Abstract
This thesis present studies of the thermo- and hydrodynamics in large temperate lakes in spring, with special focus on the thermal bar. The thermal bar is defined as a zone of descending water with the temperature of maximum density. The character of the temperature distribution during spring is of importance as it affects the condition for vertical mixing, which in turn affect water quality and biological activity. The practical importance of the thermal bar is that it inhibits exchange of water between the on- and offshore regions. The objectives of this work are to determine the main mechanisms that govern the thermal bar progression, analyze the thermal structure and its development in large temperate lakes, and investigate the circulation associated with the thermal bar, with focus on the relative importance of density-induced currents compared to wind-driven currents. The investigation methods consist of field measurements, analysis of the water surface temperature structure by satellite data, and usage of analytical and numerical models. The thermal bar is initiated at the shore and moves towards the deeper parts of the lake as spring heating proceeds. The three main factors that determine the thermal bar progression are surface heat flux, bottom topography, and heat
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Citation Formats
Malm, J.
Thermal bar dynamics. Spring thermo- and hydrodynamics in large temperate lakes.
Sweden: N. p.,
1994.
Web.
Malm, J.
Thermal bar dynamics. Spring thermo- and hydrodynamics in large temperate lakes.
Sweden.
Malm, J.
1994.
"Thermal bar dynamics. Spring thermo- and hydrodynamics in large temperate lakes."
Sweden.
@misc{etde_10114524,
title = {Thermal bar dynamics. Spring thermo- and hydrodynamics in large temperate lakes}
author = {Malm, J}
abstractNote = {This thesis present studies of the thermo- and hydrodynamics in large temperate lakes in spring, with special focus on the thermal bar. The thermal bar is defined as a zone of descending water with the temperature of maximum density. The character of the temperature distribution during spring is of importance as it affects the condition for vertical mixing, which in turn affect water quality and biological activity. The practical importance of the thermal bar is that it inhibits exchange of water between the on- and offshore regions. The objectives of this work are to determine the main mechanisms that govern the thermal bar progression, analyze the thermal structure and its development in large temperate lakes, and investigate the circulation associated with the thermal bar, with focus on the relative importance of density-induced currents compared to wind-driven currents. The investigation methods consist of field measurements, analysis of the water surface temperature structure by satellite data, and usage of analytical and numerical models. The thermal bar is initiated at the shore and moves towards the deeper parts of the lake as spring heating proceeds. The three main factors that determine the thermal bar progression are surface heat flux, bottom topography, and heat transfer from the near-shore region to the thermal bar zone. The measured temperature distributions are in good agreement with other field observations during spring, with a stably stratified near-shore region on the shore side of the thermal bar, and a connectively mixed deep water region on the offshore side. The stable stratification may be destroyed by wind action during early spring. Still, the density-induced currents are of importance in a longer time perspective, especially when the thermal bar zone is characterized by large horizontal temperature gradients. 35 refs, 9 figs, 1 tab}
place = {Sweden}
year = {1994}
month = {Dec}
}
title = {Thermal bar dynamics. Spring thermo- and hydrodynamics in large temperate lakes}
author = {Malm, J}
abstractNote = {This thesis present studies of the thermo- and hydrodynamics in large temperate lakes in spring, with special focus on the thermal bar. The thermal bar is defined as a zone of descending water with the temperature of maximum density. The character of the temperature distribution during spring is of importance as it affects the condition for vertical mixing, which in turn affect water quality and biological activity. The practical importance of the thermal bar is that it inhibits exchange of water between the on- and offshore regions. The objectives of this work are to determine the main mechanisms that govern the thermal bar progression, analyze the thermal structure and its development in large temperate lakes, and investigate the circulation associated with the thermal bar, with focus on the relative importance of density-induced currents compared to wind-driven currents. The investigation methods consist of field measurements, analysis of the water surface temperature structure by satellite data, and usage of analytical and numerical models. The thermal bar is initiated at the shore and moves towards the deeper parts of the lake as spring heating proceeds. The three main factors that determine the thermal bar progression are surface heat flux, bottom topography, and heat transfer from the near-shore region to the thermal bar zone. The measured temperature distributions are in good agreement with other field observations during spring, with a stably stratified near-shore region on the shore side of the thermal bar, and a connectively mixed deep water region on the offshore side. The stable stratification may be destroyed by wind action during early spring. Still, the density-induced currents are of importance in a longer time perspective, especially when the thermal bar zone is characterized by large horizontal temperature gradients. 35 refs, 9 figs, 1 tab}
place = {Sweden}
year = {1994}
month = {Dec}
}