Derivation of lake mixing and stratification indices from high-resolution lake buoy data

Authors

Jordan S. Read, Department of Civil and Environmental Engineering, University of Wisconsin–Madison
David P. Hamilton, Centre for Biodiversity and Ecology Research, University of Waikato
Ian D. Jones, Centre for Ecology and Hydrology, Lancaster Environment Centre
Kohji Muraoka, Centre for Biodiversity and Ecology Research, University of Waikato
Luke A. Winslow, Center for Limnology, University of Wisconsin–Madison
Ryan Kroiss, Center for Limnology, University of Wisconsin–Madison
Chin H. Wu, Department of Civil and Environmental Engineering, University of Wisconsin–Madison
Evelyn E. Gaiser, Department of Biological Sciences and Southeast Environmental Research Center, Florida International UniversityFollow

Abstract

Lake Analyzer is a numerical code coupled with supporting visualization tools for determining indices of mixing and stratification that are critical to the biogeochemical cycles of lakes and reservoirs. Stability indices, including Lake Number, Wedderburn Number, Schmidt Stability, and thermocline depth are calculated according to established literature definitions and returned to the user in a time series format. The program was created for the analysis of high-frequency data collected from instrumented lake buoys, in support of the emerging field of aquatic sensor network science. Available outputs for the Lake Analyzer program are: water temperature (error-checked and/or down-sampled), wind speed (error-checked and/or down-sampled), metalimnion extent (top and bottom), thermocline depth, friction velocity, Lake Number, Wedderburn Number, Schmidt Stability, mode-1 vertical seiche period, and Brunt-Väisälä buoyancy frequency. Secondary outputs for several of these indices delineate the parent thermocline depth (seasonal thermocline) from the shallower secondary or diurnal thermocline. Lake Analyzer provides a program suite and best practices for the comparison of mixing and stratification indices in lakes across gradients of climate, hydro-physiography, and time, and enables a more detailed understanding of the resulting biogeochemical transformations at different spatial and temporal scales.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Read, J., D. Hamilton, I. Jones, K. Muraoka, R. Kroiss, C. Wu, E.E. Gaiser. 2011. Derivation of lake mixing and stratification indices from high-resolution lake buoy data. Environmental Modelling and Software 26(11): 1325-1336.