Introduction - Freezing of Lakes and the Evolution of their Ice Cover - page 9

to the polar oceans. Much of the research history in lake ice tells of applications of earlier
results of sea ice and river ice research to lake environment. This is largely because lake
ice has less scienti cance. For the background

references, the status of sea ice physics is presented in Wadhams (2000), Weeks (2010)
and Lepp

c history due to the less practical signi

ranta (2011), and for river ice a good coverage is contained in Ashton (1986),
Ferrick and Prowse (2002) and Shen (2006).
Lake ice is a degree more simple as compared with sea ice and river ice. Lake ice cover
is mostly immobile, circulation in the water body beneath the ice cover is weak, and
freshwater lake ice is poor in impurities. But lakes with strong through

ä

ow may have
river ice type processes, ice structure in brackish and saline lakes is similar to sea ice, and
drift ice occurs in very large lakes. Our knowledge of ice in saline waters comes mainly
from marine research, and these results are to a large degree applicable for brackish and
saline lakes.
This topic, Freezing of lakes and the evolution of their ice cover, presents an up-to-date
(year 2014) status of knowledge of the physics of lake ice with applications. The focus is
in freshwater lakes, with river ice and sea ice results utilized where necessary. The role of
dissolved substances of the parent water is explained here on the basis of the results of
sea-ice research. A historical view is embedded with material from the more than
100 years long period in lake ice research. Earlier literature of the physics of ice-covered
lakes is quite sparse. The important earlier topics include Barnes (1928), Shumskii (1956),
Pivovarov (1973), Michel (1978), and Ashton (1986), and also the topic of Pounder
(1965) contains much general material on ice in natural waters. Pivovarov (1973) pre-
sented a scienti

fl

c monograph on freezing lakes and rivers with weight on the liquid water
body, while Ashton (1986) had a more engineering point of view on this topic [see also
Ashton (1980) for a condensed review paper on the topic]. More recent material is given
in the article collections by Vincent and Laybourn-Parry (2008), George (2009), and in the
reviews of Kirillin et al. (2012) and Shuter et al. (2012).
This chapter introduces the topic with a brief historical overview. Chapter 2 presents
lakes, their classi

cation, and the zones of ice-covered lakes. Ice formation and the
structure and properties of lake ice are treated in Chap. 3 , with ice impurities and ice mass
balance. Chapter 4 contains lake ice thermodynamics from the freezing of lakes to ice
melting, with thermodynamic models included. Lake ice mechanics is the topic of Chap. 5
with engineering questions such as ice forces and bearing capacity of ice. A section is
included on drift ice in large lakes. Glaciers and pro-glacial lakes are treated in Chap. 6 .
Quite exotic lakes are introduced, in particular lakes at the top and bottom of glaciers and
ice sheets. Chapter 7 focuses on the water body beneath lake ice cover with water balance,
strati cation, and circulation. Ecology of ice-covered lakes is treated in Chap. 8 , con-

sidering the limitations brought by ice cover and considering life inside the ice cover. Also
environmental and practical questions with lake ice are treated, and the chapter ends at
evaluating the climate change impact on lake ice seasons. Final closing words are written
in Chap. 9 , and the topic ends with references. Study problems with solutions are given as