Geology Reference
In-Depth Information
sensing research applies laterally to research in other
ice‐related disciplines such as engineering, climatology,
and glaciology. However, judging from several recent
publications, it seems that researchers in these fields tend
to remain confined within the level of knowledge about
ice physics that they keep circulating since 1970s and
1980s. One of the reasons for this tendency is the fact
that those researchers usually come from different scien-
tific backgrounds. For example, ice‐related engineering
problems are dealt with by engineers trained mainly in
the broad fields of civil, mechanical, or aerospace engi-
neering to whom the ice is a “nuisance.” Glacier ice and
to some extent sea ice is studied mostly by the geogra-
phers trained in the vast aspects of geography but not
necessarily physics. None of these communities, except
for the physicists, treat snow and ice as extremely high
temperature materials.
Remote sensing of sea ice has been conducted by
researchers from a wide range of scientific background
that encompasses computer sciences, environmental
sciences, geography, and electrical and civil engineering.
One goal of this topic is to bring out some progress made
in the field of ice physics that could expand the scope of
knowledge of the researchers and operators in the differ-
ent aspects of sea ice and hopefully influence their work.
The topic is intended to reach out to a variety of sea ice
audiences who study different aspects of the ice phenom-
enon related to physics, remote sensing, mechanical
behavior, climatic impacts, operational monitoring, etc.
For many readers, it is not crucial to gain deep under-
standing of ice as a material. For that reason the authors
have tried to present the material in a simplified and
gradual manner whenever possible so the reader can gain
the amount of information that suits his/her purpose. To
facilitate this presentation approach, definitions are
introduced constantly with cross referencing, treatments
of both physics and remote sensing material start from
first principles, many illustrations are used, derivation of
commonly used equations is presented, many references
are provided, etc. In short the topic is intended to be of
educational value.
The topic places more focus on sea ice research and
applications achieved in Canada. A few Canadian institu-
tions have been involved in different aspects of sea ice
physics and remote sensing research and applications. The
National Research Council of Canada undertook research
into ice physics and mechanics to support shipping and
engineering operations in ice‐rich waters. The Canadian
Ice Service of Environment Canada (the federal depart-
ment of the environment) provides the most timely infor-
mation about ice in Canada's navigable waters. Canada
Centre for Remote Sensing (the government of Canada's
center of excellence for remote sensing and geodesy) has
conducted extensive research and science programs to
1.6. aBout tHe topic and its organization
This topic combines information on two aspects of sea
ice: physics and remote sensing. Research communities
from the two disciplines do not usually interact; in gen-
eral, the active members may not be aware of the details
about each other's realm of interest or work. When geo-
physicists and materials scientists embarked on intensive
studies of sea ice in the 1950s, they soon realized the need
for tools to monitor ice conditions at larger scales. The
scales of observations are certainly different, but micro-
structural features seen at the grain‐ or subgrain‐scale
level are also repeated at the floe‐scale and floe‐fragments
levels. Macroscopic images often look very similar to
space‐borne images. The intergranular activities like
shearing between the grains and subgrains are often
reflected in the interfloe behaviors like ridging, rafting,
and rubble formation. Similarly, intragranular processes
like dislocations pileups, cell formations, or intragranular
cracking activities appear to be similar to many deforma-
tion patterns seen at the large scales. The tools, airborne
and the space‐borne remote sensing, eventually became
available by the mid‐1970s. On the other hand, when the
remote sensing researchers started their work to retrieve
sea ice parameters from the observations, they too real-
ized the importance of knowledge more on the physics of
sea ice in order to support the interpretation of the data
and the retrieval of ice information. Today, it is common
to see basic information on ice physics cited in the litera-
ture of remote sensing, but it is not common to see the
opposite. This topic furnishes an opportunity for the two
research communities to meet and perhaps learn a bit
more about each other's work.
Knowledge about sea ice physics is relatively well estab-
lished, while knowledge about remote sensing of sea ice is
still in developing mode. The remote sensing information,
however, has an edge because considerable amount of
information has become widely available on the Internet.
This availability does not apply to the information on ice
physics. Unsurprisingly, at this time of information explo-
sion, if the required information is not readily available
on the Internet, the common notion is that it does not
exist! This topic is an attempt to restore a balance between
the two subjects in a single presentation, although the
vast areas of engineering physics of ice remained
untouched here. It provides only the basic physics of sea
ice for the ice remote sensing researchers to develop bet-
ter physical insight into the subject of their study. It also
provides a reasonable scope of applications of ice remote
sensing for the ice physicists and geophysicist to compre-
hend the potential and limitations of the remote sensing
applications.
The argument about the importance of a satisfactory
level of knowledge about sea ice physics for remote
