Location
Online (email amgrad@uwaterloo.ca for link)
Candidate
Leonard Korreshi | Applied Mathematics, University of Waterloo
Title
Data Analysis Exploring Winter Stratification and Cold Water Dynamics in Lake Superior
Abstract
Compared to the summer, winter limnology is often less considered for study due to the difficulty of field work and disinterest in the dynamics below the ice. Thermistor and ADCP data collected in Lake Superior through under-lake moorings placed by the Large Lakes Observatory in University of Minnesota-Duluth over 10 years work to change this. The data can be used to understand the processes underlying inverse stratification and turnover during winter. Novel ways of displaying and comparing the data are presented, with spaghetti plots, EOFs, and wavelet coherence used to characterize the temperature profiles over time. To understand the drivers of stratification, additional meteorological and solar radiation data is brought in to calculate heat flux and shear velocity at the lake surface. Over the course of the winter season, wind and atmospheric effects weaken until solar radiation dominates and radiatively driven convection (RDC) becomes the main input into the lake until the spring overturn. Considering all these phenomema together will help build a more coherent picture of the winter period in very large lakes overall.