Physical CharacteristicsAntarctica is hard to describe. It’s so big, so extreme. To give you some idea, it is more than one and a half times the size of the United States, and almost completely covered in an icecap, averaging a mile thick.This mass of ice accounts for an estimated 70% of the world’s fresh water, but ironically, Antarctica is actually a desert with only a few inches of precipitaion per year over most of the continent. Katabatic winds can reach speeds of 190 miles per hour along the coast, and air temperatures have been recorded at an astounding -89°C (-128°F). Antarctica is described as the coldest, windiest, driest, and highest continent on earth. During the three months of Antarctic summer, the sun never sets. Conversely in winter, the sun never rises, air temperatures drop to -40°C, and the ocean freezes into a 3-meter thick slab of fast ice, effectively doubling the size of the continent. In summer, the famously dangerous waters of the Southern Ocean break up the massive slab of ice, turning it into a jigsaw puzzle of pack ice, which packs together and spreads apart with the wind and currents. The pack ice eventually melts, only to be replaced the next winter – one of the most dramatic physical seasonal events in the world. There is no way to fully appreciate the magnitude of the ice except to see it. Far south of the crashing 10-meter swells of the southern ocean, and long before the actual continent is visible on the southern horizon, a thin white band at the splitting of sea and sky defines the edge of the pack. It is otherworldly, a tableau of foreign textures and colors. The jigsaw puzzle of floating ice extends to the edge of the horizon in all directions, broken only by floating mountains of blue ice, sawing at the sky like jagged teeth. It is magnificent. The Ross Sea itself is two-thirds the size of the Gulf of Mexico. Its northern boundary is defined by an underwater extension of Antarctica’s continental shelf. The underlying shelf averages about 500 meters below the surface of the water, composed of banks and deep troughs. At the outer edge the shelf drops away abruptly into the deep ocean abyss, quickly reaching depths of 3000 meters. At the surface, the Ross Sea’s southern boundary is a wall of ice cliffs, 40 m high and 700 km long, known to mariners as the “Ross Barrier”. But the barrier is floating. Deep under the wall, the sea continues southward toward the continent. The Ross Ice Shelf is actually the edge of the continental ice cap, which flows off the continent in a massive ice river, and floats out over the southern Ross Sea, 400 meters thick. Like all the icebergs that calve off the imposing front, 90% of it is underwater. The cliffs only hint at the unimaginable ice-mass below. In total area the shelf is the size of France. The water of the Ross Sea is at most -1.5°C, just above the freezing point of salt water. Your hands burn and throb for hours after only a few minutes exposure. It would freeze most organisms solid. But it is filled with life... The Ross Sea Story
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