Structure and Properties of Lake Ice - Freezing of Lakes and the Evolution of their Ice Cover - page 56

Fig. 3.3 Ice crystal structure Baltic Sea landfast ice (left) and lake ice (right). Each connected
colour spot corresponds to one ice crystal; the scale on top is in millimeters. The top layer is fine-
grained snow-ice, and the lower layer is columnar-grained congelation ice. According to Kawamura
et al. (2002)

2

r cl T 0
q w L f D T 0

D G ¼ 16 p
3

r cl ð 3 : 1a Þ

r cl T 0
q w L f D T 0

r c ¼ 2 ð 3 : 1b Þ

T 0 where is the solid-

liquid equilibrium temperature (273.15 K at the standard atmospheric pressure), and
D T 0 ¼ T 0 T is the amount of supercooling. For pure water,

˃ cl is the surface energy of the crystal in contact with the liquid,

˃ cl =33mJm − 2 , the
amount of supercooling is 40 K, and r c = 1.35 nm is the critical radius of a crystal,
containing about 100 molecules.
In natural surface waters, with heterogeneous nucleation taking place on suspended
particles, the amount of necessary supercooling is largely reduced from the homogeneous
case. Assume that an n-faced prismatic ice crystal grows on a surface of a substrate.