Ultraviolet Fluorescence LiDAR (UFL) as a Measurement Tool for Water Quality Parameters in Turbid Lake Conditions

Abstract

Despite longstanding contributions to oceanography, similar use of fluorescence light detection and ranging (LiDAR) in lake settings is not routine. The potential for ship-mounted, multispectral Ultraviolet Fluorescence LiDAR (UFL) to provide rapid, high-resolution data in variably turbid and productive lake conditions are investigated here through a series of laboratory tank and field measurements carried out on Lake Balaton, Hungary. UFL data, calibrated empirically to a set of coinciding conventionally-analyzed samples, provide simultaneous estimates of three important parameters-chlorophyll a(chla), total suspended matter (TSM) and colored dissolved organic matter (CDOM). Successful UFL retrievals from both laboratory and field measurements were achieved for chla (0.01-378 mg·m 4406Cylindrospermopsis raciborskii, and chlorophyta, Scenedesmus armatus). The ratio between fluorescence emissions measured at 650 nm, related to the phycocyanin fluorescence maximum, to that at 685 nm is demonstrated to effectively distinguish these two species. Validation through both laboratory measurements and field measurements confirmed that site specific calibration is necessary. This study presents the first known assessment and application of ship-mounted fluorescence LiDAR in freshwater lake conditions and demonstrates the use of UFL in measuring important water quality parameters despite the more complicated hydro-optic conditions of inland waters.

Structure of the buoyant plume formed by Ob and Yenisei river discharge in the southern part of the Kara Sea during summer and autumn

“…The explicit description of the UFL instrument and the algorithms used for retrieving Chl‐a, TSM, and CDOM are given in Palmer et al . [] and Pelevin et al . [].…”

“…Optical remote sensing was performed by a ship-mounted ultraviolet fluorescent LiDAR (UFL) and was used to derive simultaneous concentrations of chlorophyll a (Chl-a), total suspended matter (TSM), and colored dissolved organic matter (CDOM) at the sea surface with a 250 m spatial resolution along the ship track. The explicit description of the UFL instrument and the algorithms used for retrieving Chl-a, TSM, and CDOM are given in Palmer et al [2013] and Pelevin et al [2017].…”

Spatio-seasonal variability of chromophoric dissolved organic matter absorption and responses to photobleaching in a large shallow temperate lake

“…The hypertrophic Kis-Balaton wetland system is believed to be responsible for much of the DOM entering the lake, largely derived from luxuriant growth and decomposition of aquatic plants. Previous research (Palmer et al, 2013;Riddick et al, 2015) has shown that CDOM is usually significantly higher close to the Zala River inflow, and decreases towards the outflow but very little is known about the seasonal dynamics of CDOM in the system. Suspended particulate matter in Lake Balaton is highly variable (spatially and temporally) due to its very shallow depth, constant mixing and susceptibility to wind-driven resuspension events (Istvánovics et al, 2004).…”

Small river plumes off the northeastern coast of the Black Sea under average climatic and flooding discharge conditions

“…The measurements were performed along the ship track using a ship-mounted pump-through system equipped with a CTD (conductivity, temperature, and depth) instrument (SeaBird SBE911) and the ultraviolet fluorescent lidar (UFL-9) and were organized as cross-shore transects; the distances between neighboring transects near the river estuaries were 100-150 m. Additionally, vertical profiles of salinity were measured within the river plumes using a CTD instrument (SeaBird SBE19plus). The explicit description of the lidar instrument and the algorithms used for retrieving TSM, CDOM, and Chl-a are given in Palmer et al (2013). Detailed information about the field surveys and the measurements described above can be found in .…”