Sea ice

“ Along the shore the massive ice was still unbroken for miles out; but where the currents and tides and storms had begun to vanquish it, and the steel blue waves were eating into it hour by hour beneath the growing sunlight, there the life of the north was gathering. Sea-birds clamoured, and mated, and dived, and flew in circles, or settled in flickering gray and white masses on every jutting promontory of black rock. Along the blue-white ice-edge seals basked and barked, their soft eyes keeping incessant watch against the perils that always lurked about them. ”

“ In a large circle surrounding the ship, the surface of the pack was everywhere heaving up into a ring of rugged mountains high above the level of the sea! Huge masses of ice, large as ocean liners, pitched and rolled on the crests, while reverberating from all about came a shrieking and a screeching from the [Pg 161] tumbling ice that froze the very marrow in our bones. ”

“ Old sea ice may also attain a thickness of over 4 meters in this manner, or when summer melt water from its surface or from snow cover runs off into the sea and refreezes under the ice where the seawater temperature is below the freezing point of the fresher melt water. The growth of sea ice is dependent upon a number of meteorological and oceanographic parameters. Such parameters include air temperature, initial ice thickness, snow depth, wind speed, seawater salinity and density, and the specific heats of sea ice and seawater. ”

“ In the Antarctic Regions almost all the ice floating in the sea, whether land or sea ice, is covered at sea-level with a light wash of yellowish brown or yellow ochre. The bergs are coloured by it as well as the pack ice, where the ice is lapped by the sea. When a ship charges against a piece of one-year pack ice, the ice is easily broken and often breaks not only vertically, but horizontally. ”

“ Sea Ice.—The freezing-point of sea-water is lower as the salinity increases and normal sea-water of 35 per mille salinity freezes at 28.6° F. Experience shows that sea-water can be cooled considerably below the freezing-point without freezing if there is no ice or snow in contact with it. Freezing takes place by the formation of pure ice in flat crystalline plates of the hexagonal system, which form in perpendicular planes and unite in bundles to form grains so that a thick covering of ice exhibits a fibrous structure. It is only the water that freezes ”

“ We can well enter into the disappointment of those who expected to have found the long-talked-of open Polar Sea, instead of which ice, evidently of great age and thickness, the accumulation, it might be, of centuries, and resembling rather low floating icebergs massed together, than the ordinary appearance of salt-water. ”

“ In the polar regions, both north and south, when the sea is frozen, there always appears between the fast ice, which is the ice- 47 - attached to the land, and the sea ice, a crack which is due to the sea ice moving up and down with the rise and fall of the tide. ”

“ The origin of the shelf ice is believed to be a sea-ice which because not easily detached at the time of the spring “break-up” is thickened in succeeding seasons chiefly by the deposition of precipitated and drifted snow upon its surface, so that it is bowed down under the weight and sunk to greater and greater depths in the water. To some extent, also, it is fed upon its inner margin by overflow of glacier ice from the inland ice masses. ”

“ At length we managed to gain their attention, and were informed that, as soon as the wind should blow strong from the land, the ice might be expected to remove from the shore, so as to open a passage for boats, and that it would remain in the offing until the reappearance of the stars. "Further to the westward," they continued, "the ice often adheres to the land throughout the summer; and when it does break away, it is carried but a short distance to seaward, and is brought back whenever a strong wind blows on the coast. ”

“ About five o'clock in the afternoon, we had sight of more than thirty large islands of ice a-head, and perceived a strong white reflexion from the sky over the horizon. Soon after we passed through vast quantities of broken ice, which looked honey-combed and spungy, and of a dirty colour. This continually thickened about us, so that the sea became very smooth, though the wind was fresh as before. An immense field of solid ice extended beyond it to the south, as far as the eye could reach from the mast-head. ”

“ When sea ice is observed, the concentration, thickness, and position of the leading edge should be reported. The size, position, and, if observed, rate and direction of drift, along with the local weather and sea surface temperature, should be reported when icebergs, bergy bits, or growlers are encountered. ”

“ These pieces or masses of ice are pushed towards the shore, and there the ice first begins to make a firm covering over the sea.
‘But the ice on the sea is never smooth or even, like the ice on a pond or on a river; it is rough, and large pieces are heaped together, and large cracks are often made in the ice by the wind and the waves moving it, which makes it dangerous to drive or even walk a long distance over the Frozen Sea.’
‘Can people drive over the sea? ”

“ Already thin ice had formed on the surface of the water and, although each swell coming into the Welcome broke the newly formed ice with a curious crackling sound, fresh ice formed almost as rapidly as it was destroyed, and the upended little cakes were congealing in a jagged, hummocky surface that bade fair to imprison the waves very soon and lock them fast for many months. ”

“ Fresh-water-ice of the sailors is distinguished by its black appearance when floating in small pieces in the sea, and by its transparency when removed into the air. Fresh-water-ice is fragile, but hard; the edges of a fractured part are frequently so keen as to inflict a wound like glass. The most transparent pieces are capable of concentrating the rays of the sun, so as to produce a considerable intensity of heat. ”

“ The upper layer of this first surface of ice being elevated above the surface of the sea, will receive all the fresh water which falls from the atmosphere in the form of snow, sleet, rain or dew, by the successive congelation of which, the largest fields of ice may at length be formed.
It is a matter of little consequence to a navigator, whence the ice which supplies him with fresh water is produced. ”

“ In high northern or southern latitudes, solid clear ice melted affords good fresh water, the first runnings being thrown away as contaminated by adhering sea water. White cellular ice is quite unfit for the purpose, being strongly impregnated with salt. In future articles of our work, several opportunities will occur in which these two expedients for supplying ships with fresh water will be amply detailed. ”

“ It can be seen that this ice is much more plastic than fresh-water ice. Fresh-water ice is relatively brittle, even in thin layers. Fresh-water ice, of the thickness of about 21⁄2 or 3 inches, will bear the weight of a man, but a child's foot would sink through sea ice of similar thickness, as if going through a layer of tough glue. ”

“ While it is melting it takes all the heat available and so preserves the fresh-water ice, which melts after all the salt-water ice is gone. In old hummocky ice this process of purification has been going on intermittently whenever the weather was warm enough. I trust I have made these matters plain, but it is impossible by words to give a true idea of the marvellous colour and beauty of the ice in polar seas, or of its irresistible power when driven hither and thither by sea and wind. There can be no more terrific experience than a storm in a living polar pack. ”

“ The snow is now melted, and the blue sea-ice lies bare, scarcely tinged with red by the setting sun. Even the long winter night possesses its artistic charm from the midday arch of light, or the moon, which changes the channels beneath into rivers of silver. ”

“ The spreading ice-sheets having covered the land are able to flow into the surrounding seas, where their outer edges become detached and form icebergs, which float out to sea, and so scatter over the adjoining oceans. ”

“ The approximation of several fields of ice of different magnitudes, produces a very singular phenomenon. The smaller of these masses are forced out of the water, and thrown on the larger ones, until at length an aggregate is formed of a tremendous hight. These accumulated bodies of ice float in the sea like so many rugged mountains, and are continually increased in hight by the freezing of the spray of the sea, and the melting and then freezing of the snow which falls on them. ”

“ But, as things stand, the stock of ice at the poles never gets melted away in the existing northern or southern summer; fresh ice accumulates on top of the old mass with each winter; prevailing winds, blowing over this ice, chill regions lying much farther toward the tropics; icebergs detach themselves and float off, thus lowering the temperature of the sea in the middle zones; arctic or antarctic currents spread round the coasts and absorb the solar heat in enormous quantities. ”

“ During nearly two-thirds of the year the arctic regions are under the absolute dominion of winter; and for many weeks of that bitter season they are shrouded with the mantle of a dark, sunless night. The entire ocean is locked in the embrace of a covering of ice many feet thick, so that its liquid aspect is thoroughly removed; and, owing to ice-masses scattered over its surface, together with mounds of drifted snow, it bears a much stronger resemblance to the land than to the sea. ”

“ Next day, thanks to a falling thermometer, the ice had thickened, and the floes were compacted once more into a solid mass. Some of these floes, scattered here and there like gaunt icy islands in a sea of ice, were very big, with noticeable hummocks uprearing from the main mass. As a strong southerly wind was blowing, which was favourable to our purpose, we got busy and set topsail and staysail. Seen from outboard we must have looked much more like an ice-yacht than a sea-going ship, I fancy; but under the weight of this canvas we edged a very slow and very difficult way to the north. ”

“ As winter sets in within the Arctic Circle, the sea which flows between the northern coasts of Europe, Asia, and America becomes covered with ice to the shores, thus forming an enormous field of ice some two thousand miles across. This, lying on the surface of the water, often having a thickness of from thirty to fifty feet, checks, but cannot control the tides. The ebb, on one hand, leaves vast tracks of ice, previously afloat, straining on the ground, cracking so as to form enormous fissures and weakening the surface resistance. ”

“ Bearing these facts in mind, the reader will perceive that it is the surface-water only which ever reaches so low a temperature that it is changed to ice; and he will also perceive that when the wind moves the surface-water, the particles which have become chilled by contact with the air mingle in the rolling waves with the warm waters beneath, and hence that ice can only form in sheltered places or where the water of some bay is so shoal and the current so slack that it becomes chilled to the very bottom, or where the air over the sea is uniformly calm. ”

“ During the short but hot summer of the arctic regions, the immense masses of ice formed in winter are by no means cleared away. A great part of the heat of early summer (there is no season there that merits the name of spring) is spent in breaking up the solid crust of ice on the sea, a large proportion of which is carried south by the currents that flow to the equator, and melted long before they reach the temperate zones. ”

“ All young ice, such as bay-ice and light-ice, which form a considerable part of drift and pack-ice in general, is considered by Greenland sailors salt-water-ice; while fields, floes, bergs, and heavy-ice, chiefly consist of fresh-water-ice. Brash-ice likewise affords fine specimens of the latter, which, when taken out of the sea, are always found crowded on the surface with sharp points and conchoidal excavations. ”

“ ALL through the latter part of the winter the seal-hunters, who are out every day tending their nets, along the shore from Cape Smyth to Point Barrow, have been watching and studying the ice. Running along nearly parallel to the shore and about a thousand yards off, is a bar on which the water is not more than two or three fathoms deep. On this the heavy pack-ice, coming in with the autumn gales, usually grounds, piling itself up into a wall of rugged masses of ice, while inshore the sea freezes over smooth and level. ”

“ Field ice is frozen sea-water floating in a looser form than pack ice, covering large areas of the Polar seas, broken up into large pieces, driven together by current and wind, thus forming an almost continuous sheet of ice.
All these forms of ice masses are dangerous to shipping, and the ocean routes were mapped out so that vessels might be able to steer clear of them. As a matter of fact, although icebergs and field ice had been seen as far south before, it was many years since field ice had been observed so far south as at the time of the Titanic disaster. ”

“ Gradually the swell increased, and rolled along more swiftly, becoming in fact a very heavy regular sea, rather than a swell. The ice often lay so closely packed that we could hardly force ahead, although the fair wind had again freshened up. Much heavy hummocky ice and large berg-pieces lay dispersed through the pack ”

“ As it is not likely that any portion of the waters of the sea have been absorbed by the earth during the late epochs in the world’s history, therefore the ocean waters have not diminished except during cold periods, when the water evaporated from the sea was converted into ice, and, eventually, again returned to the sea. ”