@article{Koue_2023, title={EFFECTS OF STRONG WINDS ON THE BOTTOM LAYER DURING THE WEAK STRATIFICATION PERIOD IN LAKE BIWA, JAPAN}, volume={24}, url={https://geomatejournal.com/geomate/article/view/3766}, abstractNote={<p>In recent years, a decrease in dissolved oxygen in the lake bottom has been observed in the northern part of Lake Biwa, the largest freshwater lake in Japan. The main physical controlling factor is considered to be changes in stratification, which are influenced by weather and climatic conditions. As atmospheric temperature increases, lake surface temperature rises, and stratification is formed. The strength of stratification has a significant impact on the transport of various material cycles, such as dissolved oxygen and nutrients, from the lake surface to the bottom layer. Therefore, in this study, the analysis of the effect of strong winds during the stratification collapse period (autumn) on the stratification structure of Lake Biwa was performed. Baseline simulations using actual meteorological data and experimental simulations using meteorological data with modified wind speed and direction were conducted. The numerical experiments showed that collapse of stratification was more likely to occur in autumn than in summer, and vertical mixing was enhanced. When strong winds blew more in one direction, vertical mixing was further enhanced when the duration of strong winds was longer during periods of weak stratification, as well as the results during the stratification period. When winds of the same magnitude as during the stratification period blew during periods of decreasing water temperature, a decrease in bottom water temperature was observed prior to the full-layer circulation in the following year. This suggested that strong winds during the decreasing temperature period had a strong influence on the water temperature environment next year</p>}, number={104}, journal={GEOMATE Journal}, author={Koue, Jinichi}, year={2023}, month={Mar.}, pages={44–52} }