Study on summer and winter seasonal variation characteristics of the absorption and scattering coefficients of a typical urban landscape lake in Hangjiahu Plain

Using the Inherent Optical Properties (IOPs) and water quality analysis data of the water samples from Nanhu (a typical urban landscape lake in Hangjiahu Plain) measured in the laboratory in August and December 2023, we experimentally determined and calculated the absorption coefficient, scattering coefficient, and light attenuation coefficient of the water body in summer and winter, and analyzed the dominant factors affecting light attenuation in different seasons. The results indicate that the absorption, scattering, and light attenuation effects of each component of the water body in Nanhu during the summer are higher than those in winter. The average values of a(λ), b(λ), and c(λ) in summer are 2.36 m^-1 , 2.80 m^-1 and 5.16 m^-1 , respectively, while in winter, these values are 0.69 m^-1 , 1.16 m^-1 , and 1.85 m^-1 , respectively. This suggests that the water body components contributing to light attenuation exhibit certain differences in absorption and scattering characteristics between summer and winter. Regardless of the season, whether it is winter or summer, the contribution of components to the total light attenuation in Nanhu follows the order: non-algal particles⪆algal particles⪆CDOM (colored dissolved organic matter)⪆pure water. Inorganic particles are the dominant factor causing light attenuation in Nanhu water, with algal particles being the secondary contributor. In summer, the contributions of the absorption and scattering effects of each component of the water body in Nanhu are essentially equivalent, whereas, in winter, the scattering effect is significantly higher than the absorption effect.