Relations Between Freezing and Climate Change in a Mountainous Lake

Journal of the Japanese Society of Physical Hydrology, Vol.2, no.1

pp.1-11

Chikita A., Kazuhisa,Oyagi, Hideo, Makino, Sho, Kanna, Naoya, Tone, Kenta､ Sakamoto, Hideyuki, Hata, Shuntaro, Ando, Takuto and Shirai, Yuko

Ice-covered conditions of Lake Kuttara, a mountainous lake in Hokkaido, were explored in four winters of 2013 – 2016. Following the Jan-March mean air temperature (-4.23 °C in 2013, -3.50 °C in 2014, -1.06°C in 2015 and -2.41 °C in 2016), the lake was completely ice-covered for 83 days, 52 days and 33 days in 2013, 2014 and 2016, respectively, but mostly open in 2015. One-dimensional model for simulating temporal change of ice thickness after complete ice cover was designed by considering the heat budget in three layers of snow, ice and water. Simulated ice thicknesses were very reasonable to observed ones in 2013 and 2014. For detecting a sensitivity of the numerical simulation, the ice thickness under condition of +0.28 °C in air temperature after a decade was calculated for 2013, 2014 and 2016. Calculated mean ice thicknesses were by 9.1 %, 57.0 % and 83.3 % smaller than the original ones in 2013, 2014 and 2016, respectively. The ice thinning thus prevails in relatively warm winter.