~ Mother Earth ~

last SG · 2005-03-28T01:23:34+00:00

Celtic Sea The Celtic Sea (Irish: An Mhuir Cheilteach) is the area of the Atlantic Ocean off the south coast of Ireland. It is bounded to the east by Saint...

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Qatif Project

Saudi Aramco's Qatif Project, the largest crude increment built in recent times, adds 650,000 barrels (103,000 m³) per day to the 150,000 barrels (24,000 m³) per day already produced from the Abu Sa'fah field. At 800,000 barrels (127,000 m³) per day, Qatif becomes worlds largest crude production facility. In addition, it produces 370 million standard cubic feet (10,000,000 m³) per day of associated gas and 40,000 barrels (6,000 m³) per day of high-value condensate. No single project has ever pumped 800,000 barrels (127,000 m³) per day of crude oil, all at once into the global energy markets.

The Qatif and Abu Sa'fah fields

The Qatif field, north of Dhahran and not far from Ras Tanura, amounts to more than 500 square kilometres, including northern and southern dome structures. The onshore component of the project will provide 500,000 barrels (80,000 m³) per day of Arabian Light Crude barrels per day of Arabian Medium.

The project which took three million man-hours to design and 70 million man-hours to construct, brought with it the latest technological advancements to increase operational efficiency as well as environmental safety, from an onshore smokeless flare system to a new, 99% effective sulfur recovery system at Berri Gas Plant that uses technology to make it the cleanest operating plant of all Saudi Aramco facilities.

Production

* 800,000 barrels (127,000 m³) of crude oil per day.
* 370 million cubic feet (10,000,000 m³) of associated natural gas per day.
* 40,000 barrels (6,000 m³) of high-value hydrocarbon condensate per day.
* 1,800 metric tons of sulfur per day.

Issue #170

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Paunsaugunt Plateau

The Paunsaugunt Plateau (pronounced "PAWN-suh-gant") is dissected plateau, rising to an elevation of 7,000 ft-9,300 ft (2,100 m-2,800 m), in southwestern Utah in the United States. Located in western Garfield County, it is approximately 10 mi (16 km) wide, and extends southward from the Sevier Plateau approximately 25 mi (40 km), terminating in the Pink Cliffs at the southern end.

Paunsaugunt Plateau

It is drained by the East Fork Sevier River which flows northward on the plateau, to the meet the main branch (Sevier River) which flows in a valley along the western side of the plateau. The plateau is highly dissected along the eastern flank, which is drained by the Escalante River in the Colorado River watershed, and is protected as Bryce Canyon National Park. The plateau essentially marks the southeastern extreme of the Great Basin. Much of the plateau is part of Dixie National Forest.

Geologically the plateau was created approximately 10-15 million years ago by an uplift on the larger Colorado Plateau. The uplifting caused the formation of joints along the side of the plateau. Susequent erosive forces, especially along the eastern side in Bryce Canyon National Park, have resulted in the creation of strange rock formations called hoodoos which are the hallmark of the park.

The plateau receives approximately 200 in (500 cm) of snow per year and experiences approximately 200 days of freeze-and-thaw cycles.

Utah's Highway 12, an All-American Road, climbs to the top of the Paunsaugunt Plateau.

Issue #171

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David Livingstone

David Livingstone (March 19, 1813 May 1, 1873) was a Scottish missionary and explorer of the Victorian era, now best remembered because of his meeting with Henry Morton Stanley which gave rise to the popular quotation, "Dr. Livingstone, I presume."

David Livingstone

Early life

Livingstone was born in the village of Blantyre, South Lanarkshire, Scotland and first studied medicine and theology at the University of Glasgow. While working in London, he emulated the example of another Scot, Robert Moffat, and joined the London Missionary Society, becoming a minister.

From 1840 he worked in Bechuanaland (now Botswana), but was unable to make inroads into South Africa because of Boer opposition. It was during this time that Livingstone made the one convert that he ever made in Africa, who then renounced Christianity within six months. He married Robert Moffat's daughter Mary in 1844, and she travelled with him for a brief time at his insistence, despite her pregnancy and the protests of the Moffats. She later returned to England with their children.

Discovery of Victoria Falls

In the period 185256, he explored the interior, discovering Victoria Falls (which he named after his monarch, Queen Victoria). Livingstone was one of the first Westerners to make a transcontinental journey across Africa. The purpose of his journey was to open trade routes, while accumulating useful information about the African continent. In particular, Livingstone was a proponent of trade and missions to be established in central Africa.

David Livingstone memorial at Victoria Falls

At this time he believed the key to achieving these goals was the navigation of the Zambesi River. He returned to England to try to garner support for his ideas, and to publish a book on his travels. At this time he resigned from the missionary society to which he had belonged.

Zambesi Expedition

Livingstone returned to Africa as head of the Zambesi Expedition. While Livingstone was exploring the Zambesi river, the missions sent to central and east Africa at his urgings ended in disaster, with nearly every missionary dying of malaria or other ailments. The Zambesi river turned out to be completely unnavigable past the Kabrabasa rapids, a series of cataracts and rapids that Livingstone had failed to explore on his earlier travels.

The other Westerners, including Livingstone's brother Charles (the one exception being George Rae, an engineer) either died, resigned, or were fired by Livingstone. His wife Mary died on April 29, 1863 of dysentery, but Livingstone continued to explore, eventually returning home in 1864. The Zambesi Expedition was castigated as a failure in many British newspapers of the time, and Livingstone experienced great difficulty in raising funds to further explore Africa.

Source of the Nile

In March 1866, Livingstone returned to Africa, this time to Zanzibar (now part of Tanzania), where he set out to seek the source of the Nile. Richard Francis Burton, John Hanning Speke, and Samuel Baker had earlier (and correctly) identified either Lake Albert or Lake Victoria as the source, but the matter was still debated vigorously. Finding the Lualaba River, which feeds the Congo River, Livingstone decided that this river was in fact the "real" Nile.

Illness and death

He was taken ill, and completely lost contact with the outside world for six years. Only one of his 44 later dispatches made it to Zanzibar. Stanley, who had been sent in a publicity stunt to find him by the New York Herald newspaper in 1869 found Livingstone in the town of Ujiji, on the shores of Lake Tanganyika in 1871. Stanley joined Livingstone, and together they continued exploring the north end of the Tanganyika (the other constituent of the present Tanzania), until Stanley left the next year.

Despite Stanley's urgings, Livingstone was determined not to leave Africa until his mission was complete, and he died there, in Zambia, in 1873 from malaria and internal bleeding caused by bowel obstruction. His body, carried over a thousand miles by his loyal attendants Chuma and Susi, was returned to Britain for burial in Westminster Abbey.

Issue #172

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Lake Wanapitei

Lake Wanapitei is a meteor crater lake in Greater Sudbury, Ontario, Canada. It is located near the large Sudbury meteor crater but not related to it. It is 7.5 km in diameter and the age is estimated to be 37.2 ± 1.2 million years, placing it in the Eocene.

The Wanapitei crater is the water-filled structure (Lake Wanapitei) in this image that also includes the oval Sudbury crater.

The partially circular lake-filled structure on the right (east) is the 8 km (5 mi) wide Wanapitei crater, estimated to have formed 34 million years (m.y.) ago. The far larger Sudbury structure appears as a pronounced elliptical pattern, more strongly expressed by the low hills to the north. This huge impact crater, with its distinctive outline, was created about 1800 m.y. ago. Some scientists argue that it was at least 245 km (152 mi) across when it was circular. The strong northwestward thrusting of the Grenville Province terrane against the Superior Province (containing Sudbury) subsequently deformed it, more than 900 m.y. later, into its present elliptical shape (geologists will recognize this as a prime example of the "strain ellipsoid") model. After Sudbury was initially excavated, magmas from deep in the crust invaded the breccia filling, to emplace against its walls. Some investigators think that the resulting norite rocks are actually melted target rocks. This igneous rock is host to vast deposits of nickel and copper, making this impact structure a multi-billion dollar source of ore minerals. Source: NASA

Lake Wanapitei, a popular recreational and residential lake in the Sudbury area, is the largest lake in the world completely contained within the boundaries of a single city. The Wanapitei River flows through the lake. There is a provincial park located on the north shore of Lake Wanapitei; this is a non-operating park so there are no facilities.

The lake's name comes from the Ojibwa word Wahnabitaybing, or "tooth", which describes its shape. A nearby community which takes its name from the river is spelled Wahnapitae. However, the Wanapitei spelling is correct for both the lake and the river.

Issue #173

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Hauraki Gulf

The Hauraki Gulf is a coastal feature of the North Island of New Zealand. The gulf lies between Auckland, the Coromandel Peninsula, and the Hauraki Plains.

A true-colour image showing Auckland city (left), the Hauraki Gulf (centre) and the Coromandel Peninsula (right). The scene was acquired by NASA's Terra satellite, on October 23, 2002.

Sheltered location

The waters of the gulf are part of the Pacific Ocean, which it connects to in the north and east. The gulf is largely protected from the Pacific by Great Barrier Island and Little Barrier Island to the north, and by the 80 kilometre long finger of land that is the Coromandel Peninsula to the east.

Three large channels join the gulf to the Pacific: The Colville Channel lies between the Coromandel Peninsula and Great Barrier, the Cradock Channel lies between the two islands, and the Jellicoe Channel lies between Little Barrier Island and the coast of the North Auckland Peninsula.

To the north of Auckland several peninsulas jut into the gulf, notably the Whangaparaoa Peninsula. Kawau Island is located close to this peninsula.

Islands

In the west of the gulf lie a string of islands guarding the mouth of the Waitemata Harbour, one of Auckland's two harbours. These include Ponui Island, Waiheke Island and the iconic dome of Rangitoto Island (a dormant volcano), which is connected to the much older Motutapu Island by a causeway. The islands are separated from the mainland by the Tamaki Strait and Rangitoto Channel.

Other islands located in the gulf include Browns Island, Motuihe Island, Pakihi Island, Pakatoa Island, Rakino Island, and Rotoroa Island in the inner gulf, around Waiheke and Rangitoto; Motukawao Islands and Whanganui Island in the lee of the Coromandel Peninsula; and Channel Island and Tiritiri Matangi Island in the outer gulf.

The Firth of Thames

At the southern end of the Hauraki Gulf is the large pool known as the Firth of Thames. Beyond this lie the Hauraki Plains, formed by the Waihou/Thames River and the Piako River. The Hunua Ranges and hills of the Coromandel Peninsula rise on either side of the plains.

Beaches

Numerous beaches dot the shores of the gulf, notably at Duders Beach, Kawakawa Bay, Maraetai, and Orere Point.

Issue #174

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Arthur's Pass

Arthur's Pass is an alpine crossing of the Southern Alps of the South Island of New Zealand. It is at a height of 920 metres above sea level, and marks part of the boundary between Westland and Canterbury, 140 kilometres from Christchurch and 95 kilometres from Greymouth. The pass lies in a saddle between the valleys of the Otira River, a tributary of the Taramakau in the west and the Bealey River in the east.

Arthur's Pass

The pass is named after Sir Arthur Dudley Dobson, who led the first party of Europeans across the pass in 1864. He had been informed of the presence of a pass which had been used occasionally by Maori hunting parties by a West Coast Maori Chief, Tarapuhi. It is also believed that writer and explorer Samuel Butler had seen the pass several years earlier, but was unable to explore it at that time.The timing was perfect, as the West Coast was soon to be hit by a goldrush, and easy access to the Tasman's coast became imperative.

State Highway 73 passes over Arthur's Pass and is the highest of only three roads crossing the Southern Alps, the other crossings being the Haast Pass and Lewis Pass.

Previously prone to be blocked by landslides or avalanches, the road on the western side of the pass has seen extensive civil engineering work in the late 1990s. Most notably, the Otira Viaduct, near the settlement of Otira and spanning 440 meters of unstable terrain, was completed in 1999.

Arthur's Pass Village, a hamlet about 5 km south of the pass, is a popular base for exploring Arthur's Pass National Park.

Arthur's Pass Village

Issue #175

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Osaka Castle

Osaka Castle (Osaka-jo) is a castle in Chuo-ku, Osaka, Japan. Originally called Ozakajo, it is one of Japan's most famous castles, and played a major role in the unification of Japan during the sixteenth century.

Osaka Castle

The castle is situated on a plot of land roughly one kilometer square. It is built on two raised platforms of landfill supported by sheer walls of cut rock, each overlooking a moat. The central castle building is five stories on the outside and eight stories on the inside, and built atop a tall stone foundation to protect its occupants from sword-bearing attackers.

History

* 1583: Toyotomi Hideyoshi commenced construction on the site of the Ikko-ikki temple of Ishiyama Honganji. The basic plan was modeled after Azuchi Castle, the headquarters of Oda Nobunaga. Toyotomi wanted to build a castle that mirrored Oda's, but surpassed it in every way: the plan featured a five-story main tower, with three extra stories underground, and gold leaf on the sides of the tower to impress visitors.

* 1585: Inner donjon completed. Toyotomi continued to extend and expand the castle, making it more and more formidable to attackers.

* 1598: Construction completed. Hideyoshi died. Osaka Castle passed to his son, Toyotomi Hideyori.

* 1603: Tokugawa Ieyasu defeated Hideyori's armies at the Battle of Sekigahara, and started his own bakufu in Edo.

* 1614: Tokugawa attacked Hideyori in the winter. Although the Toyotomi forces were outnumbered 2 to 1, they managed to fight off Tokugawa's 200,000-man army and protect the castle's outer walls. However, Tokugawa attempted to muzzle Toyotomi by filling up the castle's outer moat, rendering it largely defenseless.

* 1615: During the summer, Hideyori began to dig the outer moat once more. Tokugawa, in outrage, sent his armies to Osaka Castle again, and routed the Toyotomi men inside the outer walls on June 4. Osakajo fell to Tokugawa, and the Toyotomi clan perished.

* 1620: The new heir to the shogunate, Tokugawa Hidetada, began to reconstruct and rearm Osaka Castle. He built a new elevated main tower, five stories on the outside and eight stories on the inside, and assigned the task of constructing new walls to individual samurai clans. The walls built in the 1620's still stand today, and are made out of interlocked granite boulders with no mortar whatsoever: they are held together solely by each other. Many of the stones were brought from rock quarries in the Seto Inland Sea, and bear inscribed crests of the various families who laid them into the walls.

* 1665: Lightning strikes burned down the main tower.

* 1843: After decades of neglect, the castle got much-needed repairs when the bakufu collected money from the people of the region to rebuild several of the turrets.

* 1868: Much of the castle was burned in the civil conflicts surrounding the Meiji Restoration. Under the Meiji government, Osaka Castle was converted to a barracks for Japan's rapidly-expanding Western-style military.

* 1928: The main tower was restored after the mayor of Osaka concluded a highly successful fund-raising drive.

* 1945: Bombing raids on Osaka damaged the reconstructed main tower.

* 1995: Osaka's government approved yet another restoration project, with the intent of restoring the main tower to its Edo-era splendor.

* 1997: Restoration was completed.

Today

The castle is open to the public, and is easily accessible from Osakajo Koen Station on the JR Osaka Loop Line. It is a popular spot during festival seasons, and especially during the cherry blossom bloom, when the sprawling castle grounds are covered with food vendors and taiko drummers.

The grounds also house a museum, convention hall, and the Toyokuni Shrine dedicated to Toyotomi Hideyoshi.

Issue #176

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Borneo

Borneo (politically divided between Indonesia, Malaysia and Brunei) is the third largest island in the world. It has an area of 743,330 km² (287,000 mi²), and is located at the centre of the Malay archipelago and Indonesia. Borneo is considered part of the geographic region of Southeast Asia.

Borneo and Sulawesi

Geography

Borneo is surrounded by the South China Sea to the north and northwest, the Sulu Sea to the northeast, the Celebes Sea and the Makassar Strait to the east, and the Java Sea and Karimata Strait to the south.

To the west of Borneo are the Malay Peninsula and Sumatra. To the south is Java. To the east are Sulawesi (Celebes) and the Moluccas. To the northeast are the Philippines.

Borneo's highest point is Mount Kinabalu in Sabah, with an elevation of 4,095 m above sea level.

Satellite photo of Borneo.

Administration

Borneo is divided politically into:

* The Indonesian provinces of East, South, West and Central Kalimantan.
* The Malaysian states of Sabah and Sarawak.
* The independent sultanate of Brunei in two parts.

History

The whole Borneo was controlled by Brunei Empire during its golden age from the 15th to 17th centuries.

Borneo was the main site of the confrontation between Indonesia and Malaysia between 1962 and 1966.

Natural resources

The island historically had extensive rainforest cover, but the area is shrinking rapidly due to heavy logging for the needs of the Malaysian plywood industry and also multinational companies such as Mitsubishi take their share. One half of the annual tropical timber acquisition of the whole world comes from Borneo. Furthermore, palm plantations are rapidly encroaching on the last remnants of primary rainforest. The rainforest was also greatly destroyed due to the forest fires in 1997 to 1998 which were started by man and coincided with an exceptional drought season of El Niño. During the great fire, hotspots could be seen on satellite images and a haze was created that affected Brunei, Malaysia, Indonesia and Singapore. The remaining Borneo rainforest is the only natural habitat for the endangered Bornean orangutan. It is also an important refuge for many endemic forest species, and the Asian Elephant, the Sumatran Rhinoceros and the Clouded Leopard.

In order to combat overpopulation in Java, the Indonesian government started a massive migration of poor farmers to Borneo, called transmigrasi to farm the logged areas, albeit with little success as the fertility of the land has been removed with the trees and what soil remains is washed away in tropical downpours.

Indigenous people (e.g. Kayan, Kenyah, Punan Bah and Penan) living on the island have been fighting for decades for their rights to preserve their environment against loggers and transmigrasi settlers.

The type of rainforests found in Borneo include rare peat-swamp forests and heath forest.

Issue #177

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Permafrost

In geology, permafrost or permafrost soil is soil that stays in a frozen state for more than two years in a row.

The extent of permafrost can vary as the climate changes. Today, approximately 20% of the Earth's land mass is covered by permafrost (including discontinuous permafrost) or glacial ice. Seasonal frost commonly overlays permafrost and is called the active layer as it will thaw during the summer. Plant life can be supported only within the active layer because growth can occur only in soil that is fully thawed for some part of the year. Thickness of the active layer varies by year and location but is typically 0.6 - 4 m (2 to 12 feet) thick. The depth of the permafrost can in areas of continuous permafrost and harsh winters be very great (440 m (1,330 feet) at Barrow, Alaska and as much as 1,493 m (4,510 feet) in the northern Lena and Yana River basins).

An ice wedge in permafrost.

Continuous and discontinuous permafrost

Permafrost will form in any climate where the mean annual air temperature is less than the freezing point of water - unless there is sufficient snowfall to form glaciers or ice sheets. Typically the temperature of the ground will be on average less variable from season to season than the air temperature, and temperatures also tend to increase with depth. Thus, if the mean annual air temperature is only slightly below 0°C (32°F), permafrost will form only in spots that are sheltered - usually with a northerly aspect. This creates what is known as discontinuous permafrost. Usually, permafrost will remain discontinuous in a climate where the mean annual temperature is between -5 and 0°C (23 to 32°F). There are exceptions in unglaciated Siberia and Alaska where the present depth of permafrost is a relic of climatic conditions during glacial ages where winters were up to 11°C (20°F) colder than those of today. At mean annual temperatures below -5°C (23°F) the influence of aspect can never be sufficient to thaw permafrost and a zone of continuous permafrost forms.

A line of continuous permafrost in the Northern Hemisphere is formed from the furthest-northward points at which permafrost sometimes melts or is interrupted by regions without permafrost; north of this line all land is covered by permafrost or glacial ice. The "line" of continuous permafrost lies further north at some longitudes than others and can gradually move northward or southward due to regional climactic changes. In the southern hemisphere, most of the equivalent line would fall within the Southern Ocean if there were land there; most if not all of the Antarctic continent is covered not with frozen soil but with glacial ice.

Construction on permafrost

Building on permafrost is difficult due to the heat of the building (or pipeline) melting the permafrost and sinking downwards. This sinking problem has three common solutions: using foundations on wood piles, building on a thick gravel pad (usually 1 to 2 m (4 to 6 feet) thick), or using anhydrous ammonia heat pipes. The Trans-Alaska Pipeline System uses insulated heat pipes to keep the pipeline from sinking into the permafrost.

At the Permafrost Research Institute in Yakutsk, it has been found that sinking of large buildings into the frozen earth (known to the Yakuts before Yakutsk was even founded) can be prevented effectively by means of stilts extended down to a depth of about fifteen metres or more. At this depth the temperature does not change with the seasons but remains at about -5°C.

Permafrost extent

Measurement of the depth and extent of permafrost may be an indicator of global warming as recent years (1998 and 2001) have seen record thawing of permafrost in Alaska and Siberia. In the Yukon, the zone of continuous permafrost has moved 100 kilometres poleward since 1899. However accurate records only go back 30 years. It is thought that the thawing of permafrost could exacerbate global warming through the release of methane and other hydrocarbons which are powerful greenhouse gases. It also could encourage erosion because permafrost lends considerable stability to the barren slopes in the Arctic.

Polygons on the ground.

At the Last Glacial Maximum, continuous permafrost covered a much greater area than it does today, covering all of ice-free Europe south to about Szeged and the Sea of Azov (then dry land) and China south to Beijing. In North America, only an extremely narrow belt of permafrost existed south of the ice sheet at about the latitude of New Jersey through southern Iowa and northern Missouri. In the southern hemisphere, there is some evidence for former permafrost from this period in central Otago and Argentine Patagonia, but it was probably discontinuous except at the very highest latitudes.

Issue #178

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Beijing National Stadium

The Beijing National Stadium will be the main track and field stadium for the 2008 Summer Olympics and be host to the Opening and Closing ceremonies. The stadium will seat as many as 100,000 spectators during the Olympics, but this will be reduced to 80,000 after the games. It has replaced the original Guangdong Olympic Stadium. The stadium is 330 metres long by 220 metres wide, and is 69.2 metres tall. The 250,000 square metre (gross floor area) stadium is to be built with 36 km of unwrapped steel, with a combined weight of 45,000 tonnes. The stadium will cost up to 3.5 billion yuan (422,873,850 USD/ 325,395,593 EUR). The ground was broken in December 2003, and construction started in March 2004, but was halted by the high construction cost in August 2004.

Beijing National Stadium, the main stadium to the Olympics 2008 in Bejing, China.

In the new design, the roof of the stadium had been omitted from the design. Experts say that this will make the stadium safer, whilst reducing construction costs. The construction of the Olympic buildings will continue once again in the beginning of 2005.

In depth

The stadium's appearance is one of synergy, with no distinction made between the facade and the superstructure. The structural elements mutually support each other and converge into a grid-like formation - almost like a bird's nest with its interwoven twigs. The spatial effect of the stadium is novel and radical, yet simple and of an almost archaic immediacy, thus creating a unique historical landmark for the Olympics of 2008.

The stadium was conceived as a large collective vessel, which makes a distinctive and unmistakable impression both from a distance and when seen from up close. It meets all the functional and technical requirements of an Olympic National Stadium, but without communicating the insistent sameness of technocratic architecture dominated by large spans and digital screens.

Visitors walk through this formation and enter the spacious ambulatory that runs full circle around the stands. From there, one can survey the circulation of the entire area including the stairs that access the three tiers of the stands. Functioning like an arcade or a concourse, the lobby is a covered urban space with restaurants and stores that invite visitors to stroll around. Just as birds stuff the spaces between the woven twigs of their nests with a soft filler, the spaces in the structure of the stadium will be filled with inflated ETFE cushions. On the roof, the cushions will be mounted on the outside of the structure to make the roof completely weatherproof.

Whilst the rain is collected for rainwater recuperation, the sunlight filters through the translucent roof providing the lawn with essential ultraviolet radiation. On the facade, the inflated cushions will be mounted on the inside of the structure where necessary, e.g. to provide wind protection. Since all of the facilities - restaurants, suites, shops and restrooms - are all self-contained units, it is possible to do largely without a solid, enclosed facade. This allows natural ventilation of the stadium, which is the most important aspect of the stadium's sustainable design.

The sliding roof is an integral part of the stadium structure. When it is closed, it converts the stadium into a covered arena. Just as a tin is only complete with a lid, the roof, whether closed or open, is an elementary part of the whole. With its own structural logic, it is also a grid-like formation that forms a waterproof shell together with the inflated cushions.

Issue #179

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Sognefjord

The Sognefjord (Sognefjorden) is the second largest fjord in the world after Scoresby Sund on Greenland, and the largest in Norway. Situated in Sogn og Fjordane in Western Norway, its mouth is about 45 miles north of Bergen, and it stretches 203 km inland to the town of Skjolden.

An arm of the Sognefjord, Norway

The fjord reaches a maximum depth of 1,308 m below sea level. The greatest depths are found some way inland: near its mouth, the bottom rises abruptly to a sill about 100 m below sea level. The average width of the main branch of the Sognefjord is about three miles. Cliffs surrounding the fjord rise almost sheer from the water to heights of 1,000 m and more.

Boats connect settlements along the fjord and its sidearms. Towns on the fjord and its branches include Balestrand, Gudvangen and Flåm. Gudvangen is situated on Nærøyfjord, a branch of the Sognefjord particularly noted for its unspoilt nature and dramatic scenery, and only 300 m across at its narrowest point. From Flåm, the famous Flåmsbana railway climbs 900 m up to Myrdal in only 20 km - the steepest unassisted railway climb in the world.

Nærøyfjord

Over the Sognefjord a power line with a span of 4,597 m is installed. This is the second largest span of power lines in the world.

The fjord's beauty and the surpassing magnitude of its landscape has made it very popular among tourists, who power much of the local economy.

Issue #180

poon cho tang SG

Cumulonimbus

Cumulonimbus is a type of cloud that is tall, dense, and involved in thunderstorms and other bad weather. The clouds can form alone, in clusters, or along a cold front in a squall line.

Cumulonimbus cloud in central Oklahoma. The updraft is the large cloud mass at the center of the photo. The anvil is the flat layer at the top. The downdraft is the rainy area to the right.

Formation

To create a cumulonimbus cloud, you need three ingredients.

1. Plenty of moisture.
2. A mass of warm unstable air.
3. A source of energy to lift the warm, moist air mass rapidly upward.

Typically, the clouds form around front lines, near oceans where sea breezes provide the storm energy, or over mountains which push the air upwards.

When the warm air rises above the typically cooler air above it, it starts to cool and the water vapor condenses into water droplets. This adds more energy to the cloud, which soon becomes self-sustaining. As the air mass continues to rise, the water droplets continue to cool and form ice crystals. Gravity causes these droplets and crystals to start to fall, causing a downward movement to compete with the upward lift.

Instability between the updrafts and downdrafts causes static electrical charges to build up in the cumulonimbus cloud. The discharge of this electricity causes thunder and lightning.

During the spring and summer, cumulonimbus clouds are more likely to form in the afternoon, due to the heating of the earth's surface. However, they can also form along a cold front when the warm buoyant air is forced upward by the heavier cold air mass that cuts under the warmer air like a wedge. This can happen at any time of the year, as demonstrated by thunderstorms that happen in conjunction with snowstorms in the winter.

Appearance

The base of a cumulonimbus can be several miles across, and it can be tall enough to occupy middle as well as low altitudes: though formed at an altitude of about 3,000 to 4,000 metres (10,000 to 12,000 feet), its peak can reach up to 23,000 metres (75,000 feet) in extreme cases. Typically, it peaks at a much lower height. Cumulonimbus are also characterized by a flat, anvil-like top (the anvil dome), caused by straight line winds at the higher altitudes which shear off the top of the cloud. This anvil shape can precede the main cloud structure for many miles, causing anvil lightning.

Ideal anvil shaped cumulonimbus

Effects

Cumulonimbus storm cells can produce heavy rain (particularly of a convective nature) and flash flooding, as well as straight-line winds. Most storm cells die after about 20 minutes, when the precipitation causes more downdraft than updraft, causing the energy to dissipate. If there is enough solar energy in the atmosphere, however (on a hot summer's day, for example), the moisture from one storm cell can evaporate rapidly -- resulting in a new cell forming just a few miles from the former one. This can cause thunderstorms to last for several hours.

Cumulonimbus clouds contain severe convection currents, with very high, unpredictable winds, particularly in the vertical plane (updrafts and downdrafts). They are therefore extremely dangerous to aircraft. Smaller propeller-driven planes cannot cope with the conditions and must fly around them; larger jet aircraft fly over the smaller ones and around larger examples. Larger planes are also equipped with weather radar and wind shear detectors to help guide them through, in the event that they need to pass through such clouds to land.

The air convection can also form mesocyclones, which can cause hail and tornadoes.

Issue #181

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Emmons Glacier

Emmons Glacier is a glacier on the northeast flank of Mount Rainier, in Washington. It is the largest glacier (by area) in the continental United States, with a surface area of 4.3 square miles (11 km²).

Illustration of area around Emmons Glacier.

In the 1930s, the glacier was found to be receding quickly. However, in 1963, a rock fall from Little Tahoma Peak covered the lower glacier with rock debris. The debris cover insulates the ice from melting. As a result of decreased melting, the glacier advanced rapidly in the early 1980s. That advance continues today, but at a slower rate. Ice beneath the rock debris is melting irregularly and forming a vast hummocky area.

Emmons Glacier is often used as a route to climb to the peak of Mount Rainier.

Issue #182

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Charleston earthquake

The Charleston Earthquake of 1886 was the largest quake to hit the Southeastern United States.

It occurred at 9:50 PM on August 31, 1886. The earthquake killed between 60 and 100 people, and caused severe damage in Charleston, South Carolina. It damaged 2,000 buildings and caused $6 million worth of damage, while in the whole city the buildings were only valued at approximately $24 million.

Damage from Charleston earthquake of August 31, 1886

Major damage occurred as far away as Tybee Island, Georgia (over 60 miles away) and structural damage was reported several hundred miles from Charleston (including central Alabama, central Ohio, eastern Kentucky, southern Virginia, and western West Virginia). It was felt as far away as Boston and Chicago in the United States, Cuba and Bermuda outside of the US.

The earthquake is estimated to be between 6.6 to 7.3 on the Richter scale with an Modified Mercalli Intensity Scale of X. Sandblows were common throughtout the affected area due to liquefaction of the soil. More than 300 aftershocks of the 1886 earthquake occurred within thirty-five years. Minor earthquake activity that still continues in the area today may be a continuation of aftershocks. Very little to no historical earthquake activity occurred in the Charleston area prior to the 1886 event, which is unusual for any seismic area. This may have contributed to the severity of the tremor.

The 1886 earthquake is a heavily studied example of an intraplate earthquake. The earthquake is thought to have occurred on faults formed during Jurassic-aged rifting process during the break-up of Pangea. Similar faults are found along the east coast of North America.

Issue #183

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Snowy Mountains

The Snowy Mountains (the "Snowies") are the tallest Australian mountain range and contain Australia's tallest mountain, Mount Kosciuszko at 2,228 metres above sea level. They are part of the larger Great Dividing Range.

Image of the Snowy Mountains, Australia, generated from Worldwind.

Explored in 1835 and feeding the Snowy, Murrumbidgee and Murray rivers, the mountain range is host to a low laying type of pine tree suspected of being the world's oldest living organism. They are also thought to have had Aboriginal occupation for twenty thousand years; and are the one of the centres of the Australian snow industry during the winter months.

Yet the Snowy Mountains are perhaps best known for the Snowy Mountains Schemea project to dam the Snowy River, providing both water for irrigation and hydroelectricity.

The project began in 1949 employing a hundred thousand men, two-thirds of whom came from thirty other countries during the post-World War II years. Socially this project symbolises a period during which Australia became a "melting pot" of the twentieth century but which also changed Australia's character and increased its appreciation for a wide range of cultural diversity.

By 1974, 145 kilometres of underground tunnels and 80 kilometres of aqueducts connected the 16 dams, 7 power stations (2 underground), and one pumping station. The American Society of Civil Engineers rated the Snowy Scheme as "a world-class civil engineering project".

Issue #184

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Freezing rain

Freezing rain begins as snow falling from a cloud towards earth. It melts completely on its way down in a layer of warm (above freezing) air and then supercools in a small layer of cold air just before it impacts the surface. Due to it being supercooled the water freezes again upon impact.

A shrub coated by glaze after a night of freezing rain.

Ice storms often cause major power outages. The ice will accumulate to thicknesses of several inches. Power lines coated with ice become extremely heavy, causing support poles, insulators and lines to break. Tree limbs, with branches heavily coated in ice also can break off under the enormous weight and fall onto power lines. The ice that forms on roadways makes vehicle travel nearly impossible. Unlike snow, wet ice provides almost no traction. Vehicles will slide on even gentle slopes. One particularly severe ice storm struck eastern Canada in 1998.

Issue #185

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Banff National Park

Banff National Park is located in the Canadian Rockies west of the City of Calgary, and includes the town of Banff, Alberta. Banff was Canada's first national park. Attractions include mineral hot springs, mountain scenery, camping, climbing, hiking, golfing, horse-back riding, alpine and nordic skiing, the Banff Springs Hotel, and Lake Louise. The park was created when the Rocky Mountains Park Act became law in Canada on 23 June 1887.

Banff National Park

Banff National Park covers 6,641 square kilometres (2,564 square miles) and contains over 1,600 kilometres (1,000 miles) of trails.

Banff took its name from the Canadian Pacific Railway station, which is believed to be named after the town in Aberdeenshire, Scotland. Prior to local government reorganisation, the Scottish Banff was in the former county of Banffshire.

Castle Mountain in Banff

A park pass is required for stopping in the park and permit checks are common during the summer months, especially at Lake Louise and the start of the Icefields Parkway. A permit is not required if travelling straight through the park without stopping. The Trans-Canada Highway goes through the park. The death of wildlife on the highway from vehicles is a problem, which has resulted in the highway being fenced off and the construction of wildlife under- and over-passes.

Banff wildlife overpass

Some of the park's many photogenic vistas are Lake Minnewanka, Mount Rundle, the Vermilion Lakes, Moraine Lake in the Valley of the Ten Peaks (renowned for its turquoise blue waters), Bow Lake, and Peyto Lake.

Issue #186

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Strabo

"Strabo" ("squinty") was a term employed by the Romans for anyone whose eyes were distorted or deformed. The father of Pompey was called "Pompeius Strabo." A native of Sicily so clear sighted that he could see things at great distance as if they were nearby was also called "Strabo."

The most significant figure by this name, however, was Strabo (born 63 BC or 64 BC, died ca. 24 AD), a Greek historian, geographer and philosopher. Nowadays, Strabo is mostly famous for his Geographika ("Geography"), a 17-book work containing history and descriptions of people and places all over the world as known to him.

Strabo, in a 16th century engraving.

Strabo was born in a wealthy family from Amaseia (current-day Amasya, Turkey) in Pontus, which became part of the Roman empire just around the time of his birth. He studied under various geographers and philosophers, first in his own area, later in Rome. He was philosophically a stoicist, politically a proponent of Roman imperialism. Later he made extensive travels to among others Egypt and Ethiopia. It is not known when he wrote his Geographika though remarks in it place the finished version in the reign of Emperor Tiberius; some place its first drafts around 7 AD, others around 18 AD. The death of Juba, king of Maurousia is mentioned, an event which took place in 23 AD.

Strabo's Historia is lost: Strabo quotes it himself, and other classical authors mention that it existed. All that we have of it is a fragment of papyrus now at the University of Milan (renumbered P[apyrus] 46).

Several different dates have been proposed for Strabo's death, most of them placing it shortly after 23 AD.

The Geography

The Geographika is an extensive work in Greek, spanning 17 volumes, and can be regarded as an encyclopedia of the geographical knowledge of his time; except for parts of Book 7, it has come down to us complete. Yet while it does cover the entire world known to the Greeks and Romans of his time, it suffers from several major flaws: a constant and very intrusive defense of the poet Homer as a geographical source, leading him to dismiss more recent writers, such as Herodotus, who were often eyewitnesses to what they reported; a preoccupation with minute, often captiously argumentative, criticism of these other writers; a peculiarly Greek aprioristic attitude to facts, seeking to derive them from the pure exercise of reason: in sum, one would prefer more geography and less argumentation. These byways, however, do provide modern scholars with valuable historical information on the methods of ancient geography and on many older geographers whose works have not come down to us.

Some thirty manuscripts of Geographika or parts of it have survived, almost all of them medieval copies of copies, though there are fragments from papyrus rolls which were probably copied out ca AD 100-300. Scholars have struggled for a century and a half to produce an accurate edition close to what Strabo wrote. A definitive one has been in publication since 2002, appearing at a rate of about a volume a year.

Issue #187

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Altun Ha

Altun Ha is the name given to ruins of an ancient Maya city in Belize, located in the Belize District about 30 miles (50 km) north of Belize City and about 6 miles (10 km) west of the shore of the Caribbean Sea.

A portion of the ruins of Altun Ha, Belize, with the Temple of the Masonry Altars visible in the background across a plaza.

"Altun Ha" is a modern name in the Maya language, coined by translating the name of the nearby village of Rockstone Pond. The ancient name is at present unknown.

The largest of Altun Ha's temple-pyramids, the "Temple of the Masonry Altars", is 54 feet (16 m) high. A drawing of this structure is the logo of Belize's leading brand of beer, "Belikin".

The site covers an area of about 5 miles (8 km) square. The central square mile of the site has remains of some 500 structures.

Archeological investigations show that Altun Ha was occupied by 200 BC. The bulk of construction was from the Maya Classic era, c. 200 to 900 AD, when the site may have had a population of about 10,000 people. About 900 there was some looting of elite tombs of the site, which some think is suggestive of a revolt against the site's rulers. The site remained populated for about another century after that, but with no new major ceremonial or elite architecture built during that time. After this the population dwindled, with a moderate surge of reoccupation in the 12th century before declining again to a small agricultural village.

The ruins of the ancient structures had their stones reused for residential construction of the agricultural village of Rockstone Pond in modern times, but the ancient site did not come to the attention of archeologists until 1963, when the existence of a sizable ancient site was recognized from the air by pilot and amateur Mayanist Hal Ball.

Ruins of Altun Ha, Belize, showing architectural grotesque masks, detail on temple pyramid.

Starting in 1965 an archeological team lead by Dr. David Pendergast of the Royal Ontario Museum began extensive excavations and restorations of the site, which continued through 1970. One of the most spectacular discoveries is a large (almost 10 pounds or 5 kilograms) piece of jade elaborately carved into an image of the head of the Maya Sun God, Kinich Ahau. This jade head is considered one of the national treasures of Belize.

A road connects Altun Ha to Belize's Northern Highway, and the site is accessible for tourism.

Issue #188

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Sluice

A sluice is a water channel that is controlled at its head by a gate. A sluice gate is traditionally a wooden or metal plate which slides in grooves in the sides of the channel. Sluice gates are commonly used to control water levels and flow rates in rivers and canals.

Sluice gates on the River Thames

Operation

Raising a sluice gate allows water to flow under it. (The term sluice gate refers to any gate that operates by allowing water to flow under it.) When a sluice gate is fully lowered, water sometimes spills over the top, in which case the gate operates as a weir.

Usually a mechanism drives the sluice gate up or down. This may be a simple, hand-operated, worm drive or rack and pinion drive, or it may be electrically or hydraulically powered.

The gates of a lock may work in a way similar to the way a sluice gate works, but traditional canal lock gates are hinged to swing like double doors.

Flow calculation

The sluice flow rate formula is:

where:

Q is the flow
A is the area of the sluice
g is the acceleration due to gravity on the Earth's surface (approx. 9.81 m/s²)
h is the head across sluice
C is the discharge coefficient (typically 0.61 for small depth ratios)

Types of sluice gates

- Flap sluice gate - a fully automatic type, which is controlled by the pressure head across it. It is a gate hinged at the top. When pressure is from one side, the gate is kept closed. A pressure from the other side opens the sluice when a threshold pressure is surpassed.

- Vertical rising sluice gate - a plate sliding in the vertical direction, controlled by machinery.

- Radial sluice gate - a structure, where a small part of a cylindrical surface serves as the gate, supported by radial constructions going through the cylinder's radius, continuing through to a counterweight.

- Rising sector sluice gate - also a part of a cylindrical surface, which rests at the bottom of the chanel and rises by rotating around its centre.

- Needle sluice - a sluice formed by a number of thin needles held against a solid frame through water pressure as in a needle dam.

Issue #189

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