Measurements of spectral aerosol optical thickness (tau), single scattering albedo (SSA), refractive index (RI), and size distribution of aerosols for preset aerosol diameters (um - microns) made using sunphotometers between June 2001 - December 2023 located on the roof of Plymouth Marine Laboratory (PML), Devon, UK, for the Western Channel Observatory (https://www.westernchannelobservatory.org.uk) and The North Atlantic Climate System Integrated Study (ACSIS).

This version 1 dataset contains measurements for 2001 to 2023. Two Kipp and Zonen (UK) PREDE POM01-L sunphotometers were used: June 2001 - March 2008 (Unknown serial number) and August 2009 - December 2023 (Serial Number PS08015).

The instruments operated at 7 wavelengths (315, 400, 500, 670, 870, 940 and 1020nm) and scanned at pre-set angles away from the solar disk to determine, using the inversion code of Nakajima et al. (1996), various optical properties of tiny particles called aerosols within the atmospheric column.