Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
doi:10.5194/hess-2016-262
© Author(s) 2016. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
26 Jul 2016
Review status
A revision of this discussion paper is under review for the journal Hydrology and Earth System Sciences (HESS).
Response of water temperatures and stratification to changing climate in three lakes with different morphometry
Madeline R. Magee and Chin H. Wu Department of Civil and Environmental Engineering, University of Wisconsin – Madison, Madison, WI 53706, USA
Abstract. Water temperatures in three morphometrically different lakes are simulated using a one-dimensional hydrodynamic lake model over the century (1911–2014) to elucidate the effects of increasing air temperature and decreasing wind speed on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes). During the study period, epilimnetic temperatures increased, hypolimnetic temperatures decreased, and the length of the stratified season increased for the study lakes due to earlier stratification onset and later fall overturn. Additionally, there was an abrupt change in epilimnion temperature after 1930 in both Lake Mendota and Lake Wingra, and three changes, after 1934, 1995, and 2008 for Fish Lake. There was a significant change in the slope of trend of stratification duration after 1940 in Lake Mendota and a significant change in trend after 1981 for Fish Lake. Schmidt stability showed a statistically significant increasing trend for both deep lakes, with the larger trend and greater variability in the larger surface area lake. Sensible heat flux in all three lakes increases over the simulation period while longwave heat flux decreases. The shallow study lake had a greater change in latent heat flux and net heat flux, illustrating the role of lake depth to surface heat fluxes. Sensible heat flux in all three lakes had similar timing of abrupt changes, but the magnitude of the change increased with increasing depth. Abrupt changes in latent heat flux appear to be independent of lake morphometry, indicating that the timing of change may be primarily driven by climate. Perturbing drivers showed that increasing air temperature and decreasing wind speed caused earlier stratification onset and later fall overturn. For hypolimnetic water temperature, however, increasing air temperature warmed bottom waters while decreasing wind speed cooled bottom waters, indicating that the change of hypolimnetic temperatures globally may be influenced by local changes in wind speed. Overall, lake depth impacts the presence of stratification and magnitude of Schmidt stability, while lake surface area drives differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates.

Citation: Magee, M. R. and Wu, C. H.: Response of water temperatures and stratification to changing climate in three lakes with different morphometry, Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-262, in review, 2016.
Madeline R. Magee and Chin H. Wu
Madeline R. Magee and Chin H. Wu
Madeline R. Magee and Chin H. Wu

Viewed

Total article views: 219 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
146 68 5 219 11 13

Views and downloads (calculated since 26 Jul 2016)

Cumulative views and downloads (calculated since 26 Jul 2016)

Saved

Discussed

Latest update: 23 Mar 2017
Publications Copernicus
Download
Short summary
Water temperatures and stratification in three morphometrically different lakes over the century are examined. It is found that surface temperatures increased, bottom temperatures decreased, and duration of the stratified increased. Abrupt changes in latent heat flux appear to be independent of morphometry, indicating that the timing of change is driven by climate. Increasing air temperature warmed bottom waters while decreasing wind speed cooled bottom waters, suggesting that the change of bott
Water temperatures and stratification in three morphometrically different lakes over the century...
Share