A new analytical approach for retrieval of the vertically weighted chlorophyll a concentration ( $〈\text{Chl}{〉}_{\text{rs}}$ ) detected by remote sensors is presented. Model calculations were carried out for the turbid waters of Lake Kinneret, Israel, and showed that $〈\text{Chl}{〉}_{\text{rs}}$ may be replaced by the average chlorophyll a concentration ( $〈\text{Chl}{〉}_{\mathrm{p}}$ ) within the upper “penetration layer” $0–Z_{\mathrm{p}}$ . The study also showed a high correlation between $〈\text{Chl}{〉}_{\text{rs}}$ and Chl concentration averaged in the other depth layers, namely, the $0–1\mathrm{m}$ layer, the euphotic layer ( $0–Z_{\mathrm{e}}$ ), and the production layer ( $0–Z_{\text{pr}}$ ). Our findings are closely related to models developed for the world ocean, with the exception of periods when the dinoflagellate Peridinium gatunense blooms in the lake. We showed the effect of the pattern of vertical Chl distributions within the penetration layer on the difference between $〈\text{Chl}{〉}_{\text{rs}}$ and other Chl indices was conspicuous when the Chl maximum was in the uppermost $0–5\mathrm{m}$ layer of the water column. We assume that the presented approaches are instrumental for further development of optimal, locally adapted algorithms for remote sensing of Chl in any type of natural waters.