Introduction - Sea Ice: Physics and Remote Sensing - page 10

developed sea ice, or siku , and rubbles, or ivuniit , near the
shoreline for the first time in his life. A few examples of
sea ice names in Inuktitut are given below.
Qinu The darker frazil or grease ice, seen during the
very beginning of winter, is known as qinu . No specific
distinctions are made between frazil ice and grease ice. In
general, the frazil refers to the stage when thin and tiny
plates or needles of ice are suspended loosely in the water.
Grease ice refers to the stage when the frazil crystals have
coagulated sufficiently to form a soupy or oily layer on
the surface.
Sikuaq As the ice grows thick enough to support a per-
son to walk on it, the name is changed from qinu to sikuaq .
Ice thickness is around 80 mm or more. This stage and up
to a thickness of 0.30 m, is termed as “young” ice accord-
ing to the World Meteorological Organization (WMO).
Tuvaq Ice in the open waters forms first around the
shorelines. If it continues to stay attached with the
land and continues to grow, then it is called, tuvaq ,
which is equivalent to land‐fast ice according to WMO
terminology.
Sinaaq One has to approach the edges of land‐fast or
tuvaq ice extremely carefully. The edges may crack and,
therefore, always very unsafe to walk. The children will
never be allowed to play and go close to the sinaaq .
Siku When the sea ice cover is sufficiently thick to sup-
port a group of people, it is called siku . This term is
equivalent to the WMO term First Year , which is assigned
to ice with thickness greater than 0.30 m.
Ivuniit During travel on the siku , or even going from the
shore to level ice, often ridges or rubbles of ice are encoun-
tered. They are caused by winds and/or currents or tidal
waves. These obstructions are named ivuniit .
Qavvaq Old, salt‐free white or translucent sea ice is
called as qavvaq or equivalent to MultiYear ice.
When an ice cover is thin, a small variation in thick-
ness results in large variations on the load it can carry,
especially for sea ice. Moreover, relatively larger varia-
tions in ice thickness occur during the early periods of
winter when the ice cover is thin. Most drowning or
break‐through accidents occur when the ice is thin or
not sufficiently thick to carry the load placed on the ice
covers. In reality the introduction of snowmobiles has
significantly increased range (and speed) of activities
among the young Inuits, but also, unfortunately, it
increased injuries and deaths, including ice‐related
drownings. Consequently, efforts in rescue operations
have become very challenging [ Lifesaving Society , 1998].
Anyway, as pointed out and illustrated earlier in
Figure 1.2, it is not easy to sample thin sea ice, such as
qinu or sikuaq , for metallurgical investigations. But one
does not require an icebreaker either to collect samples
of thin sea ice. The main problem is the fact that most ice
scientists living in areas remote from the Arctic and the

Antarctic sea ice are neither familiar with the bearing
capacities of newly grown sea ice in nature nor are they
equipped (mentally and physically) to go over thin ice.
Above all, unless one lives in the areas of interest and is
familiar to the formation of ice, year after years it is
impossible to know the characteristics of the ice cover,
particularly its thickness variability a few days after
the freeze‐up. Floating young sea ice cover, of thick-
ness < 0.01 m, imposes severe physical limitations on field
measurements and sampling. Prior to 1977, therefore,
very little effort had been made to examine young (Y) sea
ice as compared to numerous field investigations carried
out on mature first‐year (FY) sea ice. For that reason,
most of the early studies on the initial growth of saline
ice came from laboratory investigations.
Realizing the practical limitations—strategically, finan-
cially, as well as for the knowledge base—the author
(Nirmal Sinha) decided to work closely with the local
inhabitants of the Baffin Island. The goal was to tap and
learn from Inuit knowledge about sea ice. No question,
the Inuit elders were the experts on sea ice. Due to their
hunting experience on sea ice in certain localities for
many years and their long‐term observations on ice cov-
ers, they have developed profound and rich understand-
ings of the marine environment. Toward the end of 1976,
an opportunity came to him in Pond Inlet to build long‐
term relationships with the local residents. Although the
locals were the experts of ice, they never witnessed the
inner beauty of ice crystals that can be seen in thin sec-
tions of ice under polarized light. Using his home‐made
portable polariscope, the author introduced the Inuit
elders, the young, and the children to the wonderful world
of colors of ice crystals. Almost instantaneously he devel-
oped loving relationships of the local people. In fact, they
were bringing their ice samples, including pieces from an
iceberg grounded in Eclipse Sound. The bonds resulted
in conducting the long‐term studies on annual sea ice in
Eclipse Sound, described in Sinha and Nakawo [1981],
Nakawo and Sinha [1981, 1984], and Sinha [1983a].
A deep knowledge on the growth and distribution of ice
thickness in areas of oceans close to human settlements
helps in assessing wide ranging characteristics of ice, its
bearing capacity, and other engineering properties of
annual ice elsewhere, including pack ice.
Microstructurally, sea ice is significantly different from
freshwater river and lakes ice. It is also different from
other floating ice types of land origin such as icebergs or
land‐attached ice shelves and floating ice islands. The lat-
ter forms have significantly larger volume than sea ice
and therefore can easily be distinguished even if they are
surrounded by sea ice. Icebergs and ice islands protrude a
few meters above sea level. About 90% of all icebergs
encountered in Canadian waters are calved from the
glaciers of western Greenland. The annually observed