open access

https://hdl.handle.net/2115/35062

Stratification of very deep, thermally stratified lakes

Very deep, thermally stratified lakes

英語

thermobaric effect

2008-08

American Geophysical Union

Geophysical Research Letters

35(16)

L16405

In very deep freshwater lakes, deep recirculation presents itself with remarkable differences to shallower lakes. We consider the stratification where density gradients are exclusively due to temperature differences. The annual circulation patterns are discussed for various climatic conditions. Very deep lakes do not necessarily produce full overturns during Tmd transition in autumn and spring. Peculiarities of the stratification are derived for cases, in which surface temperatures cross 4℃ during the annual cycle: Firstly, the asymmetry between autumn and spring circulation, secondly, the proximity of temperature to the Tmd profile, and thirdly, the isothermal deep water. We compare conceptual model results of horizontally homogeneous lakes with measurements in very deep caldera lakes in Japan (Lakes Ikeda, Tazawa, Toya, Kuttara and Shikotsu). Between oligomictic lakes and thermobarically stratified lakes, we have found lakes circulating reliably despite their enormous depth. We discuss susceptibility to climate variability supported by comparisons with single point measurements from the 1920s and 1930s.

学術雑誌論文

Accepted Manuscript

An edited version of this paper was published by AGU. Copyright 2008 American Geophysical Union.

0094-8276

AA00657102