ice between March and September.]] Sea ice is largely formed from seawater that freezes. Because the oceans consist of saltwater, this occurs below the freezing point of pure water, at about -1.8 °C (28.8 °F).

Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Icebergs are compacted snow and hence are fresh water from the beginning; sea ice loses its salt during its process of formation from sea water and thus eventually is fresh as well.

Types of sea ice

in winter. The Gulf of Bothnia and White Sea are covered with sea ice.]] Land-fast ice, or simply fast ice, is sea ice that has frozen along coasts ("fastened" to them) or to the sea floor over shallow parts of the continental shelf, and extends out from land into sea. Unlike drift ice, it does not move with currents and wind.

Drift ice consists of ice that floats on the surface of the water, as distinguished from the fast ice, attached to coasts. When packed together in large masses, drift ice is called 'pack ice''. Pack ice may be either freely floating or blocked by fast ice while drifting past.

Pancake ice is sea ice broken into small round chunks looking like pancakes.

The most important areas of pack ice are the polar ice packs formed from seawater in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs significantly change their size during seasonal changes of the year. Because of vast amounts of water added to or removed from the oceans and atmosphere, the behavior of polar ice packs have a significant impact of the global changes in climate, see "Polar ice packs" for details.

An ice floe is a floating chunk of ice that is less than 10 kilometers (six miles) in its greatest dimension. Wider chunks of ice are called ice fields.

Formation of sea ice

. Plates are typically 1 - 3 meters across.]] Only the top layer of water needs to cool to the freezing point. Convection of the surface layer involves the top 100 – 150 m, down to the pycnocline of increased density.

In calm water, the first sea ice to form on the surface is a skim of separate crystals which initially are in the form of tiny discs, floating flat on the surface and of diameter less than 2–3 mm. Each disc has its c-axis vertical and grows outwards laterally. At a certain point such a disc shape becomes unstable, and the growing isolated crystals take on a hexagonal, stellar form, with long fragile arms stretching out over the surface. These crystals also have their c-axis vertical. The dendritic arms are very fragile, and soon break off, leaving a mixture of discs and arm fragments. With any kind of turbulence in the water, these fragments break up further into random-shaped small crystals which form a suspension of increasing density in the surface water, an ice type called frazil or grease ice. In quiet conditions the frazil crystals soon freeze together to form a continuous thin sheet of young ice; in its early stages, when it is still transparent, it is called nilas. When only a few centimeters thick this is transparent (dark nilas) but as the ice grows thicker the nilas takes on a grey and finally a white appearance. Once nilas has formed, a quite different growth process occurs, in which water molecules freeze on to the bottom of the existing ice sheet, a process called congelation growth. This growth process yields first-year ice, which in a single season may reach a thickness of 1.5–2 m.

In rough water, fresh sea ice is formed by the cooling of the ocean as heat is lost into the atmosphere. The uppermost layer of the ocean is supercooled to slightly below the freezing point, at which time tiny ice platelets, known as frazil ice, form. As more frazil ice forms, the ice forms a mushy surface layer, known as grease ice. Frazil ice formation may also be started by snowfall, rather than supercooling.

Slush is a floating mass formed initially from snow and water. Shuga is formed in agitated conditions by accumulation of slush or grease ice into spongy pieces several inches in size.

Waves and wind then act to compress these ice particles into larger plates, of several meters in diameter, called pancake ice. These float on the ocean surface, and collide with one another, forming upturned edges. In time, the pancake ice plates may themselves be rafted over one another or frozen together into a more solid ice cover, known as consolidated ice pancake ice. Such ice has a very rough appearance on top and bottom.

Sea ice is largely fresh, since a lot of the ocean salt is expelled during ice formation. The resulting ice is riddled with minute brine-filled channels and consequently is still salty (about 1% salt, compared with about 3.5% salt in the ocean). The expelled brine has an important bearing on the ocean circulation.

If sufficient snow falls on sea ice to depress the freeboard below sea level, sea water will flow in and a layer of ice will form of mixed snow/sea water. This is particularly common around Antarctica.

Russian scientist Vladimir Vize (1886–1954) devoted his life to study the Arctic ice pack and developed the Scientific Prediction of Ice Conditions Theory, for which he was widely acclaimed in academic circles. He applied this theory in the field in the Kara Sea, which led to the discovery of Vize Island.

Yearly freeze and melt cycle

Sea ice freezes and melts due to a combination of factors, including the age of the ice, air temperatures, and solar insolation. During the winter the area of the Arctic Ocean covered by sea ice increases, usually reaching a maximum extent during the month of March. The area covered in sea ice then decreases, reaching its minimum extent in September most years. First-year ice melts more easily than older ice for two reasons: 1) First-year ice is thinner than older ice, since the process of congelation growth has had less time to operate; and 2) first-year ice is less permeable than older ice, so summer meltwater tends to form deeper ponds on the first-year ice surface than on older ice, and deeper ponds mean lower albedo and thus greater solar energy capture.

Monitoring and observations

Satellite data has allowed the tracking of sea ice extents since 1978. During the warmest years, like the winter of 2005-2006, sea ice is observed to reach a winter maximum extent that is smaller than in the years before or after. The summer minimum Arctic ice extent for 2010 was the third lowest over the period of satellite observations of the polar ice. The minimum record summer Arctic sea ice extent was in 2007.

Ecology

]] .]]

Sea ice is part of the Earth's biosphere. When sea water freezes, the ice is riddled with brine-filled channels which sustain sympagic organisms such as bacteria, algae, copepods and annelids, which in turn provide food for animals such as krill and specialised fish like the Bald notothen, fed upon in turn by larger animals such as Emperor penguins and Minke whales.

The decline of seasonal sea ice is putting the survival of Arctic species such as ringed seals and polar bears at risk.

See also

Arctic sea ice ecology and history

Arctic shrinkage

Drift ice station

Drift station

Ice class

Ice pier

Ice shelf

Measurement of sea ice

Polynya

Sea ice concentration

Sea ice growth processes

Vladimir Wiese

Zhubov scale

References

Konstantin Y. Vinnikov, Donald J. Cavalieri, and Claire L. Parkinson, V33, L05704, A model assessment of satellite observed trends in polar sea ice extents.

External links

NOAA Arctic theme page

Ice in the Sea Chapter from Nathaniel Bowditch's American Practical Navigator

Cryosphere Today: Current Arctic sea ice conditions

Data source for sea ice picture

Marine Modeling and Analysis Branch ">Marine Modeling and Analysis Branch

Everything you ever wanted to know about sea ice but were afraid to ask

NSIDC Sea Ice Index

Global Sea Ice Extent and Concentration: What sensors on satellites are telling us about sea ice

BBC News, 28 September 2005, "Arctic ice 'disappearing quickly'"

German remote-sensing sea ice group including high-resolution ice maps.

Video that depicts the formation of sea ice in the Baltic sea

Category:Earth phenomena Category:Aquatic ecology Category:Glaciology

Coordinates	28°36′36″N77°13′48″N
Group	Polish people (Polacy)
Population	ca. 60 million (est.)
Popplace	38,860,000
Region1
Pop1	8,977,235
Ref1
Region2
Pop2	1,500,000 - 2,000,000
Ref2
Region3
Pop3	1,500,000
Ref3
Region4
Pop4	1,250,000
Ref4
Region5
Pop5	984,565
Ref5
Region6
Pop6	900,000
Ref6
Region7
Pop7	500,000 - 560,000
Ref7
Region8
Pop8	500,000
Ref8
Region9
Pop9	294,549
Ref9
Region10
Pop10	205,500
Ref10
Region11
Pop11	200,000
Ref11
Region15
Pop15	78,340
Ref15
Region12
Pop12	144,130
Ref12
Region13
Pop13	120,000
Ref13
Region14
Pop14	100,000
Ref14
Region16
Pop16	78,305
Ref16
Ref
Region17
Pop17	73,000
Ref17
Region18
Pop18	51,968
Ref18
Region19
Pop19	51,397
Ref19
Region20
Pop20	50,000
Ref20
Region23
Pop23	34,057
Ref23
Region21
Pop21	45,000
Ref21
Region22
Pop22	39,500
Ref22
Region24
Pop24	30,000
Ref24
Region25
Pop25	30,000
Ref25
Region26
Pop26	21,000
Ref26
Region27
Pop27	10,540
Ref27
Region28
Pop28	5,300
Ref28
Region29
Pop29	4,174
Ref29
Region30
Pop30	3,671
Ref30
Region31
Pop31	3,000
Ref31
Region33
Pop33	2,200
Ref33
Region34
Pop34	1,000
Ref34
Region34
Pop35	300
Ref35
Languages	Polish
Rels	Predominantly Roman Catholicism, also Eastern Orthodoxy, Protestantism and Judaism.
Related-c	Czechs, Slovaks, Sorbs

The Polish people, or the Poles ( , singular Polak) are a nation indigenous to Poland. They are bonded by the Polish language, which belongs to the Lechitic subgroup of West Slavic languages of Central Europe. A wide-ranging Polish diaspora exists throughout Europe (Germany, France, the UK, Belarus, Lithuania and Ukraine), the Americas (the US, Brazil and Argentina) and Australia. Polish citizens live predominantly in Poland. The city of Chicago has the world's largest populations of Polish people, after Warsaw.

There is no commonly accepted definition of the Polish people. According to the preamble of the Constitution of the Republic of Poland, the Polish nation consists of all citizens of Poland. The Polans of Giecz, Gniezno, and Poznań were one of the most influential tribes of Greater Poland and managed to unite many other Lechitic tribes in the area under the rule of what became the Piast dynasty, thus giving birth to a new state. The Polish word for a Polish person is Polak (masculine) and Polka (feminine). The feminine form typically refers in English to the style of music (i.e. Polka).

The inhabitants of Poland live in a number of traditional and historically-geographical regions. There are seven such major areas of Poland - Mazovia, Pomerania, Greater Poland, Lesser Poland, Warmia, Mazury and Silesia.

Proto-European lineage

Polish people show the characteristic R1a genes of a common Paleolithic male ancestorship at a frequency of 55.9-56.4%. This lineage includes haplotype Eu19 distinguished by M17 lineage. Its frequency increases eastward from south-western France and reaches a maximum in Poland, Hungary, and west Ukraine.

As a result of genocide on Polish lands, evacuation, repatriation, and expulsion during and after World War II, and territorial changes which were assigned by the Big Three allies to Poland after World War II. as well as the ensuing mass migrations and border shifts, "the population of Poland became one of the most ethnically homogeneous in the world," according to Encyclopædia Britannica. "In addition, minority ethnic identity was not cultivated publicly until after the collapse of communism in 1989." The CIA World Factbook defines the ethnic composition of Poland as being 96.7% Polish with 0.4% Germans, 0.1% Belarusians, 0.1%, Ukrainians, and 2.7% other and unspecified (2002 census). The present day homogeneity contrasts with the World War II period, informs the U.S. Department of State: "when there were significant ethnic minorities - 4.5 million Ukrainians, 3 million Jews, 1 million Belarusians, and 800,000 Germans." The majority of the Jews were murdered during the Holocaust. Most Germans left ahead of the Nazi-Soviet front, while most Ukrainians and Belarusians remained in territories incorporated into the USSR. "Small Ukrainian, Belarusian, Slovakian, and Lithuanian minorities reside along the Polish borders, and a German minority is concentrated near the southwest city of Opole. "

In the first half of the 16th century, the historian Marcin Kromer in his work "de Situ Polonia; et gente Polona" donated to the Henry III, wrote: "colors for faces of Polish people (peasants) were white, yellowish or whitish hair, handsome figure, with average height" They were not racially homogeneous, but composed of mixtures of the types, according to Czekanowski, with a few trivial exceptions. Before 1939 the inhabitants of Poland were divided between four distinct types — the Nordic, Alpine, Mediterranean and Armenoid neighbors or brothers. Some of these types centred around Western Poland, Masovia, Pomerania, Volhynia and Greater Poland. The Mediterranean and Alpine types were mainly represented in Silesia and Lesser Poland.

The research conducted in 1955 had shown that 55% of Poles have light hair (16-12 scale of Fischer–Saller), and about 72% have light eyes (A-P scale of Fischer–Saller). By the end of the 20th century, heights averaged at 178 cm (5'10") for 20-year-old males, and 166 cm (5'5") for 20-year-old females.

Statistics

The majority of the Polish nation is descended from the ancient Leches of the Sagas, the same people as the Lygians of Tacitus, and the Lecicavians of the middle ages. At the early period, however, the Western of Visigoths, were settled on the banks of the Vistula, and formed, perhaps, in many places, the dominant race. It seems to be evident that the Poles were not descended from the Sarmatians.

Polish people are the sixth largest national group in Europe. Estimates vary depending on source, though available data suggest a total number of around 60 million people worldwide (with roughly 21 million living outside of Poland, many of whom are not of Polish ethnicity, but Polish nationals).

The term "Polonia" is usually used in Poland to refer to people of Polish origin who live outside Polish borders, officially estimated at around 10 to 20 million. There is a notable Polish diaspora in the United States, Canada, and Brazil. France has a historic relationship with Poland and has a relatively large Polish-descendant population. Poles have lived in France since the 18th century. In the early 20th century, over a million Polish people settled in France, mostly during world wars, among them Polish émigrés fleeing either Nazi occupation or later Soviet rule.

In the United States a significant number of Polish immigrants settled in Chicago, Ohio, Detroit, New York City, Orlando, Pittsburgh, Buffalo, and New England. The highest concentration of Poles in the United States is in New Britain, Connecticut. The majority of Polish Canadians have arrived in Canada since World War II. The number of Polish immigrants increased between 1945 and 1970, and again after the fall of Communism in 1989. In Brazil the majority of Polish immigrants settled in Paraná State. The city of Curitiba has the second largest Polish diaspora in the world (after Chicago) and Polish music, dishes and culture are quite common in the region.

In recent years, since joining the European Union, many Polish people have emigrated to countries such as Ireland, where an estimated 200,000 Polish people have entered the labour market. It is estimated that over half a million Polish people have come to work in the United Kingdom from Poland. Since 2011, Poles have been able to work freely throughout the EU and not just in the UK, Ireland, Denmark and Sweden where they have had limited rights since Poland's EU accession in 2004. The Polish community in Norway has increased substantially and has grown to a total number of 120,000, making Poles the largest immigrant group in Norway.

Before World War II many Polish Jews became followers of Zionism and subsequently emigrated to the British Mandate of Palestine. Following the Holocaust, the vast majority of surviving Polish Jews moved to Israel. Poland is the largest single place of origin of Israeli Jews. :(for ethnic Poles living abroad see Polonia, for those living and working in the United Kingdom see Polish British)

Culture

The culture of Poland is closely connected with its intricate 1000 year history Located in Central Europe, its unique character developed as a result of its geography at the confluence of fellow Central European cultures (German, Western Ukrainian, Czech and Austrian) the Western European cultures (French and Dutch), Southern European cultures (Italian and Turkish), Northern European cultures (Lithuanian, Swedish and Danish) and Eastern European cultures (East Ukrainian and Russian) along cultural influence of the Jewish culture. Confluences were conveyed by immigrants (Jewish, German and Dutch), political alliances (with Lithuania, France and Sweden), conquests of the Polish state (Ukraine and Latvia) or conquerors of the Polish lands (Tsardom of Russia, Kingdom of Prussia and the Habsburg Monarchy, later on Austrian Empire and Austria-Hungary).

With origins in the culture of the Lechites, over time Polish culture has been profoundly influenced by its interweaving ties with the Germanic, Latinate and other ethnic groups and minorities living in Poland like the Jews. The people of Poland have traditionally been seen as hospitable to artists from abroad (especially Italy) and open to cultural and artistic trends popular in other European countries. Owing to this central location, the Poles came very early into contact with both civilizations - eastern and western, and as a result developed economically, culturally, and politically. A German general Helmut Carl von Moltke, in his Poland. A historical sketch (1885), stated that Poland prior to her partitions was "the most civilized country in Europe". In the 19th and 20th centuries the Polish focus on cultural advancement often took precedence over political and economic activity, experiencing severe crisis, especially during the II World War and in the coming years. These factors have contributed to the versatile nature of Polish art, with all its complex nuances.

Religion

Most Poles living in Poland, by far, adhere to the Christian faith, majority belonging to the Roman Catholic Church. The rest of the population consists mainly of Eastern Orthodox, Jehovah's Witnesses, various Protestant and Judaism.

Exonyms

Among the exonyms not native to the Polish people or language are: лях (lyakh) used in East Slavic languages. Today, the word Lachy is used by Eastern Slavs as synonyms for "Poles" and "Poland". The foreign exonyms include also: Lithuanian Lenkai, Hungarian Lengyelek and Turkish Leh (now considered obsolete and replaced by Polonya). The former became the basis for Poland exonyms in a number of other Middle Eastern languages, including: Armenian Լեհաստան, Lehastan; Persian, Tajik لهستان, Lahestan.

Polish tribes

The following is a list of Polish tribes—tribes which constituted the lands of Poland in the Early Middle Ages, at the beginning of the Polish state. Some of them have remained separate ethnicities while others have been assimilated into the culture of Poland. {| cellspacing="10" |- | valign="Top" |

Masovians (Masovia, in Polish "mazowszanie")

*Mazurs (Mazurians) (Masuria, in Polish "mazurzy")

*Kurpie (in Polish "kurpiowie" or "kurpie")

Polans (Polanes, Polanians, in Polish "polanie") (Warta river basin)

*Bambrzy

Silesians (in Polish "ślązacy") (Silesia)

Warmiaks (Warmia, in Polish "warmiacy")

Pomeranians (Farther Pomerania and Pomerelia, in Polish "pomorzanie")

*Kashubians (Cassubians, in Polish "kaszubi")

*Slovincians (in Polish "Słowińcy")

*Kociewiacy

*Borowiacy

Bieżuńczanie

| style="width:5%;"| | valign="Top" |

Bobrzanie

Dziadoszanie

Golęszyce

Goplans (Kuyavia and Pomerania, in Polish "goplanie", or "goplani")

Lędzianie (Lesser Poland, in Polish "lędzianie")

*Lachy Sądeckie

Opolanie (upper Odra, Silesia)

Kujawianie

Pyrzyczanie

Ślężanie (Lower Silesia)

Trzebowianie

Vistulans (Lesser Poland, in Polish "wiślanie")

Gorals (in Polish "górale", i.e. highlanders)

|} : See also: Bavarian Geographer, a list of tribes in Central Europe, composed in the 870s.

See also

Polonization

Polonia

Karta Polaka

Polish nationality law

Demographics of Poland

List of Polish Jews

List of Polish people

Name of Poland (etymology of the demonym)

Pole, Hungarian, two good friends

Poles in Germany

Poles in Lithuania

Poles in Romania

Poles in the former Soviet Union

Polish Americans

Polish Argentine

Polish Australians

Polish Brazilians

Polish British

Polish Canadians

Polish minority in the Czech Republic

Sons of Poland

Antipolonism

Polish Jokes

References

External links

; Other:

Polish Americans

Category:Lechites Category:Ethnic groups in Poland Category:Ethnic groups in Europe Category:Ethnic groups in Russia *