Author(s): Georgiy Kirillin; William Rizk; Matti Lepparanta
Linked Author(s): Matti Leppäranta, Georgiy Kirillin
Keywords: No Keywords
Abstract: Convection caused by solar radiation is the main driver for mixing under ice in spring and is the most energetic process in ice-covered lakes. It affects ice melting rate and has important ecological implications, in particular, by providing the vertical transport mechanism for nonmotile plankton species. In temperate lakes, convection depends strongly on the diurnal radiation cycle. We present the first data on the convective shear microstructure with the daytime variations resolved. In addition, for the first time the convection characteristics were achieved for the period immediately preceding the ice break-up, when fieldwork from the ice surface is not possible. The results validate the shear microstructure method for the under-ice convection in the absence of mean flow and provide the direct quantitative estimations of the convective mixing intensity. We outline the range of the convective variability within a day and its dependence on the amount of solar radiation penetrating the ice cover. The appropriate mixed layer scaling is discussed.
Year: 2012