Monitoring of optical properties of deep waters of Lake Baikal in 2024

We present the results of the one-year (03.2024-03.2025) monitoring of inherent optical properties (IOP) of Baikal deep waters in wavelength range of 400–620 nm within the effective volume of the deep underwater neutrino telescope Baikal-GVD, which were measured by a BAIKAL-5D Unit 2 at depth 1180 m. Measurements of the absorption spectrum, scattering length at three points of the spectrum (405nm, 460, 532nm) and small-angle dependence of the scattering function were carried out weekly. The results of measurements of the integral characteristics of the scattering function and the absorption and scattering coefficients in the 2024 expedition are also presented. Data on the angular and integral scattering characteristics made it possible to calculate corrections to compensate for the instrumental error in measuring the absorption and scattering coefficients. The obtained data allow us to estimate the range of changes in the absorption and scattering lengths over a sufficiently long period of time and to investigate the relationship between the processes of changes in absorption and scattering.