Instrument : Multifilter Rotating Shadowband Radiometer (MFRSR)
The multifilter rotating shadowband radiometer (MFRSR) takes spectral measurements of direct normal, diffuse horizontal and total horizontal solar irradiances. These measurements are at nominal wavelengths of 415, 500, 615, 673, 870, and 940 nm. The measurements are made at a user-specified time interval, usually about one minute or less. The sampling rate for the Atmospheric Radiation Measurement (ARM) Climate Research Facility MFRSRs is 20 seconds. From such measurements, one may infer the atmosphere's optical depth at the wavelengths mentioned above. In turn, these optical depths may be used to derive information about the column abundances of ozone and water vapor (Michalsky et al. 1995), as well as aerosol (Michalsky et al. 1994) and other atmospheric constituents.
A silicon detector is also part of the MFRSR. This detector provides a measure of the broadband direct normal, diffuse horizontal and total horizontal solar irradiances. A MFRSR head that is mounted to look vertically downward can measure upwelling spectral irradiances. In the ARM system, this instrument is called a "multifilter radiometer (MFR)". At the Southern Great Plains (SGP) there are two MFRs; one mounted at the 10-m height and the other at 25 m. At the North Slope of Alaska (NSA) sites, the MFRs are mounted at 10 m. MFRSR heads are also used to measure "normal incidence" radiation by mounting on a solar tracking device. These are referred to as normal incidence multi-filter radiometers (NIMFRs) and are located at the SGP and NSA sites. Another specialized use for the MFRSR is the narrow field of view (NFOV) instrument located at SGP. The NFOV is a ground-based radiometer (MFRSR head) that looks straight up.
Output Value-Added Products
This instrument is an input to the following value-added products, which provide improved measurements or derived quantities.
- mfrsraod1mich : MFRSR: derived total & aerosol optical depth from 1st Michalsky algorithm
- mfrsrcldod1min : Derived: Cloud Optical Properties from MFRSR, MWR, Langley Analysis
- nimfraod1mich : NIMFR: derived total & aerosol optical depth from 1st Michalsky algorithm
- qcrad1long : Surface Radiation Measurement Quality Control testing, including climatologically configurable limits
- qcradbeflux1long : Surface Radiation Measurement (BEFLUX input) QC testing, incl. climatologically configurable limits
- qcradbrs1long : Surface Radiation Measurement (BRS input) QC testing, incl. climatologically configurable limits
- sasheniraod : Shortwave Array Spectroradiometer-Hemispheric, NIR Aerosol Optical Depths
- sashevisaod : Shortwave Array Spectroradiometer-Hemispheric, VIS Aerosol Optical Depths
- mfrsr : Multi-Filter Rotating Shadowband Radiometer (MFRSR): irradiances
The following measurements are those considered scientifically relevant.
- Cloud optical depth
- Shortwave narrowband diffuse downwelling irradiance
- Shortwave narrowband direct normal irradiance
- Shortwave narrowband total downwelling irradiance