A number of these properties have been described in publications, so we
shall only mention them in general outline. First of all there is the ability of the
ice sheet to record the direction of prevailing winds, which we can interpret on
the photographs from small snow ridges [1]. There is also the property of
fast-ice near the rivers which discharge into the sea to indicate the site of
submerged shoals, migrating annually under the influence of river drainage [1].
The scientific and practical value of both these properties can hardly be
overestimated.
We must also point out that it has become possible to describe the genetic
characteristics of sea-ice by the surface pattern which appears in the first half
of the melting process. In addition, the morphological elements typical of ice
and independent of the photo image pattern, but due only to its form and
tint on aerial photographs, can be used to characterise the microrelief of the
day surface of sea-ice. At the same time, the existence of three main form-
types of névés, established by interpretation of aerial photographs, enables us to
surmise the relief features of the ice bottom surface. This last circumstance
makes it possible to single out in the fast-ice, the areas with different thick
nesses of ice [2].
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conditions of the Arctic seas. This method requires a systematic survey of ice
conditions for the compilation of comparable ice charts. At first, such a survey
was carried out visually by aerial ice patrols but increasingly greater require
ments called for an addition to the data supplied by aerial ice patrols, and
eventually made Soviet oceanographers tackle the problem of aerial photo
graphic surveys in earnest.
The beginning of aerial photographic surveys of ice in our country dates
back to 1945 when a new method of combined vertical and oblique photo
graphs from an altitude of 450 metres [1] was employed for the first time. Later,
other process charts and technical facilities [4, 6, 7] were developed, and the
aerial survey of sea-ice became a regular feature in our investigations. It proved
to be very instrumental in the compilation of very accurate ice charts.
This paper does not enter into details as to the methods of aerial photogra
phic surveys and the technical facilities employed for the purpose. We have
also omitted certain particulars concerning the advantages in the quantitative
and qualitative estimation of sea-ice obtained from aerial photographs and
based on the wealth of information which they supply. This paper pursues
only one aim - i.e. - to show new natural interconnections between sea-ice and
the environment as well as new regularities observed at various stages during
which the sea-ice has been in existence.
Without the aid of aerial photographic surveys, these interconnections and
regularities were extremely difficult to detect, because the data of visual aerial
observations were distorted by the effect of the velocity of aircraft. It was only
the high informative ability of aerial photographs, preserving the instantaneous
picture of the state of ice for a long time, that made it possible to reveal the
manifestations of new properties inherent to sea-ice.
