ИСТИНА

Thermal stratification and energy budget of lakes are known to change with climate change, which affect the local climate and the lake ecosystem. In this study, we used a parameterized one-dimensional lake model called LAKE (Stepanenko et al., 2016) in order to quantitatively evaluate a response of thermal regime of Lake Suwa, a shallow mid-latitude lake in Japan, to climate change. LAKE simulates the heat transfer within the lake with k-epsilon turbulence closure model and the heat exchange between the atmosphere and the lake based on Monin-Obukhov similarity theory. We measured meteorological data and turbulent fluxes with eddy covariance method on the lake shore, and water temperature profile in the center of the lake, which were used to parameterize the model. We simulated water temperature from 1990 to 2006 using the parameterized LAKE model and evaluate the model validity. Finally, the response of thermal regime of the lake to expected climate change was examined. The default model underestimated momentum fluxes due to an underestimation of roughness length. The Charnock constant was modified to reproduce calculated roughness length from observed momentum fluxes. After this modification, the model reproducibility of momentum fluxes improved by about 20%. Similarly, the scalar roughness lengths were parameterized. The parameterized model showed good agreement with data on seasonal and daily variations of water surface temperature and sensible and latent heat fluxes. The model also showed the improvement of the reproducibility of the bottom water temperature. However, the model slightly overestimated water surface temperature and in turn heat fluxes. The water temperature simulation for 1990-2006 showed good agreement with observed data regarding the seasonal and interannual variations, proving the validity of the model to examine the response to climate change. We will present results regarding the response of thermal regime to future climate change at the poster.