Author(s): Kunio Shirasawa; Matti Lepparanta; Toshiyuki Kawamura; Masao Ishikawa; Toru Takatsuka
Linked Author(s): Matti Leppäranta
Keywords: Heat flux from water; Floating ice; Growth; Melting; Measurements
Abstract: Ice in natural waters grows and decays as forced by the fluxes through the upper and lower boundaries. In particular, the flux at the lower boundary – i. e. the heat flux from the liquid water body into the bottom of the ice sheet – is not very well known quantity. This question is approached by measurements and mathematical modelling. The data are from Saroma-ko lagoon, a saline lake on the northern coast of Hokkaido, and Lake Paajarvi, a fresh water basin in southern Finland. Three-dimensional current velocity, temperature and salinity were measured at a fixed depth, and the resulting heat flux was normally 5–10 W/m2 in both basins, a bit more in Saroma. But even in Lake Paajavi, which is a rather quiet water body in wintertime (total ice coverage with very weak currents) the heat flux from the water is important in the heat budget of the ice sheet. A three-layer (snow/snow-ice/congelation ice) model is used to examine the evolution of ice thickness and temperature.
Year: 2006