Geography of South America - AbsoluteAstronomy.com

The geography of South America contains many diverse regions and climates. Geographically, South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

is generally considered a continent

Continent

A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...

forming the southern portion of the American

Americas

The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

landmass

Landmass

A landmass is a contiguous area of land surrounded by ocean. Although it may be most often written as one word to distinguish it from the usage "land mass"—the measure of land area—it is also used as two words.Landmasses include:*supercontinents...

, south and east of the Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

-Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

border by most authorities, or south and east of the Panama Canal

Panama Canal

The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...

by some. South and North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

are sometimes considered a single continent or supercontinent

Supercontinent

In geology, a supercontinent is a landmass comprising more than one continental core, or craton. The assembly of cratons and accreted terranes that form Eurasia qualifies as a supercontinent today.-History:...

, while constituent regions

Subregion

A subregion is a conceptual unit which derives from a larger region or continent and is usually based on location. Cardinal directions, such as south or southern, are commonly used to define a subregion.- United Nations subregions :...

are infrequently considered subcontinent

Subcontinent

A subcontinent is a large, relatively self-contained landmass forming a subdivision of a continent. By dictionary entries, the term subcontinent signifies "having a certain geographical or political independence" from the rest of the continent, or "a vast and more or less self-contained subdivision...

s. Geopolitically and geographically, all of Panama – including the segment east of the Panama Canal in the isthmus – is generally considered a part of North America alone and among the countries of Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

.

South America became attached to North America only recently (geologically speaking) with the formation of the Isthmus of Panama some 3 million years ago, which resulted in the Great American Interchange

Great American Interchange

The Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...

. The Andes

Andes

The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

, likewise a comparatively young and seismically restless mountain range, run down the western edge of the continent; the land to the east of the Andes is largely tropical rain forest, the vast Amazon River

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

basin. The continent also contains drier regions such as eastern Patagonia

Patagonia

Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...

and the extremely arid Atacama desert.

The South American continent also includes various island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

s, most of which belong to countries on the continent. The Caribbean

Caribbean

The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

territories are grouped with North America. The South American nations that border the Caribbean Sea — including Colombia

Colombia

, Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

, Guyana

Guyana

Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...

, Suriname

Suriname

Suriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...

, and French Guiana

French Guiana

French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

— are also known as Caribbean South America

Caribbean South America

Caribbean South America is a region of South America consisting of the nations that border the Caribbean Sea, namely:*Colombia*Venezuela...

Topography and geology

The geographical structure of South America is deceptively simple for a continent-sized landmass. The continent's topography is often likened to a huge bowl owing to its flat interior almost ringed by high mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

s. With the exception of narrow coastal plains on the Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

and Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

s, there are three main topographic features: the Andes

Andes

, a central lowland, and the extensive Brazilian

Brazilian Highlands

The Brazilian Highlands or Brazilian Plateau are an extensive geographical region, covering most of the eastern, southern and central portions of Brazil, in all approximately half of the country's land area, or some 4,500,000 km²...

and Guiana Highlands in the east.

The Andes are a Cenozoic mountain range formed (and still forming) by the continuing convergence of the American and Pacific tectonic plates. In their northern and central reaches the Andes are quite wide and contain extensive plateau

Plateau

In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...

such as the Altiplano

Altiplano

The Altiplano , in west-central South America, where the Andes are at their widest, is the most extensive area of high plateau on Earth outside of Tibet...

and a number of major valleys such as the Rio Magdalena. These contain three of the world's highest capitals: Bogotá

Bogotá

Bogotá, Distrito Capital , from 1991 to 2000 called Santa Fé de Bogotá, is the capital, and largest city, of Colombia. It is also designated by the national constitution as the capital of the department of Cundinamarca, even though the city of Bogotá now comprises an independent Capital district...

, Quito

Quito

San Francisco de Quito, most often called Quito , is the capital city of Ecuador in northwestern South America. It is located in north-central Ecuador in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains...

and highest of all, La Paz, Bolivia. The southern Andes have been eroded by the Patagonian Ice Sheet

Patagonian Ice Sheet

350px|thumb|right|Map showing the extent of the Patagonian Ice Sheet in the [[Strait of Magellan]] area during the [[last glacial period]]. Selected modern settlements are shown with yellow dots...

and are much lower and narrower. There are a number of large glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

s in the northern part, but from latitude 19°S

19th parallel south

The 19th parallel south is a circle of latitude that is 19 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America....

to 28°S

27th parallel south

The 27th parallel south is a circle of latitude that is 27 degrees south of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australasia, the Pacific Ocean and South America....

the climate is so arid that no permanent ice can form even on the highest peaks. Permafrost

Permafrost

In geology, permafrost, cryotic soil or permafrost soil is soil at or below the freezing point of water for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs and it may be in amounts exceeding the potential hydraulic saturation of...

, however, is widespread in this section of the Altiplano and continuous above 5600 metres (18,373 ft).

The climate of the coastal belt west of the Andes shows violent contrasts, including two of the world's wettest regions in the Colombian Chocó and southern Chile and the world's driest desert, the Atacama. This dry area is cooled by the Humboldt Current

Humboldt Current

The Humboldt Current , also known as the Peru Current, is a cold, low-salinity ocean current that flows north-westward along the west coast of South America from the southern tip of Chile to northern Peru. It is an eastern boundary current flowing in the direction of the equator, and can extend...

and upwelling

Upwelling

Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The increased availability in upwelling regions results in high levels of primary...

, giving rise to the largest fisheries in the world. There are two small transition zones between the perhumid and perarid regions: around Guayaquil

Guayaquil

Guayaquil , officially Santiago de Guayaquil , is the largest and the most populous city in Ecuador,with about 2.3 million inhabitants in the city and nearly 3.1 million in the metropolitan area, as well as that nation's main port...

with summer rain, and the Mediterranean climate

Mediterranean climate

A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...

region of central Chile. Both these regions have highly erratic rainfall strongly influenced by El Niño events, which bring major floods. In contrast, the high plateaux of the Andes are drier than normal during El Niño episodes.

The very fertile soils from the erosion of the Andes formed the basis for the continent's only pre-Columbian state civilization

Civilization

Civilization is a sometimes controversial term that has been used in several related ways. Primarily, the term has been used to refer to the material and instrumental side of human cultures that are complex in terms of technology, science, and division of labor. Such civilizations are generally...

s: those of the Inca Empire

Inca Empire

The Inca Empire, or Inka Empire , was the largest empire in pre-Columbian America. The administrative, political and military center of the empire was located in Cusco in modern-day Peru. The Inca civilization arose from the highlands of Peru sometime in the early 13th century...

and its predecessors (Chavín

Chavin

Chavin may refer to:* Chavín culture, an early culture of the Andean region, pre-dating the Moche culture in Peru* Chavín de Huantar, an archaeological site built by the Chavín culture* Chavin, Indre, a commune of the Indre département in France...

, Nazca

Nazca

Nazca is a system of valleys on the southern coast of Peru, and the name of the region's largest existing town in the Nazca Province. It is also the name applied to the Nazca culture that flourished in the area between 300 BC and AD 800...

, Mochica, etc.). The area is still a major agricultural region. The Altiplano contains many rare minerals such as copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, tin

Tin

Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...

, mercury ore

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

. The Atacama is mined for its nitrate

Nitrate

The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...

s. East of the Andes in Peru is regarded as the most important biodiversity

Biodiversity

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

hotspot in the world with its unique forests that form the western edge of the world's largest rainforest, the Amazon Rainforest

Amazon Rainforest

The Amazon Rainforest , also known in English as Amazonia or the Amazon Jungle, is a moist broadleaf forest that covers most of the Amazon Basin of South America...

.

East of the Andes is a large lowland drained by a small number of rivers, including the two largest in the world by drainage area - the Amazon River

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

and the more southerly Paraná River

Paraná River

The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...

. The other major river of this central lowland is the Orinoco River, which has a natural channel linking it with the Amazon. Most of this central lowland is sparsely populated because the soils are heavily leached, but in the south is the very fertile pampas of Argentina - one of the world's major food-producing regions where wheat and beef cattle

Beef cattle

Beef cattle are cattle raised for meat production . The meat of cattle is known as beef. When raised in a feedlot cattle are known as feeder cattle. Many such feeder cattle are born in cow-calf operations specifically designed to produce beef calves...

are pre-eminent. The natural vegetation of the northern lowlands are either savanna

Savanna

A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

in the northern llanos
Llanos
The Llanos is a vast tropical grassland plain situated to the east of the Andes in Colombia and Venezuela, in northwestern South America. It is an ecoregion of the Flooded grasslands and savannas Biome....

and southern campos, or tropical rainforest throughout most of the Amazon basin. Efforts to develop agriculture, outside of fertile floodplains of rivers descending from the Andes, have been largely failures because of the soils. Cattle have long been raised in the llanos of northern Colombia and Venezuela, but petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

is now the dominant industry in the northern lowlands, making Venezuela the richest country in the continent.

The eastern highlands are much older than the Andes, being pre-Cambrian in origin, but are still rugged in places, especially in the wet tepui

Tepui

A tepui , or tepuy, is a table-top mountain or mesa found in the Guiana Highlands of South America, especially in Venezuela. The word tepui means "house of the gods" in the native tongue of the Pemon, the indigenous people who inhabit the Gran Sabana....

s of Venezuela, Guyana and Roraima

Roraima

Roraima is the northernmost and least populated state of Brazil, located in the Amazon region. It borders the states of Amazonas and Pará, as well as the nations of Venezuela and Guyana. The population is 400,000 and the capital is Boa Vista...

. The Amazon River has cut a large valley through a former highland, and to the east is a relatively low plateau comprising the Nordeste and Southeast

Southeast Region, Brazil

The Southeast Region of Brazil is composed by the states of Espírito Santo, Minas Gerais, Rio de Janeiro and São Paulo. It is the richest region of the country, responsible for approximately 60% of the Brazilian GDP. São Paulo, Rio de Janeiro and Minas Gerais are three richest states of Brazil,...

regions of Brazil. In the north of this region is the arid sertão
Sertão
In Portuguese, the word sertão first referred to the vast hinterlands of Asia that Lusitanian explorers encountered. In Brazil, the geographical term referred to backlands away from the Atlantic coastal regions where the Portuguese first settled in South America in the early sixteenth century...

, a poor region consistently affected by extremely erratic rainfall, and the humid zona da mata, once home of the unique Atlantic Rainforest with many species not found in the Amazon, and now a centre for sugarcane

Sugarcane

Sugarcane refers to any of six to 37 species of tall perennial grasses of the genus Saccharum . Native to the warm temperate to tropical regions of South Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six metres tall...

. Further south, the main land use is coffee

Coffee

Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...

, while São Paulo

São Paulo

São Paulo is the largest city in Brazil, the largest city in the southern hemisphere and South America, and the world's seventh largest city by population. The metropolis is anchor to the São Paulo metropolitan area, ranked as the second-most populous metropolitan area in the Americas and among...

is the economic heart of the continent with its industry.

South of about Santa Catarina

Santa Catarina (state)

Santa Catarina is a state in southern Brazil with one of the highest standards of living in Latin America. Its capital is Florianópolis, which mostly lies on the Santa Catarina Island. Neighbouring states are Rio Grande do Sul to the south and Paraná to the north. It is bounded on the east by...

, the highlands fade out to low plains in Uruguay.

East of the Andes in Argentina, there are a number of rugged, generally dry lslands, the highest of which is the Sierra de Cordoba near the city of that name. Argentine Patagonia is a Paleozoic

Paleozoic

The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...

plateau now heavily dissected by rivers flowing from the Andes.

Territories

The largest country in South America by far, in both area and population, is Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. Regions in South America include the Andean States

Andean states

The Andean States are a group of nations in South America that are defined by sharing a common geography or culture such as the Quechua language and Andean cuisine which was primarily spread during the times of the Inca Empire, but also before and after it.Politically speaking, Argentina and Chile...

, the Guianas

The Guianas

The Guyanas or the Guianas refers to a region in north-eastern South America which includes the following three territories:* French Guiana, an overseas department of France;...

, the Southern Cone

Southern Cone

Southern Cone is a geographic region composed of the southernmost areas of South America, south of the Tropic of Capricorn. Although geographically this includes part of Southern and Southeast of Brazil, in terms of political geography the Southern cone has traditionally comprised Argentina,...

, and Eastern South America.

Name of territory, with flag Flag A flag is a piece of fabric with a distinctive design that is usually rectangular and used as a symbol, as a signaling device, or decoration. The term flag is also used to refer to the graphic design employed by a flag, or to its depiction in another medium.The first flags were used to assist...	Area (km²)	Population (July 2009 est.)	Population density (per km²)	Capital
Argentina Argentina Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...	2,766,890	40,913,584	14.8	Buenos Aires Buenos Aires Buenos Aires is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent...
Bolivia Bolivia Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...	1,098,580	9,775,246	8.9	La Paz La Paz Nuestra Señora de La Paz is the administrative capital of Bolivia, as well as the departmental capital of the La Paz Department, and the second largest city in the country after Santa Cruz de la Sierra... , Sucre Sucre Sucre, also known historically as Charcas, La Plata and Chuquisaca is the constitutional capital of Bolivia and the capital of the department of Chuquisaca. Located in the south-central part of the country, Sucre lies at an elevation of 2750m...
Brazil Brazil Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...	8,511,965	198,739,269	23.3	Brasília Brasília Brasília is the capital city of Brazil. The name is commonly spelled Brasilia in English. The city and its District are located in the Central-West region of the country, along a plateau known as Planalto Central. It has a population of about 2,557,000 as of the 2008 IBGE estimate, making it the...
Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	756,950	16,601,707	21.9	Santiago Santiago, Chile Santiago , also known as Santiago de Chile, is the capital and largest city of Chile, and the center of its largest conurbation . It is located in the country's central valley, at an elevation of above mean sea level...
Colombia Colombia Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...	1,138,910	45,644,023	40.1	Bogotá Bogotá Bogotá, Distrito Capital , from 1991 to 2000 called Santa Fé de Bogotá, is the capital, and largest city, of Colombia. It is also designated by the national constitution as the capital of the department of Cundinamarca, even though the city of Bogotá now comprises an independent Capital district...
Ecuador Ecuador Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...	283,560	14,573,101	51.4	Quito Quito San Francisco de Quito, most often called Quito , is the capital city of Ecuador in northwestern South America. It is located in north-central Ecuador in the Guayllabamba river basin, on the eastern slopes of Pichincha, an active stratovolcano in the Andes mountains...
Falkland Islands Falkland Islands The Falkland Islands are an archipelago in the South Atlantic Ocean, located about from the coast of mainland South America. The archipelago consists of East Falkland, West Falkland and 776 lesser islands. The capital, Stanley, is on East Falkland... (UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... )	12,173	3,140	0.26	Stanley Stanley, Falkland Islands Stanley is the capital and only true cityin the Falkland Islands. It is located on the isle of East Falkland, on a north-facing slope in one of the wettest parts of the islands. At the 2006 census, the city had a population of 2,115...
French Guiana French Guiana French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west... (France France The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France... )	83,534	221,500	2.7	Cayenne Cayenne Cayenne is the capital of French Guiana, an overseas region and department of France located in South America. The city stands on a former island at the mouth of the Cayenne River on the Atlantic coast. The city's motto is "Ferit Aurum Industria" which means "Work brings wealth"...
Guyana Guyana Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...	214,970	772,298	3.6	Georgetown Georgetown, Guyana Georgetown, estimated population 239,227 , is the capital and largest city of Guyana, located in the Demerara-Mahaica region. It is situated on the Atlantic Ocean coast at the mouth of the Demerara River and it was nicknamed 'Garden City of the Caribbean.' Georgetown is located at . The city serves...
Paraguay Paraguay Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...	406,750	6,995,655	17.2	Asunción Asunción Asunción is the capital and largest city of Paraguay.The "Ciudad de Asunción" is an autonomous capital district not part of any department. The metropolitan area, called Gran Asunción, includes the cities of San Lorenzo, Fernando de la Mora, Lambaré, Luque, Mariano Roque Alonso, Ñemby, San...
Peru Peru Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....	1,285,220	29,546,963	23.0	Lima Lima Lima is the capital and the largest city of Peru. It is located in the valleys of the Chillón, Rímac and Lurín rivers, in the central part of the country, on a desert coast overlooking the Pacific Ocean. Together with the seaport of Callao, it forms a contiguous urban area known as the Lima...
South Georgia and South Sandwich Islands South Georgia and the South Sandwich Islands South Georgia and the South Sandwich Islands is a British overseas territory and overseas territory of the European Union in the southern Atlantic Ocean. It is a remote and inhospitable collection of islands, consisting of South Georgia and a chain of smaller islands, known as the South Sandwich... (UK)	3,903	0	0	Grytviken Grytviken Grytviken is the principal settlement in the British territory of South Georgia in the South Atlantic. It was so named in 1902 by the Swedish surveyor Johan Gunnar Andersson who found old English try pots used to render seal oil at the site. It is the best harbour on the island, consisting of a...
Suriname Suriname Suriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...	163,270	481,267	2.9	Paramaribo Paramaribo Paramaribo is the capital and largest city of Suriname, located on banks of the Suriname River in the Paramaribo District. Paramaribo has a population of roughly 250,000 people, more than half of Suriname's population...
Uruguay Uruguay Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...	176,220	3,494,382	19.8	Montevideo Montevideo Montevideo is the largest city, the capital, and the chief port of Uruguay. The settlement was established in 1726 by Bruno Mauricio de Zabala, as a strategic move amidst a Spanish-Portuguese dispute over the platine region, and as a counter to the Portuguese colony at Colonia del Sacramento...
Venezuela Venezuela Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...	912,050	26,814,843	29.4	Caracas Caracas Caracas , officially Santiago de León de Caracas, is the capital and largest city of Venezuela; natives or residents are known as Caraquenians in English . It is located in the northern part of the country, following the contours of the narrow Caracas Valley on the Venezuelan coastal mountain range...

Climate

As part of the Hadley model of atmospheric circulation, the equator is characterised by the ascending branches of separate meridional cells, driven by intense insolation

Insolation

Insolation is a measure of solar radiation energy received on a given surface area in a given time. It is commonly expressed as average irradiance in watts per square meter or kilowatt-hours per square meter per day...

. The vertical convection

Convection

Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....

draws in air from the surrounding atmosphere, known as the trade winds. As these inwards flows of air converge they reduce horizontal wind speed, and as they rise, they form precipitation

Precipitation

Precipitation may refer to:* Precipitation , rain, sleet, hail, snow and other forms of water falling from the sky* Precipitation , the condensation of a solid from a solution during a chemical reaction...

. The vertical convection also results in a net export of heat and freshwater from the lower atmosphere into the troposphere

Troposphere

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass and 99% of its water vapor and aerosols....

This system is known as the ITCZ. The location of the ITCZ is centred on the areas of highest insolation, although it is more stationary over the oceans than landmasses.

In the Atlantic region, the ITCZ is clearly developed, and the spatial extent of the ITCZ reaches a minimum close to the equator

Equator

An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

during the boreal spring (March–May), while extending to a maximum of 10º–15ºN in late boreal

Boreal

Boreal may refer to*Boreal ecosystem**Boreal climate, the climate found in a region of boreal forests, and designated Dfc, Dwc or Dsc in the Köppen climate classification scheme.*boreal forest*Boreal forest of Canada*Boreal Bluet...

summer (August). No comprehensive theory for ITCZ formation and spatial variation has been validated, although several hypotheses have been proposed. Some studies advance ideas that describe one or more atmospheric cells over the equator, while others state that the position of the ITCZ depends on Ekman

Ekman

-People:*Carl Gustaf Ekman , Swedish politician*Carl Daniel Ekman , Swedish chemical engineer*Erik Leonard Ekman , Swedish botanist*Gösta Ekman , Swedish actor*Gösta Ekman Swedish actor...

pumping efficiency and moisture availability. Whichever hypothesis best represents the natural system, it is clear that the dynamics of the ITCZ are influenced by several other external climate systems. These include continental convection and equatorially asymmetric sea surface temperature (SST) distribution. This asymmetry is evident in the northward bias of the ITCZ´s location, which is maintained by a positive feedback

Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...

between wind speed, evaporation and SST.

Whereas the ITCZ has a global extent, South America is subject to its own unique climate patterns. which have been organised into the South American Monsoon System

Monsoon

Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...

(SAMS). As an integrated component in the global climate system, the SAMS is influenced the Atlantic sector of the ITCZ, variability in the adjacent Pacific and Atlantic Oceans, the Andean and central-east Brazil topography, complex land surface processes and relations with land use change, and interactions involving topography

Topography

Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...

and soil moisture. The SAMS framework comprises several distinct subcomponents, which are discussed below:

The Pacific and Atlantic subtropical high: These are semi-permanent high pressure systems caused by descending sectors of the equatorial Hadley cells. The air masses are relatively warm and dry, and move in an anticyclonic circulation pattern over the sub-tropical oceans. The Pacific High is generally stable, where as the Atlantic High moves throughout the year. During the summer, it covers most of the midlatitude and subtropical Atlantic Ocean. During winter, it is smaller and moves to the east.

The Gran Chaco thermal low: A semi-permanent thermal-orographic depression located over the slope extending from Chaco to the Los Andes mountain range in the Argentine Northwest. It can be considered, together with the Bolivian High, as the regional response of the tropospheric circulation to the strong convective heating over the Amazon–central Brazil. The Andes effect reinforces the strength of the Chaco Low as an orographic barrier. It is present throughout the year, but is more intense during the summer, with a strong thermal component caused by the combination of high insolation and dry surface conditions. The resulting pressure gradient between the south Atlantic subtropical high and the Chaco low forces the easterly winds over the Amazon basin to turn southward, being channelled between the eastern slope of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

and the Brazilian Plateau.

The South Atlantic Convergence Zone
South Atlantic convergence zone
The South Atlantic convergence zone, or SACZ, is an elongated axis of clouds, precipitation, and convergent winds oriented in a northwest-southeast manner across southeast Brazil into the southwest Atlantic ocean. By definition, the feature is a monsoon trough. It is strongest in the warm season...

(SACZ): The SACZ controls rainfall in the southern subtropics and extends southeastward from the large continental convective zone of tropical South America. It is generated by moisture convergence between the South Atlantic high pressure zone and the continental thermal low pressure zone. The location of the SACZ is influenced by the topography in central-east Brazil Vera et al. (2006). The intensity of the SACZ is highest in austral summer, in phase with intensifying continental heating and convection. Weak SACZ is accompanied by enhanced rainfall over northern Argentina and southern Brazil. These positive rainfall anomalies are supported by a strong southward moisture flux at about 35ºS– 60ºW that shifts eastward to about 40ºW for the opposite phase of the seesaw, in accordance with an eastward displacement of the Atlantic high. An intensified SACZ is associated with enhanced streamflows to the north and diminished flows to the south. This north-south separation is probably related to the anomalously warm sea surface temperatures (SSTs) over the tropical and subtropical South Atlantic that strengthens the low-level meridional temperature gradient, intensifying the South Atlantic High and consequently the trade-winds.

Polar outbreaks: Polar outbreaks occur when cold dense polar air masses pass beneath warmer tropical air masses, significantly cooling subtropical South America. They occur as a result of anticyclogenesis
Anticyclogenesis
Anticyclogenesis is the development or strengthening of anticyclonic circulation in the atmosphere. It is the opposite of anticyclolysis, and has a cyclonic equivalent—cyclogenesis. Anticyclones are alternatively referred to as high pressure systems. High pressure areas form due to downward...

in the Pacific subtropical high, which is constrained at a low level by the southern extent of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...

mountain range. This leads to the formation of a slow-moving long wave that creates mountain-parallel, ageostrophic flow, causing incursions of high-latitude cold air. They generate an important drop in temperature and increase in pressure, resulting in regional precipitation for southern South America. These surges occur mainly during the winter but their impact on the precipitation is even greater during summer.

Low Level Jet (LLJ): LLJs originate in a low pressure area over the northern Andes and provide moisture for subtropical latitudes. During summer, they operate as localised wind maximum within the lower 1-2km of the atmosphere, channelled by the Andes, terminating in southeastern South America. They area controlled by Amazonian wind patterns, which are in influenced by controlled by patterns of insolation. They transport large amounts of moisture from the Amazon basin to the monsoonal anitcyclone over Bolivia. A suppressed SACZ and increased convection in the sub-tropical plains is associated with a strengthening of the LLJ. These phases are linked to short-term extreme precipitation events in the plains of central Argentina. When the LLJ is weak, there is enhanced SACZ and suppressed convection to the south and extreme heat waves over the sub-tropical regions. It also generates turbulence through shear and participates actively as trigging mechanism for the formation of severe storm and Mesoscale Convective Systems over Paraguay, Northern Argentina and South of Brazil.

Westerlies: South America experiences westerly winds
Westerlies
The Westerlies, anti-trades, or Prevailing Westerlies, are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude, blowing from the high pressure area in the horse latitudes towards the poles. These prevailing winds blow from the west to the east, and steer extratropical...

in the middle latitudes, caused by the Coriolis
Coriolis
Coriolis may refer to:* Gaspard-Gustave Coriolis , French mathematician, mechanical engineer and scientist* Coriolis effect, the apparent deflection of moving objects from a straight path when viewed from a rotating frame of reference...

force and associated geostrophic circulation patterns. They are more intense than their Northern Hemisphere counterparts due to the lack of continental landmass in the Southern Hemisphere. They reach their maximum speed in the troposphere, where they form jetstreams. In particular, over the southern tip of South America and the adjacent south Pacific, the westerlies are strongest during austral summer, peaking between 45° and 55°S. During the austral winter, the jetstream
JetStream
JetStream and Mobile JetStream are two former brand names used by Telecom New Zealand to market its retail and resale ADSL-based fixed line and CDMA2000-based 3G wireless Internet access offerings respectively...

moves into subtropical latitudes (its axis is at about 30°S) and the low-level westerlies expand equatorward but weaken, particularly at ~50°S. The pressure gradients between the polar low-pressure belt and the Pacific high-pressure cell, combined with these westerlies, results in permanent anticyclogenesis. Northward penetration of atmospheric perturbations from the westerlies is possible when the southeast Pacific anticyclone is weakened or moves equatorward, allowing penetration of westerly storm tracks to latitudes as far north as 31◦S. In the Andes, winter rains reach further north. During summer, the Pacific anticyclone shifts southward, impeding the northward migration of the westerlies.

The Bolivian High: large anticyclonic circulation centred near 15°S, 65°W. It has been explained as the response of diabatic local heating in the Amazon region. The SACZ has a strong influence on the position and intensity of the Bolivian High

The Madden-Julian Oscillation
Madden-Julian oscillation
The Madden–Julian oscillation ' is the largest element of the intraseasonal variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection...

(MJO): The MJO is characterized by an eastward progression of large regions of both enhanced and suppressed tropical rainfall, observed mainly over the Indian Ocean and Pacific Ocean. It is a source of intra-seasonal variability affecting South America that seems to be related to a combination tropical circulation changes and midlatitude Rossby wave trains that propagate into South America.

The development of the SAMS during spring is characterised by a rapid southward shift of the convective region from northwestern South America to the highland region of the central Andes and to the southern Amazon basin. The South Atlantic High moves eastward, reflecting the pressure reduction over the continent and the intensity and direction of the zonal flow over the nearby tropics and sub-tropics. This change in flow direction is evident in changes to terrestrial windfields over extreme southwestern Amazonia, with winds changing from northerlies to northwesterlies, and over eastern Brazil, where the winds turn from easterlies to northeasterlies. The southward moisture flux east of the Andes also increases, bringing humidity to central and southeast Brazil.

As the SAMS progresses a continental-scale gyre

Gyre

A gyre in oceanography is any large system of rotating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis Effect; planetary vorticity along with horizontal and vertical friction, which determine the circulation patterns from the wind curl...

transports moisture westward from the tropical Atlantic Ocean to the Amazon basin and then southward toward the extratropics of South America. The diabatic

Diabatic

A diabatic process is one in which heat transfer takes place, which is the opposite of an adiabatic process. In quantum chemistry, the potential energy surfaces are obtained within the adiabatic or Born-Oppenheimer approximation...

heating released in the SAMS region seems to promote that gyre, and the maintenance of the South Atlantic subtropical high during austral summer. It has also been suggested that is the subsidence over the cool SSTs of the eastern Pacific and extensive stratocumulus decks provide a radiative heat sink to the tropical atmosphere that can balance the adiabatic warming due to the monsoonal descent.

The decay phase of the monsoon begins between March and May, as convection shifts gradually northward toward the equator. During April and May, the low-level southward flow of moisture from the western Amazonia weakens, as more frequent incursions of drier and cooler air from the mid-latitudes begin to occur over the interior of subtropical South America.

Topography and geology

Territories

Climate

See also