0.224 to 3.91 μm. TSBR uses electrically calibrated pyroelectric detectors and has a hemispherical field of view. It usually operates as part of the Radiation Measurement System (RAMS) instrument package alongside the Fractional Solar Broadband Radiometer (FSBR).

The Total Direct Diffuse Radiometer (TDDR) is a passive radiometer that measures solar irradiance. It can be used for airborne and ground-based operations. TDDR measures total and diffuse irradiance by rotating a shadow arm before the radiometer. These measurements can be used to calculate the direct solar irradiance. TDDR operates across the 0.38-1.6 μm spectral range with a 0.01 μm bandwidth.

The Fractional Solar Broadband Radiometer (FSBR) is an airborne broadband radiometer that is typically utilized as part of the Radiation Measurement System (RAMS) instrument suite. It measures fractional downwelling shortwave radiation. FSBR covers a portion of the near-infrared spectrum between 0.68 and 3.3 µm and has a data frequency of 9 Hz. FSBR can be deployed on ground-based platforms as well and is a complementary instrument to the Total Solar Broadband Radiometer (TSBR).

The Radiation Measurement System (RAMS) is an airborne passive radiometer that measures broadband solar irradiance. RAMS includes two radiometers: the Total Solar Broadband Radiometer (TSBR) and the Fractional Solar Broadband Radiometer (FSBR). The TSBR operates in the 0.224 to 3.91 μm range, while the FSBR operates between 0.68 and 3.3 μm. It has a response time of approximately 60 milliseconds and can provide measurements every 5 meters for aircraft speeds around 75 m/s. RAMS is primarily used for airborne operations but can also be used to collect ground-based measurements.