Thermoprofiling System for Online Monitoring of the Active Layer Based on the Deep-Water Neutrino Telescope Baikal-GVD

Abstract

For continuous monitoring of the vertical distribution of temperature in Lake Baikal, as an indirect measure of dynamic processes, a system of distributed temperature sensors was developed in the Laboratory of Hydrology and Hydrophysics of the Limnological Institute of the SB RAS. The system allows to obtain instant vertical temperature profiles with up to 1 Hz frequency and 1 mK resolution. Additionally, each sensor is equipped with a microheater activated by adressed command to implement the thermanemometric mode of operation, to estimate the velocity of water flows. The pilot sample of the thermistor chain contains 11 temperature sensors located along the depth from 20 to 120 meters with a 10 meters step, and covers the active layer of Lake Baikal with the major changes during the year. The developed thermistor chain was integrated into one of the strings of the BaikalGVD neutrino telescope and connected to the specially developed data logger which placed in the telecommunication spherical module. In this article, we give a brief description of the temperature profiling system and preliminary results of tests in the open Baikal during 2022. The obtained measurement results allowed us to consider the temporal variability of the active layer temperature by analyzing its power spectral density. The developed monitoring system allows obtaining qualitatively new hydrophysical data on the state of the active layer of the pelagic part of Lake Baikal in real time.