Evaluation of Low-Cost, Automated Lake Ice Thickness Measurements

Abstract

Climate change is expected to decrease ice coverage and thickness globally while increasing the variability of ice coverage and thickness on midlatitude lakes. Ice thickness affects physical, biological, and chemical processes as well as safety conditions for scientists and the general public. Measurements of ice thickness that are both temporally frequent and spatially extensive remain a technical challenge. Here new observational methods using repurposed soil moisture sensors that facilitate high spatial–temporal sampling of ice thickness are field tested on Lake Mendota in Wisconsin during the winter 2015/16 season. Spatial variability in ice thickness was high, with differences of 10 cm of ice column thickness over 1.05 km of horizontal distance. When observational data were compared with manual measurements and model output from both the Freshwater Lake (FLake) model and General Lake Model (GLM), ice thickness from sensors matches manual measurements, whereas GLM and FLake results showed a thinner and thicker ice layer, respectively. The FLake-modeled ice column temperature effectively remained at 0°C, not matching observations. We also show that daily ice dynamics follows the expected linear function of ice thickness growth/melt, improving confidence in sensor accuracy under field conditions. We have demonstrated a new method that allows low-cost and high-frequency measurements of ice thickness, which will be needed both to advance winter limnology and to improve on-ice safety.

Integrating Perspectives to Understand Lake Ice Dynamics in a Changing World

“…For example, temperature moorings and meteorological instrumentation provide critical input and validation data for hydrodynamic models. Within‐ice temperature sensors can provide additional data for testing and validating ice growth and decay models (Reed et al, 2019; Whitaker et al, 2016). Other instruments such as ground‐penetrating radar (GPR) and under‐ice sonar are useful for direct measurements of snow and ice thickness (Brown & Duguay, 2011; Gunn et al, 2015).…”