Potential of Mie–Fluorescence–Raman Lidar to Profile Chlorophyll a Concentration in Inland Waters

Abstract

Vertical distribution of phytoplankton is crucial for assessing the trophic status and primary production in inland waters. However, there is sparse information about phytoplankton vertical distribution due to the lack of sufficient measurements. Here, we report, to the best of our knowledge, the first Mie–fluorescence–Raman lidar (MFRL) measurements of continuous chlorophyll a (Chl-a) profiles as well as their parametrization in inland water. The lidar-measured Chl-a during several experiments showed good agreement with the in situ data. A case study verified that MFRL had the potential to profile the Chl-a concentration. The results revealed that the maintenance of subsurface chlorophyll maxima (SCM) was influenced by light and nutrient inputs. Furthermore, inspired by the observations from MFRL, an SCM model built upon surface Chl-a concentration and euphotic layer depth was proposed with root mean square relative difference of 16.5% compared to MFRL observations, providing the possibility to map 3D Chl-a distribution in aquatic ecosystems by integrated active–passive remote sensing technology. Profiling and modeling Chl-a concentration with MFRL are expected to be of paramount importance for monitoring inland water ecosystems and environments.

A Systematic Review of the Application of the Geostationary Ocean Color Imager to the Water Quality Monitoring of Inland and Coastal Waters

“…The development of unmanned aerial vehicles includes improved sensors and payloads, enhanced flight control systems, miniaturization, lightweight design, and higher battery life [225][226][227]. Ground observation technology progress includes improving sensors and algorithms, providing more accurate estimates of water quality parameters, and the ability to monitor continuously, in the long term, in real time, and automatically [228,229]. The GOCI can be used to produce water quality products in clear weather.…”

“…to monitor continuously, in the long term, in real time, and automatically [228,229]. The GOCI can be used to produce water quality products in clear weather.…”

Investigating Algal Sensor Utilization Methods for Three-Dimensional Algal Control Technology Evaluation

“…Complementing traditional microscopic analysis, sensor-based measurements enable real-time monitoring, depth-specific measurements, and horizontal assessments [67]. In addition, depth-specific sensor measurements are important for assessing trophic status and primary production [68]; therefore, sensors were utilized in this study. Among the sensors, the FluoroProbe (FP) sensor is known for its effectiveness in determining phytoplankton trends.…”