Ground-based UV-VIS MFRSR Spectral Aerosol Absorption Dataset of Saharan Dust at Izaña Observatory

A synergistic approach combining the spectral aerosol optical depth measurements from Aerosol Robotic Network (AERONET) and diffuse-to-direct irradiance measurements from the UV- and Vis-Multifilter Rotating Shadowband Radiometer (MFRSR), along with trace gas data from satellites, allows consistent retrievals of atmospheric dust aerosol columnar effective imaginary refractive index (k), single scattering albedo (SSA), and absorption aerosol optical depth (AAOD). The approach is demonstrated on the data collected at the Izaña Atmospheric Observatory (IZO), located at an altitude of 2.4 km on Tenerife Island, a unique site for Saharan dust column optical properties retrievals due to very clean background condition for calibrating the instrument. The calibration of MFRSR measurements relies on observations acquired on cleaner days (AOD<0.1 at 440 nm) to eliminate the observed dependency of the calibration constant on increasing dust aerosol loading. An inversion algorithm uses the AERONET-MFRSR collocated measurements and fits the measured ratio of diffuse to direct-normal irradiance for discrete wavelengths (325, 332, 340, 380, and 440 nm) to the pre-calculated, on-the-fly look-up table, while accounting for the pre-defined spheroidal shape distribution of the dust aerosols, to retrieve the spectral imaginary part of the refractive index. The multiyear (2019-2023) dataset of UV-VIS spectral aerosol absorption is presented here. This dataset is associated with the following publication: Jethva, H., Krotkov, N., Torres, O., Mok, J., Labow G., Lind, E., Eck, T., Gao, W., Janson, G., Simpson, S., Sharp, D., Lantz, K., Wilson, C., Barreto, A., García, R., Korkin, S., Flittner, D.: Ground-based MFRSR UV-Vis spectral retrievals of Saharan dust absorption at Izaña Observatory, Atmos. Meas. Tech., Accepted, 2026.