A method for determining a scattered light parameter, for example turbidity, in a medium using a measuring arrangement, the method including the steps of: transmitting excitation light into the medium, wherein the excitation light is scattered in the medium; receiving the light scattered in the medium; transmitting excitation light into the medium towards the medium surface, wherein the excitation light is reflected at the medium surface; receiving the light reflected from the medium surface; and determining the scattered light parameter, in particular turbidity, from the scattered light and reflected light. The present disclosure further discloses a measuring arrangement for performing the method.

An online detection device underwater elements includes an LIBS system in a sealing pressure chamber and an external airflow control system. The airflow control system has a gas probe bin and a gas source. An opening is formed at one end of the gas probe bin while the other end and the sealing pressure chamber are hermetically partitioned through a glass window. A laser in the LIES system outputs laser to an underwater object surface to be detected for generating plasma spectra. A spectrometer collects plasma spectra returned along an original optical path. When the device operates in water, the balance gas storage tank produces gas with the same pressure as underwater. A flow model is invoked according to the current water pressure to accurately control the air flow rate to form a stable gas environment in the gas probe, which improves the plasma excitation and collection efficiency.

Disclosed is an optical probe device for analyzing a component of an underwater substance, the optical probe device including: a light source unit for emitting excitation light; a sensing unit for emitting the excitation light into underwater and collecting scattered light scattered from the underwater; a spectroscopy unit for analyzing the scattered light; a light transmitting unit for connecting the light source unit and the sensing unit, and the sensing unit and the spectroscopy unit; and a cap having an opening on one side, configured to receive the sensing unit therein, and configured to allow an air layer inside the opening to separate the sensing unit from an underwater environment when the opening is lowered and submerged in the underwater in the state where the opening is disposed to cover a water surface.

Disclosed is a modularized-reconfigurable long-term in-situ monitoring device and a monitoring method. The monitoring device comprises a fixed component. The fixed component is provided with a physical and chemical parameter sensor interface, a multi-channel Raman detection system, a camera system, an ocean current recording system, a control system, a power supply system, a lighting system, a floating body and an optical communication system. A releaser is arranged in the middle of the top of the fixed component. The releasing end of the releaser is connected with one end of a connecting rod penetrating through the fixed component, and the other end of the connecting rod is connected with a bottom counterbalance weight through a manual releaser. The working efficiency is improved, the operation risk is reduced, and the positioning precision is high.