Chlorofluorocarbon gases (CFCs) take six or seven years to move up to the stratosphere and the winds spread them all round the world.Extreme cold, a freezing vortex wind, frozen stratospheric clouds and 6-month darkness over Antarctica all provide ideal conditions for chlorine to break from the CFCs.The chlorine (and bromine) gases destroy the ozone during spring (Sept to Dec) and this is what causes the ozone hole.More detail:Chlorofluorocarbon gases (CFCs) and related halocarbon gases are the main cause of ozone depletion all over the world. CFCs released from Western countries take several years to reach the stratosphere where the ozone layer is. During that time winds spread them all over the world. In the presence of ultraviolet light these gases release chlorine and bromine atoms which destroy some of the ozone in the ozone layer. This is called ozone depletion. The ozone hole is a related but different phenomenon. The hole is Antarctica occurs in the spring (September to December). It begins with this overall ozone thinning, but it is assisted by the presence of polar stratospheric clouds (PS clouds). During the extreme cold of winter, with no sun for six months, polar winds create a vortex which traps and chills the air; the temperature is below -80 Celsius. The ice in these PS clouds provides surfaces for the chemical reactions that destroy the ozone. This needs light to kick-start the reactions.In spring the sun rises above the horizon and provides energy which starts the photochemical reactions. The clouds melt and the trapped compounds (chlorine and chlorine monoxide from the CFCs) are released. Ozone in the lower stratosphere is destroyed and the ozone hole appears.By the end of spring warmer December temperatures break up the vortex and destroy the PS clouds. Sunlight starts creating ozone again and the hole begins to repair.(A similar hole in the Arctic [but smaller because of warmer temperatures] occurs during spring.)
What is Antarctica known for?
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Antarctica
- Antarctica, fifth in size among the world’s continents.
- Its landmass is almost wholly covered by a vast ice sheet.
Antarctica has so much to offer, here are some of the things Antarctica is known for.
Meeting the Penguins
When you first lay eyes on these ever-anthropomorphized birds:, you’ll know you’ve arrived in the Antarctic. From the tiny tuxedo-clad Adélie and the bushy-browed macaroni, to the world’s largest penguin, the fabulously debonair emperor, the Antarctic offers a chance to see these unique creatures on their own turf: sea, ice and shore. Spot them shooting out of the water, tobogganing along the ice, or in cacophonous rookeries that are a sight to behold: squawking, gamboling birds, hatching, molting, and caring for their young
Amundsen-Scott South Pole Station
First reached just over 100 years ago by the valiant explorer Roald Amundsen during the Heroic Age of Antarctic exploration, the South Pole still embodies myth, hardship and glory. Today it is topped by a high-tech station: surrounded by cutting-edge astrophysical observation equipment (including a neutrino detector array buried approximately 1.9 km below the ice). To the visitor, a photo op with the flapping flags and globe-topped pole, is, indeed, a once-in-a-lifetime opportunity.
Cruising the Lemaire Channel
The sheer-sided Lemaire Channel: is a perennial favorite for photography buffs and naturalists alike. Under pale-pink skies, glaciers tumble slow-motion to the sea from the mountains overhead. Your Zodiac glides past a floe topped by basking Weddell seals, another crowded by a noisy group of gentoo penguins. Nearby, an enormous female leopard seal sleeps off a recent meal on the edge of this channel first sailed by de Gerlache in 1898. Two rounded peaks at Cape Renard overlook it all.
Cape Evans
Reaching Ross Island’s Cape Evans: isn’t easy – but then again, it never was. Dog skeletons bleach on the sand in the Antarctic sun, chiding memento mori of Captain Robert Scott’s death march from the Pole. Inside Scott’s hut from that ill-fated Terra Nova expedition a collection of sledging pennants, rustling pony harnesses and a sighing wind evoke the doomed men who left here with high hopes of reaching the pole. Explore the captain’s bunk room, and peer at the perfectly preserved provisions and photographic supplies.
Shackleton’s Hut
Step inside Ernest Shackleton’s Nimrod-expedition hut: at Cape Royds on Ross Island and enter an eerily preserved world from a century ago. Amazingly intact despite over 100 years of blasting Antarctic storms, the wooden house is surprisingly homey. Colored glass medicine bottles line shelves, a fur sleeping bag rests on one of the bunks and tins of food with unappetizing names (boiled mutton, lunch tongue, pea powder) are stacked on the floor, awaiting diners who will never return. Adélie penguins fill the cape now, breeding in summer.
Paradise Harbor
The pragmatic whalers who worked in the waters of the Antarctic Peninsula at the beginning of the 20th century were hardly sentimental. Yet they named this harbor Paradise:, obviously quite taken with the stunning icebergs and reflections of the surrounding mountains. Gentoos and shags call the area home, with the penguins nesting in the remains of Argentina's Brown Station. A climb up the hill here offers magnificent glacier views. If you’re lucky, perhaps you’ll even see one calving.
Grytviken, South Georgia
A tall granite headstone marking the last resting place of British explorer Ernest Shackleton, known to his loyal men as simply ‘the Boss,’ stands at the rear of the whalers’ cemetery at Grytviken:. This old whaling station is still strewn with evidence of its past industry, and its South Georgia Museum gives insight into whaling life, as well as into South Georgia’s history and wildlife. Meanwhile, seals wriggle outside the station’s quaint, white-clapboard whalers’ church.
Deception Island
Deceptive in more ways than one, with its secret harbor, slopes of ash-covered snow, and hidden chinstrap penguin rookery at Baily Head, Deception Island: offers the rare opportunity to sail inside a volcano. Now classified as having ‘a significant volcanic risk,’ Deception remains a favorite for the industrial archaeology of its abandoned whaling station, half-destroyed by an eruption-induced mudflow and flood. Some will stop for a quick dip in the island’s heated geothermal currents.
Antarctic Museum at Port Lockroy
Each year, tens of thousands of visitors flock to Britain’s beautifully restored Bransfield House:, the main building of Base A, built at Port Lockroy during WWII. Not only does it offer the chance to spend up big at the well-stocked souvenir shop and to mail postcards at the busy post office, the museum’s old wooden skis, clandestine 1944 radio transmitter and wind-up HMV gramophone are evocative artifacts of the explorers who once lived for years at this wilderness outpost.
Charlotte Bay and Cuverville Island
Ah, how do you choose a favorite among the Antarctic Peninsula’s many gorgeous bays and inlets? Charlotte Bay: is certainly a contender…like Paradise Harbor, it can become studded with recently calved icebergs, reflected on the smooth sea surface. Many cruises pop in for a look, and test everyone’s supply of film or the size of their cameras’ memory cards. Nearby Cuverville Island is home to one of the largest gentoo rookeries on the Ice; several thousand pairs share their exquisite views with you.
Whale Encounters
One of the major pay-offs of the long passage across the Southern Ocean is the chance to spot migrating whales: circulating through krill-rich waters. Once nearer to land calling it whale-watching , if you’re in a Zodiac, doesn’t do it justice: you could be close enough to get a ‘whale bath.' The whale exhales with a startlingly loud ‘fffffffffffffff!’ right next to your boat, leaving you bathed in fish-scented mist. Near the ice edge, look for orcas hunting in pods.
Cape Denison
Douglas Mawson’s Australasian Antarctic Expedition didn’t realize when it set up its base in 1911 at East Antarctica’s Commonwealth Bay, near Cape Denison:, that fierce gravity-driven winds called katabatics make the place one of the windiest on Earth. Mawson later gave it the memorable moniker ‘the home of the blizzard.’ Even today, roaring winds that can top 160km/h may make getting ashore here impossible. But if you make it, you’ll find the windblown huts of these explorers, clinging tenaciously to the land.
Kayaking
The icy waters of the Antarctic Peninsula certainly number among the world’s most extraordinary paddles. Imagine your blades cutting the clear surface of the subzero waters as you navigate between towering icebergs and brilliantly hued ice formations. Seals may zip through the water beneath you, and penguins congregate on the shore after a quick dip in the sea. Seabirds circle overhead from their clifftop nests, and you are surrounded by it all. There are numerous cruises: that make kayaking possible.
McMurdo Station
Affectionately called Mac Town, Antarctica’s largest base:, operated by the US, is the central hub for many transiting to the interior. As such, its rough-and-tumble array of buildings can seem like an international adult summer camp. Enormous C-5 cargo planes occasionally land on the sea-ice runway, but usually the base is simply a hive of small aircraft and snowmobiles, as scientists come and go from base camps and the central science buildings. Visitors can’t help but pick up the infectious excitement of science in action.
Ross Ice Shelf
This towering sheet of ice, rising up from the Ross Sea, was the daunting barrier to many an Antarctic explorer. In fact, the Ross Ice Shelf: was formerly known simply as the Barrier, even though its thinnest part – a mere 100m thick – faced the sea. Inland, where the glaciers meet it, the slab can be as much as 1000m thick. The whole floating ice shelf is an astounding 520,000 sq km and was on the routes taken by both Amundsen and Scott to the South Pole.
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