From the ARM Instruments MFRSR web page: "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."
Data Quality Guidance
From the standard Data Quality Assessment: "Due to the logger/instrument combination being used at NSA and the cold temperatures, the head_temp rapidly fluctuates and constantly fails the delta QC. This has been stated by the instrument mentor as normal operating behavior for the MFRSR at the NSA site and will not be mentioned in the DQA."