Ice-covered lakes are isolated from the atmosphere, and light penetrating the ice is one of the main mechanisms to warm lake water during wintertime. Accurate quantification of under-ice light is therefore crucial for assessing biological activity and physical dynamics during the ice-covered season. At present, direct measurements of under-ice light are limited, mainly due to logistical difficulties during the winter season. Therefore, in practice, the fraction of light penetrating through the ice cover is estimated by an exponential decay described by the Beer-Lambert law through the ice, knowing the albedo, the thickness and composition of the ice cover (black ice, white ice and snow), and the light extinction coefficient of each layer. However, literature values for the light extinction coefficient are generally site-specific and rare, which poses limitations. In this work, we collected a dataset of light measurements both above and below ice, and total ice and snow thickness from 46 lakes in the Northern Hemisphere with 828 daily measurements (including 15 lakes and 628 measurements with ice quality information). Based on the Beer-Lambert law, we developed a Bayesian model for predicting under-ice light and incorporating a comprehensive uncertainty assessment, given the thickness of each layer and the above-ice light. The use of a large data set allows a stable estimation of the distribution of light extinction coefficients. Coupled with ice thickness models, it can be used to provide insights into future trends in light availability in lakes worldwide.

Authors:

Gaia Donini, University of Trento  (gaia.donini@unitn.it)

Claudio Agostinelli, University of Trento  (claudio.agostinelli@unitn.it)

Eric Anderson, Colorado School of Mines  (ejanderson@mines.edu)

Ilya Aslamov, Russian Academy of Sciences  (ilya_aslamov@bk.ru)

Joshua Culpepper, York University  (jculpepper@nevada.unr.edu)

Hilary Dugan, University of Wisconsin–Madison  (hdugan@wisc.edu)

Irina Fedorova, National Academy of Sciences of The Republic of Armenia  (umnichka@mail.ru)

Ellinor Jakobsson, Uppsala University  (ellinor.jakobsson@ebc.uu.se)

Georgiy Kirillin, Leibniz-Institute of Freshwater Ecology and Inland Fisheries  (georgiy.kirillin@igb-berlin.de)

Lesley Knoll, Miami University  (knolllb@miamioh.edu)

Matti Leppäranta, University of Helsinki  (matti.lepparanta@helsinki.fi)

Madeline Magee, Wisconsin Department of Natural Resources  (madeline.magee@wisconsin.gov)

Rebecca North, University of Missouri  (northr@missouri.edu)

Ulrike Obertegger, Fondazione Edmund Mach  (ulrike.obertegger@fmach.it)

Nikolay Palshin, Karelian Research Centre of RAS  (npalshin@mail.ru)

Nolan Pearce, Trent University  (nolanpearce@trentu.ca)

Jenna Robinson, Rensselaer Polytechnic Institute  (robinj8@rpi.edu)

Kirill Shchapov, University of Minnesota Duluth  (shcha001@d.umn.edu)

Kevin Vikström, Uppsala University  (kevin.vikstrom@ebc.uu.se)

Gesa Weyhenmeyer, Uppsala University  (gesa.weyhenmeyer@ebc.uu.se)

Marguerite Xenopoulos, Trent University  (mxenopoulos@trentu.ca)

Xiao Yang, Southern Methodist University  (xnayang@mail.smu.edu)

Roman Zdorovennov, Karelian Research Centre of RAS  (romga74@gmail.com)

Galina Zdorovennova, Karelian Research Centre of RAS  (zdorovennova@gmail.com)

Sebastiano Piccolroaz, University of Trento  (s.piccolroaz@unitn.it)