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This page is devoted to islands in the Caribbean and to the Latin countries of Central and South America. Vegetation cover ranges from desert to forested mountains to subtropical lowlands.


The Caribbean and Central and South America

The Caribbean is a broad geographic area that extends south and east of the Gulf of Mexico, and includes islands such as Cuba and Puerto Rico, a string of islands along a plate boundary called the Antilles (the West Indies reached by Columbus), and islands off the northern shores of South America. The Bahamas are generally included in this group. A view from space (mosaic) shows the eastern and southern Caribbean. The map covers the entire Caribbean from Florida to Venezuela:

Composite image of much of the Caribbean.

Map of the Caribbean.

The largest of the Caribbean islands is the nation of Cuba, seen in this MODIS image:

MODIS image of Cuba.

At the bottom of the above image is Jamaica. Here is a closer look contained in an astronaut photo:

Jamaica, as seen by the astronaut aboard the International Space Station.

Typical of the northern island are Puerto Rico and the Virgin Islands. The first image is an STS astronaut-taken photo of Puerto Rico, which by treaty is allied to the United States:

Puerto Rico, as seen from the Space Shuttle.

It is not obvious from this photo that the interior of Puerto Rico is mountainous. A DEM topographic image reveals the extent of these mountains:

Topographic color image of Puerto Rico constructed from Digital Elevation Map (DEM) data; lowlands appear in blue.

Puerto Rico contains the only true tropical rain forest in territories tied to the U.S. This view is from the El Yunque National Park:

The mountainous 'jungle' of eastern Puerto Rico.

San Juan is one of the oldest cities in the western hemisphere (Columbus discovered Puerto Rico in 1493). Here is a view of the old city in the foreground, the new city further back, and the western mountains in the distance.

Aerial view of San Juan.

In April, 2004 the writer and wife took a weeklong Carribean cruise that started and ended in Puerto Rico. One pasttime was to indulge in my hobby of birdwatching on each of the islands visited: St. Thomas, St. Kitts, Grenada, Isla Margarita, and Aruba (see map above). When we arrived at the ship's docking pier, as seen below, my plan was to travel the mile to the west tip of San Juan to the El Morro fortress (second image) in order to see a bird species found only there. I had three hours but walking was not feasible. I contacted several taxi drivers; none would take me through the old town because Sunday traffic was jammed and stalled and they could not guarantee return in time. A frustration - the classic "so near, yet so far".

The old town section of San Juan; IKONOS image

The El Morro fortress and park; enlarged IKONOs image.

A short distance to the east of Puerto Rico are the Virgin Islands, seen in this astronaut photo:

The Virgin Islands.

The left (west) two islands are U.S. territories, being the islands of St. Thomas and St. John (to its east). The large island in the middle is the British Virgin Island of Tortola.

The Lesser Antilles is a long chain of island that run from the Virgin Islands south to Grenada, then east through Trinidad to the Dutch islands of Curacao and Aruba. The Outer Antilles face the Atlantic Ocean, as seen here in this MODIS view:

The Antilles Islands (from the top) of Antigua, Montserrat, Dominica, Martinique, Santa Lucia, St. Vincent, and Grenada.

Typical of this eastern group, popular in winter with tourists looking for warm climes and dreamy beaches, in the Windward Islands is the volcanic island of Martinique:

Astronaut photo of Martinique.

The small island of Aruba, off the Venezuelan coast marks the end of the Antilles. This island, a semi-desert, has been photographed by the Shuttle astronauts:

Astronaut photo of Aruba, part of the Dutch Antilles.

We now head go westward across the Gulf of Mexico and move south of the U.S. border into northeast Mexico, in the States of Nuevo Laredo and San Luis Potosi (left two-thirds of the image below) and Tamaulipas (right). The strongly folded sedimentary rocks of the Sierra Madre Orientale run through the center of the scene. Coastal plains make up the area to the east and semi-desert at high elevations occupies the land to the west. The reds denote regions that can experience 30 inches (75 cm) of rainfall each year owing to moisture moving inland from the Gulf of Mexico. This is a monsoonal climate, with wet, hot summers and dry cold winters. The plains supports typical subtropical savannah vegetation and the mountains are havens of both broadleaf and coniferous trees. The arid interior to the west is host to brushy plants and cactus.

 Part of the Sierra Madre Orientale of northern Mexico, with rain forests to the east and a barren desert landscape in the lowlands to the west.

On to central Mexico and a peak at the oldest city in the Western hemisphere, the present day Mexico City, built on a site where in the 12th century stood Tenochitlan, inhabited continuously since then. Mexico City now is seen as a blue area in the upper left part of the image. In 1973, M.C. had just over 7 million but has grown so rapidly that it will approach 30 million early in the 21st Century. Parts of the city stand on swampy ground and lake beds, particularly susceptible to failure and building collapse during the strong earthquakes that frequent the region. To its east are a line of active to dormant volcanoes, marking the surface expression of subduction of the Pacific plate under the North American plate.The two biggest volcanoes are Istaccihuatl and Popocatepetl, both snow-capped in this May scene, that lie to the southeast of M.C. Their slopes, and highlands elsewhere, are forested (reds) but most of the land is arid and sparsely vegetated. Most of the region shown is elevated - at 2800 m (7500 ft) at M.C. and higher.

 Mexico City (blue area upper left), volcanic mountains, and desert lands in central Mexico.

This Landsat-7 subscene, acquired on March 21, 2000, shows the city in more detail

Landsat-7 ETM+ view or Mexico City.

Combining Landsat and DEM data yields this perspective view of Mexico City. The two volcanoes appear to its south-southeast. The ring of hills around much of Mexico City indicates why it is often a smog-drenched city since winds may be too blocked to drive the gases away.

Perspective view of Mexico City, made by combining Landsat and DEM data.

Compare this with the ground photo of this city of more than 20 million, with Popocatepetl in the background:

Part of Mexico City.>

We move into Central America through Guatemala into Nicaragua. Its western part, against the Pacific Ocean, appears below. The larger body of water inland is Lake Nicaragua, with several volcanoes on islands within. In the upper left is Lake Managua, with the capital city, Managua, along its south shore. Circular lakes are fillings of central vents or calderas. The lower elevations consist of semi-arid vegetation, with some farmlands. Areas of red represent uplands with forest cover, with more mountainous highlands at the upper right corner.

Western Nicaragua, in Central America. This scene shows the large Lake Managua and several volcanoes built on the strong folded rocks of the region.

This part of Central America, which includes Guatemala, Honduras, and El Salvador, is especially mountaineous, with its ranges marking the upthrown crustal blocks at a plate boundary. The relief map made from SRTM data bring out the rugged topography (note the fault lines that are etched out from the terrain):

SRTM relief map of part of Central America.

As we approach the South American continent, we move from Costa Rica into Panama, shown in another relief map created from SRTM data:

Relief map of southern Central America, made from Shuttle Radar Topography Mission data; the Panama Canal is not shown in this version but its course can be imposed using the next two images.

In the scene below, a Landsat-DEM perspective image we see the "Big Ditch" that was one of President Teddy Roosevelt's greatest accomplishments - the Panama Canal, which rivals the Suez Canal (see page 6-13) as the greatest aid in oceanic navigation.

Perspective  Landsat image of the Panama Canal.

Landsat data are displayed in colors that represent the calculated NDVI (Section 3) for the area that include the Canal and Lake Gatun. Most of the land on either side has a strong NDVI rating, expected since this is heavily forested tropical "Jungle".

The Panama Canal in a version made as an NDVI image using Landsat data.

Unlike the earlier Suez Canal, the Panama Canal requires a series of locks to acommodate the difference in sea level heights between the Atlantic (Gulf of Mexico) Ocean and the Pacific Ocean (the Pacific is about 5 meters higher). A boat enters a lock, behind it another lock gate swings shut, and water is pumped in to raise the boat level to that of the next lock entered. Here is a diagram of this lock system:

Cross-section through the Panama Canal, looking south, showing the individual locks in the water rising-lowering system.

Staying in the Caribbean but now touching the northern coast of South America, this next scene is an Envisat-MERIS image of parts of Venezuela and Columbia to its west:

MERIS (Envisat) image of northwest Venezuela and northeast Columbia (see text for more details).

The greenish water off the Caribbean is the Gulf of Venezuela. A narrow strait passes south into Lake Maracaibo, within and around which ar most of the oil fields that make Venezuela the fifth largest petroleum producer in the world. On its west side is the Sierra de Perija whose crest forms the border with Columbia. Along the eastern shore of Maracaibo is the Cordillera de Merida. Both mountain systems are the northern extension of the Andes. The west mouth of the Gulf of Venezuela is formed by the Guajira Peninsula. An island like body on the east side is the Paraguana Peninsula, joined to the mainland by such a narrow strip of land as to be almost invisible in this image. Just above the peninsula in the center is Aruba, shown above. The island of Curacao (famed for its liqueur of that name, made from sour orange peels, and as a stop for Caribbean cruise ships) lies to its east. Caracas, the Venezuelan capital, is just off the image on the upper right side.

Our travels next take us through representative parts of South America. This map shows the countries making up this continent and the major geographic land units.

The main geopolitical units of South America.

We'll start along the west coast of South America. The dominant landform features in western South America are the mighty Andes Mountains. These are part of the general cordillera that lines the western regions in both Americas and Central America. The Andes are uplifted mountains, involving intense folding, faulting, and volcanism on the continental tectonic plate as it is subducted by the east moving, incoming Pacific tectonic plate. JPL has prepared a simulated journey along the Andes as a movie using radar data. Access it through the JPL Video Site, then the pathway Format-->Video -->Search to bring up the list that includes "Andes Mountains Flyover", June 20, 2003. To start it, once found, click on the blue RealVideo link.

In this Landsat-1 image in southern Peru, a dry desert appears blue. The land rises abruptly eastward in dissected mountains whose elevations range to altitudes from 4300 to 5500 meters (14000 to 18000 ft; the highest peaks in the Andes approach 23000 ft). Progressing to the northeast, the terrain is first dissected, then gives way to a broad, flatter Altiplano, and ends (upper right) in the High Andes.

Part of the Peruvian Andes; Landsat-1, April 29, 1974.

The highest peak in the South American Andes is Cerro (mountain) Aconcagua (6982 m or 22840 ft) in Argentina, shown in this Landsat-5 image:

Mt Aconcagua, Argentina

The next view covers a very sparsely populated segment of southern Peru (top) and northern Chile. The bluish-gray stretch of lands from the coast inward in part of the Atacama Desert, notorious as one of the driest regions on Earth. The desert results from the "drying out" of moisture in air masses crossing the Andes, which leds to rains and heavy snows. Some places in this desert, which continues well to the south, have seen as little as 1 inch of rain in five years. But, note that a few river valleys have ribbons of red indicating some vegetation (in oases where small villages can subsist), fed by occasional water coming from the better water uplands of the volcanic Cordillera Occidentale that comprises the western extent of the Andes. (See if you can find the large volcano in this image.) Note the landforms against the Andes flanks which are yellowish-brown - these are huge, coalesced alluvial fans now being dissected.

The West Coast of South America, with the border between Peru and Chile shown; the edge of the Andes is on the right side; the blue area is part of the Atacama Desert, which includes the driest area in the world; Landsat-1; March 25, 1975.

The desert is replaced by vegetation (some cultivated) in the lowlands extending inward from the Pacific. In this Landsat-7 ETM+ image, Chile's capital of Santiago appears as a dark-gray area in the green valley surrounded by coastal ranges to the west and the Andes to the east.

Moving across the Andes, Western Argentina occupies the scene below. Along the left margin is the eastern terminus of the High Andes, with ridges above 4800 meters (16000 ft), and surface with few extended forests but with some brushy vegetation. A large alluvial fan, in blue, appears near the upper left; at its eastern (right) margin is a conspicuous area of red-rendered vegetation which marks a zone where subsurface and surface waters from snow melt in the Andes passes onto the high plains. Lake Ilancanedo is seen to its southeast, a body of water that varies considerably with the seasons (in March, for this scene, the southern Fall is drier and the lake has shrunk). The landscape at this time of year shows minimum active plant growth. The volcano Cerro Nevado, with its snow cover giving the clue that it is high (3700 m; 12000 ft), seems isolated from the Andes. The caldera topping Cerro Payun (near bottom center) lies east of a broad field of basaltic volcanism.

Western Argentina: the east edge of the Andes is on the left; the lower lands to its right are mostly volcanic in nature (flows).

Using a combination of a Landsat image and SRTM elevation data, a perspective of the Andes in Argentina gives an impression of their great heights:

Perspective oblique view looking west of the High Andes in Argentina; SRTM-Landsat composite.

The Andes are a relatively young mountain system. The eastward subduction of the Pacific plate leads to extensive melting that produces numerous volcanoes (as reported on page 17-3). These lie along the Pacific Ring of Fire. This SIR-C image shows several in northern Ecuador, including the trio Cuan, Mojande, and Imabua, and to their south, Cayambe.

Andean volcanoes in Ecuador.

Much of southern Argentina that includes the Andes is called Patagonia. These mountains support numerous mountain glaciers, such as the three in the scene below. The SIR-C pair were taken during the southern Spring and Fall and show (as indicated by color differences) both variation in glacial ice and in seasonal vegetation:

SIR-C images of Patagonia's mountains and glacier.

Buenos Aires, Argentina's capital, has been called the "Paris of South America" because of its bright, clean buildings (despite a Shanty Town within its limits) and planned layout. This city of 11 million lies on the Rio Plata's estuary; to its north is Uruguay. Let's first look at its skyline:

The Skyline of Buenos Aires.

Here is a 15 m Landsat-7 ETM image of the region, including the north end of the Pampas (plains land noted for its favored grazing of beef cattle):

Landsat-7 ETM+ image of Buenos Aires and surroundings.

Part of the central city as seen at 4 meters by IKONOS shows the rectangular block layout of Buenos Aires:

IKONOS image showing some of central Buenos Aires.

Rio de Janeiro, the Queen city of Brazil, spreads out from the western shore of Guanabara Bay, along the coast (the city, in black, lies above center right) as seen in this Landsat 2 image. The low Serra do Mar passes through this area. The Serra de Orgaos, up to 1000 m (3000 ft) lies to the north. Similar low mountain terrain extends to the west. An evergreen rain forest lines the coast but mixes with semideciduous and mountain vegation further inland. Note the narrow strip of land (near image center) made up of marine deposits that encloses the Baia de Sepetiba. Brazilís second city, Sao Paulo, is situated on the coast in the next westward Landsat orbit below the lower left corner of this scene.

The heavily wooded southern coast of Brazil; Rio de Janiero is situated on a bay near the right edge of this Landsat image.

This Landsat-7 ETM+ image shows much more detail within Rio de Janiero:

Rio de Janeiro and surroundings, imaged by Landsat-7

This astronaut photo from STS61 shows much the same area but with several landmarks labeled on the scene:

Rio de Janiero as photographed from the International Space Station

This city is the jewel of South America (although many who visit Buenos Aires would quibble with this statement). This ground photo shows only part of the area of high rises set against the background of the Bahia Guanabara and the famed Sugarloaf mountain with its tall statue of Christ with arms outstretched:

Part of Rio de Janeiro.

We have shown the inland pampas of Brazil as seen at Brasilia, the capital of Brazil on page 4-4. We repeat its coverage, using an astronaut photo from mission STS-38.:

Astronaut false color photo of Brazilia.

The government buildings in Brazilia are laid out in a broad expanse of open space:

Government buildings in the Federal City of Brazilia.

Brazilia lies near the edge of the great drainage basin controlled by the Amazon River. Much of the basin is lowlands and is heavily forested but many of its rivers start on the eastern flank of the Andes and other areas of higher elevation. This map zeroes in on the main drainage elements of the Amazon Basin.

The Amazon Basin

If one moves further north into the tropical forest of the Amazon basin, the denseness of the jungle where not clearcut is truly amazing (see page 3-5). Here is another aerial oblique photo of the Amazon as it flows through the eastern lowlands. Beneath it is an example of what usually comes first to the writer's (NMS) mind when the Amazon jungle is mentioned.

Aerial view of the Amazon jungle.

The Emerald Tree boa constrictor.

Considering the vast density of jungle vegetation in the Amazon, it seems astounding that a major city of 1.2 million people has been carved out of the wilderness at the junction of the Amazon and Rio Negro Rivers. This is Manaus, shown in an astronaut photo and in a quasi-natural color ASTER image made from the Terra satellite:

Astronaut photo of Manaus, Brazil; STS-61; the image would have to be rotated at about a 45 degree clockwise angle from the vertical to orient it with north aligned with the vertical.

The modernity of this expanding urban area is suggested in this aerial oblique view:

Central Manaus, including the Opera House.

The sharp difference in the color of each river is brought out in this false color Landsat subscene; the blue marks strong reflectance in that spectral range by the great load of sediment in the ' Amazon:

The blue-colored Amazon meeting the black Rio Negro near Manaus, Brazil; Landsat image.

The Amazon is one of the two longest rivers on Earth. It carries a tremendous load of sediment - largely contributed from the higher elevations in the basin. Three million tons of particulates are carried into the Atlantic Ocean each day. The mouth of the Amazon is some 380 km (207 miles) wide; note in the map of the basin above that the drainage area has actually constricted to a narrow zone on the east. Below are a Terra MISR image of the mouth region, with the sediment in brown, and a Landsat-1 image (fit it into the upper image) that shows just a part of the vast spread of sediment through the mouth. Much of the land around the mouth is actually part of the delta being constructed by the Amazon.

MISR image of the Amazon's mouth.

Landsat-1 false color composite image of the sediment within the mouth of the Amazon.

Lastly, lest we overlook this fact: in a loose sense South America extends some 500 miles (800 km) into the Pacific Ocean (in reality, beyond the western edge of this continental plate). Ecuador "owns" the famous Galapagos Islands which we have or will encounter elsewhere in this Tutorial. Here is an astronaut photo from the International Space Station of part of the Galapagos - volcanic islands all - covering most of Isla Isabela and Isla Fernandino:

Several of the Galapagos Islands, made famous by Charles Darwin; ISS photo.

But now let's leave the western hemisphere to head east and cross the Atlantic Ocean.

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Primary Author: Nicholas M. Short, Sr. email: nmshort@ptd.net