TY JOUR TI Small Lakes Mixing by Surface Cooling: Efficiency Estimates KW mixing efficiency KW surface cooling KW external forcing KW background potential energy KW small lakes JO Russian Journal of Earth Sciences AU Bogdanov, S.R. AU Efremova, T.V. AU Palshin, N.I. AU Zdorovennov, R.E. PY 2026 IS 26 PB Geophysical Center of the Russian Academy of Sciences