Dresden 2026 – scientific programme
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UP: Fachverband Umweltphysik
UP 7: Aquatic Systems: Limnology, Natural Waters, Wetlands and Soilmoisture
UP 7.1: Talk
Wednesday, March 11, 2026, 11:15–11:30, MER/0002
One Dimensional Thermobaric Mixing in a Deep Lake — •Joshua Marks1,2, Kazuhisa A. Chikita3, and Bertram Boehrer1,2 — 1Department of Lake Research, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany — 2Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany — 3Arctic Research Center, Hokkaido University, Sapporo, Japan
Thermobaricity is defined as the temperature dependence of the compressibility of water. It leads to a decrease of the temperature of maximum density Tmd with increasing pressure. This effect has significant impacts in many deep lakes, like Lake Shikotsu, Hokkaido, Japan. Despite this, it is often not implemented in lake models, except in combination with external forcing. We created a simplified 1D model with the surface temperature input as only external forcing, excluding salinity and any other competing influences. For stability considerations, we used the in-situ density. The model recreated the one dimensional deep water renewal with the following key features: (1) at the intersection of the temperature profile with the Tmd line diffusion induces cabbeling which leads to thermobaricity driven deep water circulation, (2) this deep water circulation cell is detached from the surface, (3) the deep water stays isothermal, (4) and after the winter stratification the temperature profile aligns with the Tmd line. The results emphasize the necessity and the feasibility of the implementation of thermobaricity in lake models to ensure correct behaviour of the deep water renewal.
Keywords: Thermobaricity; Limnology; Deep Water Circulation; Cabbeling; Lake Shikotsu