2024-03-29T00:19:14Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/350622022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116Stratification of very deep, thermally stratified lakesVery deep, thermally stratified lakesBoehrer, BertramFukuyama, RyujiChikita, Kazuhisaphysical limnologystratificationdeep watermeromixisthermobaric effect452In 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.American Geophysical UnionJournal Articleapplication/pdfhttp://hdl.handle.net/2115/35062https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/35062/1/Boehrer-20080618.pdf0094-8276AA00657102Geophysical Research Letters3516L164052008-08enginfo:doi/10.1029/2008GL034519An edited version of this paper was published by AGU. Copyright 2008 American Geophysical Union.author