JaLCDOI 10.18926/fest/11615
FullText URL 001_077_089.pdf
Author Okubo, Kenji| Morikawa, Hiroshi| Kimoto, Takashi| Tanaka, Yuji|
Abstract Thermal 'staircase', a layer of constant temperature between the sheets of the steep gradients, was formed in the seasonal thermocline, which was 2.5 m above the bottom at a point of 18 m deep on the boundary slope in Lake Biwa. Following a sediment resuspension event when a moderate onshore wind blew, bed materials should be suspended up to the thermocline, then settled down forming a staircase above the turbid intrusion. Comparing the observed downward hear flux with the settling flux of sediment, it was found that double-diffusive convection would play an important role on the formation of the whole structure consisting of the staircase and turbid intrusion along with chemical anomalies and dense population of phytoplankters, which were fed by nutrients supplied from the bottom sediment under a typical condition of drought. Laboratory experiments were conducted to demonstrate the thermal and sediment processes in the stratified lake. Resuspension process due to surface and internal waves was examined using a tank with a sloping bottom, while the settling process was investigated by using a deep, diffusive tank. Formative process and scales of the staircase and intrusion were discussed relating with the intensity of resuspension and the buoyancy fluxes.
Publication Title 岡山大学環境理工学部研究報告
Published Date 1996-03
Volume volume1
Issue issue1
Start Page 77
End Page 89
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313571