Fact Sheet #20 : Antarctica Glossary

ablation - The removal of material from a glacier, melting, evaporation, or calving (bits dropping off the end into the sea to form icebergs). Opposite of accumulation.

ablation zone - That portion of a glacier where more material is lost (by melting or evaporation) than gained by snowfall.

abyssal plain - The deep ocean plain, a relatively flat part of the ocean floor lying at depths between 3500 meters (11,480 feet / 2.2 miles down) and greater than 6000 meters (19,680 feet / 3.7 miles down). This region is dark, cold (and very gloomy) subject to little or very slow water movements and very stable.

accumulation - The addition of material to glaciers, snow, rain, material blown by wind, and avalanches. Opposite of ablation.

accumulation zone - The region of the glacier where mass is only added (as snow or rain), no mass is lost. Usually this area is near the origin of the glacier at higher altitudes.

albedo - How reflective a surface is. High albedo means that much of the incoming radiation is reflected (for example snow and ice); low albedo means that much of the incoming radiation is absorbed (for example water).

algae - A plant group that compose the majority or all of the phytoplankton in bodies of water, mostly unicellular though there are multicellular forms such as kelp. Algae can form lichens in a symbiotic relationship with fungi.

Antarctic Bottom Water - The coldest and densest water mass in the global oceans. Formed in particular places on the Antarctic continental shelf such as Weddell Sea and Ross Sea when surface water cools and becomes more dense and so sinks to the ocean floor. Once formed it tends to flow northwards hugging the seafloor. It can be traced into many ocean basins, including parts of the North Atlantic Ocean.

Antarctic Circumpolar Trough - An atmospheric feature located between 60°S and 65°S. A zone of low pressure that causes variable winds moving from west to east and responsible for the "Screaming sixties" as known to seamen.

Antarctic Convergence (Polar Front) - A surface boundary where which the colder, north flowing Antarctic Surface Waters sink beneath warmer circulating waters. This marks a change in the oceans surface temperature and also chemical composition. North of the convergence, the area is known as the sub-Antarctic.

arid - Very dry. An area with little rain or precipitation of any kind (snow, hail, sleet etc.) usually less than 25 centimetres (10 inches) of annual rainfall, Antarctica is largely classed as arid.

arthropod - A group of invertebrates with hard exoskeletons and jointed limbs such as insects, spiders, and crustaceans (shrimps, crabs, lobsters).

Quest For The South Magnetic Pole

atmosphere - The gases that surround a planet. Earth's atmosphere consists of about 20% oxygen and 79% nitrogen with smaller amounts of other gases. "Atmosphere" is also used as a unit for the measurement of pressure. One atmosphere equals 14.7 pounds per square inch being the pressure due to the mass of the gases acting on the earth at sea level.

atmospheric circulation - Movement within the atmosphere, winds and air currents, caused by differences in pressure from one region to another. Air moves from a region of high pressure where it is "piled up" to "thinner" areas of low pressure.

atmospheric pressure - The amount of pressure exerted by the atmosphere at a given point (force per unit area). Essentially the effect of the mass of the air above a particular point being pulled down by gravity

atmospheric sciences - The study of the atmosphere, of the envelope of gases that surround the Earth. Atmospheric science include meteorology and climatology.

aurora - The display of "dancing" light patterns seen in areas of high latitudes - nearer the poles. Auroras are caused by magnetic storms from the sun releasing huge amounts of energy. The energy travels toward the Earth as an ionic cloud. On reaching the earth, the cloud "blows" over the poles and interacts with Earth's magnetic field. The ions interact with the ionosphere energize oxygen and nitrogen molecules which causes them to emit light.

Anything in the northern hemisphere is referred to as "Boreal", in the southern hemisphere as "Austral", hence Aurora Borealis in the north and Aurora Australis in the south.

avalanche - A mass of snow and/or ice detached from where it rested and slipping down a slope.

axis - An imaginary line through the centre of the Earth, around which the planet rotates.

Bbacteria - A group of acellular microscopic organisms, bacteria are found everywhere. Different types may be involved in the decomposition of organic matter, in making food by photosynthesis, in the guts of all multicellular organisms, in the deepest ocean and in Antarctica, even living inside rocks as protection from the elements.

Beaufort scale - A way of measuring the strength of the wind given as a number or "force":

Beaufort wind scaleWind force

Description Speed mph Specifications for use on land

Specifications for use at sea

0 Calm 0 - 1 mph Smoke rises vertically Sea like a mirror1 Light air 1 - 3 mph Direction of wind shown

by smoke drift, but not by wind vanes.

Ripples with the appearance of scales are formed, but without foam

crests.2 Light breeze 4 - 8 mph Wind felt on face,

leaves rustle, ordinary vanes moved by wind.

Small wavelets, still short, but more

pronounced. Crests have

a glassy appearance and do not break.

3 gentle breeze 9 - 13 mph Leaves and small twigs in constant motion,

wind extends light flag.

Large wavelets. Crests begin to break. Foam of

glassy appearance. Perhaps scattered white

horses.4 Moderate

breeze 14 - 19 mph Raises dust and loose

paper, small branches are moved.

Small waves, becoming larger; fairly frequent

white horses.5 Fresh breeze 20 - 25 mph Small trees in leaf

begin to sway, crested wavelets form on

inland waters.

Moderate waves, taking a more pronounced long

form, many white horses are formed. Chance of

some spray.6 Strong breeze 26 - 32 mph Large branches in

motion, whistling heard in telegraph wires,

umbrellas used with difficulty.

Large waves begin to form, the white foam

crests are more extensive everywhere. Probably

some spray.7 Moderate gale 33 - 41 mph Whole trees in motion,

inconvenience felt when walking against

the wind.

Sea heaps up and white foam from breaking

waves begins to be blown in streaks along the

direction of the wind.8 Fresh gale 42 - 50 mph Breaks twigs off trees,

generally impedes progress.

Moderately high waves of greater length, edges of

crests begin to break into spindrift. The foam is blown in well-marked

streaks along the direction of the wind.

9 Strong gale 51 - 61 mph Slight structural damage occurs

(chimney-pots and slates removed).

High waves. Dense streaks of foam along the

direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect

visibility.10 Storm 62 - 74 mph Seldom experienced

inland; trees uprooted, considerable structural

damage occurs.

Very high waves with long over- hanging

crests. The resulting foam, in great patches, is

blown in dense white streaks along the

direction of the wind. On the whole the surface of the sea takes on a white

appearance. The 'tumbling' of the sea becomes heavy and

shock-like. Visibility affected.

11 Violent storm 75 - 91 mph Very rarely experienced;

accompanied by wide-spread damage

Exceptionally high waves (small and medium-size ships might be for a time lost to view behind the

waves). The sea is completely covered with

long white patches of foam lying along the direction of the wind.

Everywhere the edges of the wave crests are

blown into froth. Visibility affected.

12 Hurricane 92 + mph   The air is filled with foam and spray. Sea

completely white with driving spray; visibility very seriously affected.

bedrock - General term for the underlying rock layer in a region.

benthic - Benthic organism live at the bottom of a body of water such as sea, river, lake etc. These organisms are sometimes referred to collectively as the "benthos".

bergschrund - The crevasse formed where a glacier meets the solid rock of a mountain slope, usually very wide and the widest crevasse on the glacier.

beset - The situation of a ship when closely surrounded by ice on all sides.

biota - All of the living organisms of an ecosystem or an area, plants, animals, bacteria, fungi etc.

black ice - Newly-formed iced over sea water. It is thin enough for the dark water to be visible through it and can be crossed only at speed by a light sledge.

blizzard - A cold storm with winds of at least 56 kilometres per hour (35 miles per hour) and temperatures below - 6.7°C (20°F). Usually also characterized by poor visibility due to snow blowing around. Little snow may actually fall during a blizzard, the high winds pick up snow from the ground and carry it around, visibility is often greatly reduced.

brash ice - Ice rubble, loose pieces of ice of various sizes from gravel sized to table sized. Originates from sea-ice that is breaking up or commonly as debris from calving ice bergs or ice bergs that break up as part of their ongoing erosion. Whenever one large piece of ice falls off another, brash is also generated and can cover quite large amounts of sea. There were times in Antarctica when we would gather brash ice that had blown into the cove where our base was to melt down and use as fresh water. The ice usually came from ice bergs that had broken up off shore, with the wind blowing it into the cove.

breakable crust - A dreadful surface over which to travel. A layer of snow that has hardened on top and sunk below. Walking across such an area means that you lift your foot and place it as for a normal step, but just a few inches higher, it takes most of your weight, but as you lift your weight onto it, at the last second the crust breaks and you're standing there with both feet a few inches below the surface crust. As much effort as walking up stairs just to stay on the level, going up hill is doubly hard.

Ccalve - The formation of an iceberg from a glacier. Once the ice flowing from a glacier reaches a body of water it begins to float and may crack at the "hinge zone", once free of the glacier a piece of ice becomes an iceberg and the glacier has calved.

cirrus clouds - Thin, wispy high altitude clouds that form at heights of 6 to 12 kilometres (3.8 to 7.6 miles).

climatology - The study of weather conditions over long periods of time.

commensal - Plants and / or animals living together and gaining benefit from the relationship. Generally a fairly loose bond and not as intimate as a symbiotic relationship.

congelation ice - A type of sea ice that forms underneath frazil ice.

continental shelf - The region in the ocean around a continent between the shoreline and the continental slope. An area of shallow water where the depth is usually less than 200 meters (650 feet). In Antarctica however, the continental shelf averages 500 meters in depth (1640 feet)! The continental shelf has formed by slow deposition of sediment eroded from the continent and has a gentle slope (around 1°).

continental slope - Narrow, steep (3° to 6° slope) transition zone between the shallow shelf and the deep ocean floor.

Coriolis effect - moving objects appear to deflect from their anticipated straight-line course. Coriolis effect is a result of the rotation Earth (and an observer's position on it). Responsible for the fact that water spirals down a plug-hole rather than going straight and the direction is different in each hemisphere. Only at the equator does water go straight down.

crevasse - A deep, usually vertical, crack or split in a glacier, occurs as a result of the brittle ice flowing over a uneven surface beneath the ice. Crevasses can easily become covered by blown snow, even very wide ones. Great care must be taken when crossing ice and snow fields to avoid them.

cryosphere - That portion of Earth's surface that is permanently frozen through the year.

cyanobacteria - Very specialized acellular organisms classified as blue-green algae. Cyanobacteria can photosynthesize, making their own food from sunlight. They are exceptionally tough organisms, able to colonize and survive in harsh environments. 

Ddesert - An area where there is little moisture due to there being little precipitation is low and evaporation is high. Precipitation usually is less than 25 centimetres a year (10 inches). Large deserts include the Sahara Desert in Northern Africa or the continent of Antarctica.

diatoms - Single celled planktonic algae with external skeleton made of silica. The skeletons, or tests, of dead diatoms sink to the sea floor and accumulate in the sediment. If sufficient quantities of skeletal material accumulate, a diatomaceous mud (10% diatoms) or diatomaceous ooze (>30% diatoms) results. The chlorophyll from the diatoms may give it greenish tinge.

diversity - The variety of different characteristics, features or organisms. The variety of species in a given region or the number of different species in a particular place. High diversity usually means a more stable and less easily disturbed ecosystem.

downwelling - In oceanography, the replacement of deep waters by surface waters moving down because of a change in temperature or more rarely salinity. Downwelling may bring waters rich in oxygen to the deeper parts of the ocean or lake.

draft - The distance below the water level (sea level) the bottom of an iceberg reaches. In some cases, icebergs are blown into shallow waters by storms and the bottom ploughs into the ocean causing the iceberg to get stuck. Draft also refers to how far below the water line the keel of a ship reaches and so determines how close into shore the ship can go.

EEast Wind Drift (Antarctic Coastal Current) - Westward flowing ocean surface current that flows anti-clockwise around Antarctica, driven by the polar easterlies.

easterlies - Winds that blow from the east (yup-really). The polar easterlies blow close to the continent and help move the ocean surface currents known as the east wind drift.

ecology - The study of the abundance of organisms in an ecosystem and the relationships between the organisms and their environment.

ecosystem - A particular environment, large or small, with characteristic physical conditions and types of organisms living there.

elevation - The height of an object or area above a particular reference point, usually the height above sea level.

evaporation - Change in state from a liquid or a solid to a gas. Evaporation takes place most quickly in an arid or dry environment when there is little or no water vapour in the air. Antarctica is arid and solid ice can "evaporate" or turn into a gas, particularly if a (relatively) warm wind blows across a snow or ice field. The change from a solid directly to a gas is properly called sublimation - like the "smoke" you get when you open the freezer door.

extraordinary Katabatic wind - Katabatic wind that is particularly long-lasting (days to even weeks) and remains fairly constant in strength during that time.

Ffast ice - Sea ice that forms in situ along the coastline and remains attached.

fauna - Animals. Antarctic fauna includes seals, penguins, whales, krill, ice-fish, nematode worms, mites, and wingless midges (plus a few other animals). Also sometimes used in the phrase "charismatic mega-fauna" large animals with charisma - penguins, seals, whales

finnesko - Boots made entirely from fur including the sole. Originally an Inuit item of clothing, no longer in use, much used in the heroic age of Arctic and Antarctic exploration. Packed with sennegrass, a dried grass for additional insulation.

firn - A transitional stage between snow and glacial ice, a type of snow that has survived a summer melting season and has become more compact than freshly falling snow.

fissure - A long, very deep, narrow opening, sometimes used instead of crevasse.

fjord (fiord) - A long, narrow, steep-walled, u-shaped coastal inlet. Fjords typically have been excavated by glaciers.

flora - Plants. Fairly limited in Antarctica, mainly mosses.

frazil ice - Ice crystals in the water column, usually near the water surface. Frazil ice crystals are not oriented in an organized manner, and have the appearance of slush or separated needles, diving through frazil ice you can see that below the main body, the crystals are quite large and separate. The first stage in the formation of sea ice.

frost smoke - Condensed water vapour that forms as a mist above any open sea water in very cold weather.

Ggale - A strong wind. On the Beaufort Scale - used to gauge the speed of the wind, a gale has winds of 39 to 46 miles per hour (62 to 74 kilometres per hour). Gales can break twigs off trees (not that you can tell in Antarctica) and make walking very difficult. Gales are common in Antarctica.

geology - The study of Earth, the history of the rocks, what processes that have occurred and are occurring on and within it (to the rocks). 

geomagnetic pole - If the Earth's molten metallic core is imagined to be a giant bar magnet, the Geomagnetic Pole is where you would expect the magnetic field lines to converge. But ocean currents, mountains and solar activity mess things up, similar to how a compass can be confused if you hold it near something metal. Because of this while the geomagnetic pole is where the needle of a compass should point straight downwards, it is the magnetic pole where this is actually the case. The Magnetic Pole can move many kilometres in a day, whereas the Geomagnetic Pole moves much more slowly.

The geomagnetic poles aren't fixed and wander about, currently the south geomagnetic pole is about 1160 kilometres (725 miles) north (think about it) of the south geographic pole (close to the Russian Vostok Station).With thanks to Glenn Grant - 60South.com

geophysics - The study of the physical properties of Earth as a planet. Geophysicists may study the interior of the Earth, the geomagnetic field of the Earth, or the Earth's gravity field. Most of the work is done using very high tech equipment and requires much translation to be understood by normal people.

geothermal - Geo - earth, thermal - heat. Heat generated within the interior of Earth. Visible indications of geothermal activity are geysers when underground water comes into contact with a heat source, such as hot rocks near a volcano. In Antarctica, Deception Island is geothermally active, there are also thought to be several regions on the continent where

glaciers are melted from below by geothermal heat making them flow more quickly at those regions.

glacial erosion - The wearing down of the Earth's surface by glaciers. Rock debris at the bottom of a glacier scrapes and erodes the surface over which the glacier flows like a giant hugely heavy piece of sand paper.

glaciation - The formation, activity, and retreat of glaciers through time. The glaciation of a region refers to the growth of ice over that region. Large parts of the Northern Hemisphere experienced glaciation in the past - ice ages.

glacier - A river of ice. Usually a mixture of ice, air, water, and rock debris formed at least partially on land. They are large enough for the ice to flow with gravity.  Glaciers can be small valley glaciers, ice streams, ice caps, and ice sheets. The term glacier also includes ice shelves if they are fed by glaciers. Freshwater.

glaciology - The study of the physical and chemical properties of snow and ice, not necessarily just of glaciers. Glaciologists might study the movement of ice sheets, and how ice flows. Also the study of how snow slowly changes to glacier ice.

glaze - A smooth, clear coat of ice. grease ice - A thin layer of ice crystals beginning to show organization on the water surface with a greasy appearance and like a slush puppy in consistency. 

grounding line - The point a glacier that is flowing into a sea or lake loses contact with seafloor and begins to float as an ice shelf.

Hhanging valley - A u-shaped valley that joins the wall of a larger valley. The smaller valley floor "hangs" above the larger valley floor. Hanging valleys are made by valley glaciers carving out a path, when the glacier was active the smaller valley glacier would have flowed into the larger valley glacier.

heat reservoir - Places where heat is absorbed and then distributed slowly to the surroundings. Oceans and other large bodies of water act as heat reservoirs. They absorb heat and slowly pass it to the atmosphere. This is one reason why coastal areas and islands never get as cold as areas inland in winter. The heat doesn't have to be very great, the sea can still seem very cold, as long as it is above the surrounding air temperature, heat will be transferred.

highs (high pressure zones) - Places where the atmospheric pressure is above the surrounding region. Clear weather often accompanies high pressure systems.

hoarfrost - A light, feathery ice coating built up from water particles in the air crystallizing out into tiny ice sculptures (you have to look carefully).

ice age (glacial period) - Periods in the Earth's history when the climate was colder and glaciers expanded to cover large areas of the Earth's surface. Ice ages have come and gone many times and will probably continue to do so.

ice blink - A brightness on the horizon, showing in the clouds above it caused by reflection of sunlight from sea ice even in overcast conditions, such a sight is often called an "ice sky". Conversely, a darkness on the horizon when surrounded by ice denotes the presence of open water and is called a "water sky".

ice cap - A large dome-shaped mass of ice that is thick enough to cover all the landscape beneath it so appearing as a smooth coating of ice. Ice caps are smaller than ice sheets, usually under 50,000 square kilometres (19,000 square miles). Ice caps can deform and flow with gravity and spread outward in all directions. Freshwater.

ice cliff - Walls of ice where glaciers meet the sea. Ice cliffs occur because icebergs calve from the front of them giving a continually breaking edge the full height of the glacier. Freshwater.

ice crystals - Tiny particles of ice that grow on all surfaces when the air is supersaturated with water (cold air doesn't hold much moisture so ice crystals are readily formed in Antarctica). Ice crystals account for the majority of the accumulation of glacial ice on the Polar Plateau. They may also be referred to as ice needles, even though they are not needle shaped. Freshwater.

ice floe - A large, flat, sheet of sea ice that has broken off contact with the coast where it was formed and is floating in open water. Sea-water.

ice foot - A "shelf" of ice that forms around many Antarctic shores in the winter time. Sometimes formed by sea spray, often formed where sea-ice joins the land, as the tide rises and falls, a layer of ice is deposited which builds up. Once the sea ice blows out in the spring a distinct ledge several feet high is left behind that can be difficult to cross for men and also for animals. Sea-water

ice sheet - A large mass of ice that is thick enough to cover the landscape beneath it so appearing as a smooth coating of ice. Ice sheets can deform and move with gravity, they are larger than ice caps. Ice sheets cover much of Greenland and Antarctica. Freshwater.

ice shelf - A large flat-topped sheet of ice that is attached to land along one side and floats in the sea or a lake. Formed where a glacier or ice shelf has reached the water and kept flowing, it is fed from the landward side and eroded from the seaward side by the calving of icebergs and melting. Freshwater.

ice stream - A rapidly moving current of ice in an ice sheet or ice cap. Ice streams flow more quickly than the surrounding ice and remove ice from the ice sheet. Antarctic ice streams may flow about one kilometre per year (0.6 miles per year). Freshwater.

ice tongue - A long, narrow, projection of ice out from the coastline, similar in origin to an ice shelf, but usually formed where a valley glacier flows rapidly to the sea or a lake. Freshwater.

iceberg - A large piece of floating ice that has calved, or broken off, a glacier or ice shelf. Icebergs occur in lakes and the ocean and can be vast, the size of islands or small countries. Freshwater.

ionosphere - The electrically-charged layer of the atmosphere that extends from 80 to 400 kilometres (50 to 250 miles) above the Earth's surface. The ionosphere absorbs much of the short wave-length radiation from the sun. As the radiation passes through the ionosphere, it interacts with nitrogen molecules and oxygen atoms. These molecules and atoms absorb the

radiation, but in the process they lose an electron (a negatively charged particle) and become a positively charged ion. The ionosphere is where auroras originate.

Kkatabatic winds - Wind that results from dense, cold air flowing down a slope by gravity. Over Antarctica, air cools over the high plateau region and flows towards the coast, by the time it gets to the coast it can have reached extreme speeds and blow continuously for weeks.

Lland-based ice sheet - a large body of ice with a base mostly above sea level. The East Antarctic Ice Sheet is a land-based ice sheet. Freshwater.

lapse rate - The change in temperature associated with a change in elevation. When climbing a mountain, the temperature falls approximately 1°C for every 100m in altitude gained.

latitude - Imaginary lines that allow for the measurement of position north or south of the equator. Latitude is measured in degrees (one degree - 60 nautical miles, or 111 kilometres). The equator is at a latitude of 0° and the poles lie at latitudes of 90° north (North Pole) or 90° south (South Pole). Lines of latitude differ in length according to how far north and south they are.

lead - Long, narrow opening or fracture in sea ice. Leads can be useful to shipping because they do not have to waste fuel and time by breaking ice, they can be disastrous if travelling over sea-ice as the path is no longer there. Leads are also useful to seals and whales that can use them to breathe and for birds that can feed on marine prey through the lead.

lichen - Symbiotic association of alga and fungus. The fungus provides protection and moisture, the photosynthetic algae provide food for the fungus. Lichens are the toughest form of plant life and can live in some of the coldest and most exposed places in Antarctica as long as they have a rock to cling to. They can actively grow and photosynthesize at well below freezing point - albeit very slowly.

limnology - The study of freshwater such as lakes, ponds, and marshes. The analysis of the physical and chemical characteristics of the freshwater as well as the plants and animals that live within them. Antarctic lakes are more affected by climatic and other changes than is the ocean and so they are seen as giving an early warning of any impending changes.

longitude - Imaginary lines that wrap around the Earth intersecting at the north and south geographic poles. Lines of longitude are numbered from 0° (the Greenwich Meridian, passing through Greenwich in London, England) to 180°. Longitudes are called east if they fall east of the Greenwich Meridian, and west if they fall west of the Greenwich Meridian. Lines of longitude are all of the same length.

Mmagnetic storm - Times when the sun radiates large amounts of ions and electromagnetic energy out towards the solar system, tied to sunspot activity. This influx of high energy disturbs the Earth's magnetic field causing interruptions to telecommunications broadcasts and particularly pretty auroras.

marine biology - The study of plants and animals living in the seas and oceans.

maritime - Bordering or next to the ocean or sea. Maritime climates are oceanic climates, and are milder than the inland climates because of the moderating influence of the sea which acts as a huge heat sink absorbing heat in the summer and giving it out in the winter.

meteorology - The study of the Earth's atmosphere and the movements of air and moisture within the atmosphere. Includes the study of the atmosphere for weather forecasting.

meteorite - Fragments of rock that reach the Earth from beyond the atmosphere. Most are believed to come from asteroids, some are believed to be pieces from other planets. Antarctica is a particularly good place to find meteorites as they show up against the snow and ice and are accumulated in some places by the flow patterns of ice streams and glaciers. migrate - Moving from one area to another. Some animals migrate in certain seasons to find better conditions, such as weather, food, or for breeding. Many whales migrate to the Southern Ocean in the summer to feed on the large the quantities of krill for example.

moss - Small, leafy-stemmed plants that grow in carpet-like mats and tufts on moist ground. Particularly abundant in maritime regions of Antarctica where conditions are too harsh for other types of plant. In Antarctica mosses often accumulate in large "moss banks".

Nnekton - Free-swimming aquatic animals that move under their own power and can move independently of ocean currents. Whales and squid and many fish are types of nekton.

niche - The life style of an organism, its "job" also - the place in which it lives, what it eats, how it gets nutrients, and the interplay it may have with the environment and other organisms.

nip / nipped - a dreaded description of a ship from the early days of polar exploration when she was trapped by ice on both sides that was pushing in hard. In contrast to the gentle sounding nature of the event, the reality was often that the ship suffered considerable damage or was broken and sunk.

nunatak - An isolated peak of bedrock that sticks above the surface of an ice sheet. They are the peaks of hills and mountains standing above the ice sheet which flows around them. They offer important information about ice covered regions as they provide a sample of the rocks that lie under the ice.

Ooceanography - The study of the ocean. The physical properties of the ocean - currents and waves (physical oceanography), the chemistry of the ocean (chemical oceanography), the geology of the seafloor (marine geology), and the organisms that live in the oceans (marine biology and marine ecology).

ordinary katabatic wind - Short-lived katabatic winds with constant direction but a highly variable speed. Originate in cold dense air flowing coastward from the high Antarctic plateau over the pole.

ozone layer - A layer in the Earth's upper atmosphere, the stratosphere that contains almost 90% of the Earth's ozone. This forms a protective blanket against the harmful ultra-violet rays coming form the sun.

Ppack ice - Often used interchangeably with sea ice. Pack ice is frozen sea that formed somewhere else and has floated to its present position carried by wind, tides and currents. It is broken up and of variable size and thickness, some pieces can be the size of a coffee table and about 1 foot (30cm) thick, other pieces are larger than a tennis court and can be 30ft (9m) or more thick. Usually pack ice is in its second season.  Sea-water

    Open pack - when the pieces of ice don't touch    Closed pack - when the pieces of ice touch

pancake ice -  Pancake ice grows from thickened grease ice and resembles pancakes or lily pads. The edges of each piece is upturned because the plates bump into each other as they gently move around in the sea. Usually between about a foot (30cm) and 6 feet (2m) across. Pancakes tend to be smaller the closer to the shore line they are. Sea-water

physical oceanography - The study of the physical aspects of the seas and oceans such as the temperature, salinity, density variation, and the optic and acoustic properties of the ocean. Also includes the study of nature of currents, waves, and tides.

phytoplankton - Plant plankton. Microscopic free-swimming or suspended marine or freshwater plants within the plankton. Plankton is defined as being those organisms that inhabit the upper regions of a body of water, but cannot move about against the influence of water movements such as currents, they move generally with the water although may be able to move small distances. Phytoplankton includes diatoms and other photosynthetic algae, a crucial part of almost all aquatic food webs.

plate tectonics - A theory that ties together many observations made about the activity and movement of Earth's crust (earthquakes, volcanoes) and creation of ocean basins. Plate tectonics divides the surface of the globe into a number of rigid plates that move around the earth's surface over the period of millions of years. 

polar - To do with the regions of the north and or south poles of the planet. The poles are cold, icy regions, a polar climate is a cold climate, with average temperatures less than 10°C (50°F).

polar easterlies - Winds that blow from the east as they flow off the high Antarctic polar plateau. Polar easterlies help generate ocean surface currents (east wind drift) in the Southern Ocean.

Polar Front (Antarctic Convergence) - A surface boundary where which the colder, north flowing Antarctic Surface Waters sink beneath warmer circulating waters. This marks a change in the oceans surface temperature and also chemical composition. North of the convergence, the area is known as the sub-Antarctic.

Polar Plateau - The relatively flat, high altitude central region of the East Antarctic Ice Sheet. The plateau has an average height of 2000 meters (about one mile) above sea level and a smooth surface with a small slope towards the coast in all directions.

polynyas - A polynya is an area of open water in pack ice or sea ice, they may be kept open by constant winds or the upwelling of water and so tend to recur in the same locations year after year. They are particularly important for wildlife as they allow mammals such as whales and seals to have a breathing hole and birds access to the sea in order to fish.

precipitation - Rain, snow, hail, sleet etc. moisture falling from clouds to the surface of the Earth, usually as rain, snow, and ice. The amount of precipitation is always measured as water or rain equivalent so allowing for the fact that snow can have various structures and densities

productivity - A term used to describe the rate of production in an ecosystem. Extra nutrients usually increase productivity.

Rreflectivity - The amount of light or energy that bounces off a surface relative to the amount of light or energy that reached the surface. A mirror is an example of an object with high reflectivity. The ocean has low reflectivity. Reflectivity may also be called albedo.

rookery - A colony of rooks, the term is also used for a colony of penguins.

rotten ice - Old ice, partially melted and often honeycombed

S

Sastrugi - wind blown snowpicture courtesy NOAA

salinity - The amount of dissolved salts contained in sea water. The average salinity of sea water is 35 parts per thousand, but can vary with location.

sallying a ship - from the early days of polar exploration, causing the ship to roll by crew and passengers running from side to side to prevent adhesion of the ice around her.

sastrugi - Irregular ridges of snow on a small scale (rarely more than 1 foot, 30cm) that lie parallel to the direction of the wind. Sastrugi can make travel very awkward or difficult, they can be quite soft or as hard as ice.

sea ice - A general term for any ice that forms from frozen seawater. Sea ice covers large parts of polar waters in the winter and melts back each summer.

sleet - Frozen or partially frozen rain that form when rain passes through a layer of air that is below the freezing temperature, falls to earth as a slush. Freshwater.

South geographic pole - 90°S. The south geographic pole is the southern location where the axis of rotation of Earth intersects Earth's surface.

South geomagnetic pole - The point on Earth's surface in the Southern Hemisphere where the axis of the Earth's magnetic pole intersects. The south geomagnetic pole is approximately 1160 kilometres (725 miles) north of the south geographic pole (think about it). The south geomagnetic pole is tilted about 12 degrees to the axis of rotation of the Earth (geographic pole).

South magnetic pole - the point on Earth's surface that a south-seeking compass needle seeks. At the South magnetic pole a compass needle will point vertically downwards. This point is currently off the coast of Wilkes Land and wanders around.

stratosphere - The layer of the atmosphere that is above the troposphere, it extends from approximately 10 to 50 kilometres (6 to 31 miles) above Earth's surface. The upper region contains the ozone layer.

subglacial - Underneath the glacier.

supercooled - A condition when water is still liquid even though it is at a temperature at which it normally would freeze. Often under these conditions a small physical movement a small knock or tap will cause the water to freeze almost immediately.

Ttabular iceberg- A flat-topped iceberg, like a table. Freshwater.

terrestrial - Dry land. Terrestrial flora and fauna live on land not in water.

tide crack - Any crack in sea ice that is caused by the rise and fall of the tide. As the tide rises so the area of the sea increases and a crack forms, as the tide falls, so the area decreases and the crack closes. Often form around offshore rocks, between the shore and sea-ice, around grounded ice bergs or even stretching for miles between islands.

tongue - A mass of ice projecting from a glacier into the sea. It is still fixed to and forms a part of the larger glacier. freshwater

trade winds - One of three major circulation cells in both the northern and southern hemispheres. The trade winds from approximately 0° to 30° north or south latitude. Within the regions of the trade winds, prevailing winds blow toward the west. They were given their name as in the days of sailing ships, they aided the progress of the ships and hence the trade of goods carried by those ships.

U

ultraviolet radiation (UV) - A part of the electromagnetic spectrum that has shorter wavelengths than visible light. Ultraviolet radiation has more energy than visible light and can damage tissue (like human skin). Much of the ultraviolet radiation from the sun is absorbed within the ozone layer before it reaches the Earth's surface.

upper atmosphere physics - The study of processes that take place in the upper atmosphere. Includes study of the interactions between the various atmospheric gases and cosmic radiation, such as the ozone layer.

upwelling - An oceanographic term, the rising of deeper waters to replace surface waters. Upwelling often brings waters rich in nutrients to the surface, resulting in a region where ocean productivity is high.

WWest Wind Drift (Antarctic Circumpolar Current) - A Southern Ocean surface current flowing east and driven by westerly winds. The West Wind Drift carries a large volume of water and it is a strong current because no continents are in the way of the flow path.

white-out - A weather condition in which the horizon cannot be identified and there are no shadows. The clouds in the sky and the white snow on the ground blend - described as like walking along inside a ping-pong ball. White out conditions are potentially dangerous because it is difficult to find a point of reference and it is very easy to walk over a cliff or fall down a crevasse in such conditions.

wind chill - A way of describing the temperature that takes into consideration the effect of the wind speed in the temperature reported. Wind makes any temperature feel colder and wind chill factor is a way of expressing how cold the wind might make the temperature feel. First described after experiments by the American scientist Paul Siple on baked bean cans containing water and a thermometer left in the wind.

Zzooplankton - Animal plankton. Microscopic free-swimming or suspended marine or freshwater animals within the plankton. Plankton is defined as being those organisms that inhabit the upper regions of a body of water, but cannot move about against the influence of water movements such as currents, they move generally with the water column although may be able to move small distances. Many marine animals spend part of their lives as zooplankton, often as a juvenile life stage. One of the most important components of the Antarctic zooplankton is krill.

Source :www.coolantarctica.com