The Ice. Stephen J. Pyne
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Название: The Ice
Автор: Stephen J. Pyne
Издательство: Ingram
Жанр: Журналы
Серия: Weyerhaueser Cycle of Fire
isbn: 9780295805238
isbn:
But the iceberg escapes this condition. The berg was accessible to traditions of representational art and, almost alone among Antarctic ices, it was painted and photographed by pre-modernists. It is easy to value the berg because one can contrast its ice mass to non-ice surroundings. Broken out of the ice field, the berg acquires new properties, new motions, new structures. It offers contrasts, often brilliant, with its new environs. It does not match ice with ice but ice with sky, sea, earth. Were the ice still embedded in the polar plateau or the ice shelf, the appearance of the berg would be far less dramatic; it would not even have an identity in any meaningful sense. But amidst the Southern Ocean—surrounded with chunks of glacial ice, pack-ice floes, ocean waves, storms, mixed clouds, changing skies, aquatic life—the berg acquires immediate esthetic appeal. There is even sound: the cries of birds, the slap of waves and whitecaps, the hissing of air bubbles rupturing from glacial ice. The berg breaks, at last, the enormous silence of The Ice.
So it is with the ice field of Antarctica. Were the Earth truly an ice planet, the Antarctic would hold little interest. It is the contrast of ice to Earth, and of Ice to Idea, that makes it fascinating. The whiteness of the berg would be oppressive—meaningless—without its surrounding environment of sea and civilization. The berg is the most revealing of Antarctic ices because, in departing the ice field, it is the least typical. It is the most accessible of Antarctic ices because, in its many contrasts, it is the most complex. The berg is rich in information and knowable; its appearance can be quickly appreciated and assimilated. In Antarctica, the complicated is easy, the simple baffling.
VANISHING POINT
The iceberg, much reduced, drifts and disintegrates.
As it nears the boundary of the convergence, it breaks and ablates rapidly. It spins ponderously in its sheath of meltwater. Those waters vanish into the bottom circulation of the world ocean and the ambient humidity of the global atmosphere. They are part of the hydrologic cycle, the final cycle The Ice will know. The berg has lived within a great series of vortices, a geophysical field shaped by ice. At their source is a profound stillness, as close as the Earth can get to a condition of absolute zero, a cold so intense as to seemingly halt all motion. Outward from this origin the ice accelerates, the cycles multiply. The Antarctic convergence is the final perimeter. Once the berg crosses that frontier it is outside the ice field and soon expires. Its disintegration is rapid and inevitable. Slowly it spins its final rotations. Its bobbing causes a patch of green ice within it to flash like a semaphore from a field of white, a bottle in a message. The berg blinks like a dying pulsar, then disappears.
For a while its particles fly free from the ice, like the tedious outward burst of a frozen big bang. But none will ever escape that influence entirely. And over geologic time some will return. Once again they will be reduced from complexity to simplicity, reshaped to unearthly minima, and drawn back into the great polar vortex—back to the ends of the world, back to the spiraling nebula of Ice that is Antarctica, sweeping everything within its field into the heart of an immense whiteness.
The Ice
| 1 | The Pack |
[The ship] came to the limits of the world, to the deep flowing
Oceanus … shrouded in mist and cloud.…
—Homer, The Odyssey, Book XI
I will not say it was impossible anywhere to get in among this Ice, but I will assert that the bare attempting of it would be a very dangerous enterprise and what I believe no man in my situation would have thought of. I whose ambition leads me not only farther than any other man has been before me, but as far as I think it possible for man to go, was not sorry at meeting with this interruption, as it in some measure relieved us from the dangers and hardships, inseparable with the Navigation of the Southern Polar regions.
—Capt. James Cook, Journals, Voyage of the Resolution and Adventure (1774)
PROGRADATION
They raft across a wine-dark sea, sometimes isolated, sometimes strung together, circling the continent like gears within a vast orrery of floating ice.
A veil of low cloud and grey fog, a stygian current of black sea, a mobile breakwater of white ice: these define the terrane of the pack and the oscillating perimeter of The Ice. The boundary is multiple. The cold core of the global atmosphere and the tangled vortex of the world ocean roughly coincide with the ice field of Greater Antarctica, creating a complex zone of mixing. The Ice is surrounded by a circumference of swirling storms, where Antarctic and subantarctic air masses mingle; by braided currents and fronts that mix Antarctic and subantarctic waters; by a shadow line that separates the varied calendar of temperate time from the two seasons of the polar day. That all of these zones approximately overlap accounts for the intensity of Antarctica’s isolation. Of these processes, sea ice is both a product and a producer. As the zones wax and wane with the seasons, the ice field grows and decays on a grand scale, and the pack becomes the effective boundary of the continent.
While the iceberg is the most interesting ice mass in Antarctica, the pack ice is the most interesting ice terrane. Its rapid life cycle, its explosive winter growth and catastrophic summer collapse, the infinite movements of its numberless floes, with their constant rupturing and resuturing, the volatility of its position as a solid-phase boundary between two fluid regimes, air and sea—all give the pack a collective dynamism and variety unparalleled among Antarctic ices. This is the most complex and active of Antarctic systems. In part, the pack reflects this vigor and reduces it. The floes form an ice membrane between air and sea, atmosphere and hydrosphere; between land and the air-sea matrix, Antarctica and the fluids that bind it to the Earth; between biosphere and cryosphere, life and an inorganic lithosphere. In this twilight zone between Earth and Ice are mixed sea and sky, sea and ice, sky and ice, sea ice and land ice, life and lithosphere. Even in their colors and geometry the black sea and white ice recapitulate the two polar seasons: the summer day and the winter night.
This intermingling, so characteristic of the pack and so different from what goes on in the rest of the ice field, leads not to more complexity but to less. As the pack matures, it reduces dramatically the interactions among its component systems, and the reductionism and solipsism of The Ice are boldly extended outward. The mingling of sea, sky, and ice makes this region among the cloudiest on Earth: a perennial fog hangs cloyingly over the pack; the scene is shrouded in a stormy grey twilight. The ragged front of the pack creates a geographic warp, an icescape where space expands and dissolves, where time slows and distorts. Around the ice field the floes orbit, waxing and waning with the seasonal tides: at times loose and free-floating in the circumpolar current, like ice fragments trapped within the rings of Saturn, and at times frozen more or less solid, slowly creaking around, their gyres like Aristotelian spheres of quintessential crystal. Only the power of the outside world reverses the trend to greater and greater simplicity and uniformity. For millennia, the pack was the commanding barrier not only to human travel but to human mind. One could reach The Ice only by passing through the pack.
Glaciology of the Pack
The progradation of the pack begins with the coming of the austral twilight. The sun circles low on the horizon, a cold white globe. As ambient temperatures fall below the freezing point of seawater, sea ice begins to form. Ice forms first in protected embayments along the coast, most rapidly in the protected seas that ring the continent. Some takes the form of congelation ice, which organizes surface crystals into a scaffolding; some takes the form of frazil ice, slushy clumps of ice crystals suspended within supercooled seawater. From their structured mixing the floe evolves, by a series of stages. More ice and snow are added. Metamorphism restructures the ice breccias that comprise the floe. What happens on the microscopic level is then repeated on a macroscopic level. Individual floes interact, form a matrix, accept СКАЧАТЬ