Quicksand

Quicksand is a colloid hydrogel consisting of fine granular matter (such as sand or silt), clay, and salt water. In the name, as in that of quicksilver (mercury), "quick" does not mean "fast," but "living" (cf. the expression the quick and the dead).

Quicksand may be found inland (on riverbanks, near lakes, or in marshes), or near the coast.

One region notorious for its quicksands is Morecambe Bay, England. As the bay is very broad and shallow, a person trapped by the quicksand would be exposed to the danger of the returning tide, which can come in rapidly.

Flash flood

A flash flood is a rapid flooding of geomorphic low-lying areas - washes, rivers and streams. It is caused by heavy rain associated with a thunderstorm, hurricane, or tropical storm. Flash floods can also occur after the collapse of an ice dam, or a human structure, such as a dam, for example, the Johnstown Flood of 1889. Flash floods are distinguished from a regular flood by a timescale less than six hours.

Tropopause

The tropopause is the atmospheric boundary between the troposphere and the stratosphere. Going upward from the surface, it is the point where air ceases to cool with height, and becomes almost completely dry. More formally, it is the region of the atmosphere where the lapse rate changes from positive (in the troposphere) to negative (in the stratosphere). This occurs at the equilibrium level (EL), a value important in atmospheric thermodynamics. The exact definition used by the World Meteorological Organization is:

the lowest level at which the lapse rate decreases to 2 °C/km or less, provided that the average lapse rate between this level and all higher levels within 2 km does not exceed 2 °C/km.

Auroras

Auroras, sometimes called the northern and southern (polar) lights or aurorae (singular: aurora), are natural light displays in the sky, usually observed at night, particularly in the polar regions. They typically occur in the ionosphere. They are also referred to as polar auroras. In northern latitudes, the effect is known as the aurora borealis, named after the Roman goddess of dawn, Aurora, and the Greek name for north wind, Boreas, by Pierre Gassendi in 1621.^[1] The aurora borealis is also called the northern polar lights, as it is only visible in the sky from the Northern Hemisphere, the chance of visibility increasing with proximity to the North Magnetic Pole, which is currently in the arctic islands of northern Canada. Auroras seen near the magnetic pole may be high overhead, but from further away, they illuminate the northern horizon as a greenish glow or sometimes a faint red, as if the sun were rising from an unusual direction. The aurora borealis most often occurs near the equinoxes; from September to October and from March to April. The northern lights have had a number of names throughout history. The Cree people call this phenomenon the "Dance of the Spirits." In the middle age the auroras has been called by sign of God (see Wilfried Schröder, Das Phänomen des Polarlichts, Darmstadt 1984). Auroras can be spotted throughout the world. It is most visible closer to the poles due to the longer periods of darkness and the magnetic field.

Its southern counterpart, the aurora australis or the southern polar lights, has similar properties, but is only visible from high southern latitudes in Antarctica, South America, orAustralasia. Australis is the Latin word for "of the South."

Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates. The word derives from the Neolatin noun epicentrum^[1] from the Greek adjective ἐπίκεντρος (epikentros) "central", from ἐπί (epi) "on, upon, at" and κέντρον(kentron) "centre".

In the case of earthquakes, the epicenter is directly above the point where the fault begins to rupture, and in most cases, it is the area of greatest damage. However, in larger events, the length of the fault rupture is much longer, and damage can be spread across the rupture zone. For example, in the magnitude 7.9, 2002 Denali earthquake in Alaska, the epicenter was at the western end of the rupture, but the greatest damage occurred about 330 km away at the eastern end of the rupture zone

Altai Mountains

The Altai Mountains (Russian: Алтай, Altay; Mongolian: Алтай; Chinese: 阿尔泰山脉,) are a mountain range in central Asia, where Russia, China, Mongolia and Kazakhstan come together, and where the rivers Irtysh and Ob have their sources. The Altai Mountains are known as the Turkic peoples' birthplace. The northwest end of the range is at 52° N and between 84° and 90° E (where it merges with the Sayan Mountains to the east), and extends southeast from there to about 45°N 99°ECoordinates: 45°N 99°E, where it gradually becomes lower and merges into the high plateau of the Gobi Desert.

Tropical cyclone From Wikipedia, the free encyclopedia

A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones feed on heat released when moist air rises, resulting in condensation of water vapor contained in the moist air. They are fueled by a different heat mechanism than other cyclonic windstorms such as nor'easters, European windstorms, and polar lows, leading to their classification as "warm core" storm systems. Tropical cyclones originate in the doldrums near the equator, about 10° away from it

Tropical Cyclone Programme

Tropical Cyclone Programme

There are six such meteorological centres and five regional Tropical Cyclone Warning Centres utilized for naming of tropical cyclones and the distribution of tropical cycloneadvisories and warnings:

• Southwest Pacific Ocean: RSMC Nadi-Tropical Cyclone Centre - Fiji Meteorological Service (Nadi, Fiji)
• Southwest Indian Ocean: RSMC La Reunion-Tropical Cyclone Centre / Météo France (Réunion island, French Overseas Department)
• Bay of Bengal and Arabian Sea: RSMC - Tropical Cyclones New Delhi / India Meteorological Department (New Delhi, India)
• Western North Pacific Ocean and South China Sea - RSMC Tokyo / Japan Meteorological Agency (Tokyo, Japan)
• Central North Pacific Ocean - RSMC Honolulu Central Pacific Hurricane Center (Honolulu, Hawaii, USA)
• Northeast Pacific Ocean, Gulf of Mexico, Caribbean Sea, and north Atlantic Ocean - RSMC Miami / National Hurricane Center^[1]

Alpide belt

The Alpide belt is a mountain range which extends along the southern margin of Eurasia. Stretching from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic, it includes the Alps, the Carpathians, the mountains of Asia Minor and Iran, the Hindu Kush, the Himalayas, and the mountains of Southeast Asia. It is the second most seismic region (5-6% of earthquakes and 17% of the world's largest earthquakes) in the world. The Pacific Ring of Fire is the most seismic region.

Ring of Fire

Pacific Ring of Fire

From Wikipedia, the free encyclopedia

The Pacific Ring of Fire

The Pacific Ring of Fire (or sometimes just the Ring of fire) is an area where large numbers of earthquakes and volcanic eruptions occur in the basin of thePacific Ocean. In a 40,000 km horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. The Ring of Fire has 452 volcanoes and is home to over 75% of the world's active and dormant volcanoes. It is sometimes called the circum-Pacific belt or the circum-Pacific seismic belt.

India--- International Programmes

International Programmes

Law of the Sea

The Department of Ocean Development is the nodal agency for implementation of the provisions of United Nations Convention of the Law of the Sea (External website that opens in a new window)(UNCLOS), in India. UNCLOS is an important instrument, which establishes the framework and mechanisms for management of oceans. India ratified the Convention in June 1995. With coming into force of United Nations Convention on Law of the Sea, the institutions such as International Seabed Authority (ISBA) and Commission on the Limits of Continental Shelf (CLCS) came into existence. India has been re-elected in the Commission on the Limits of Continental Shelf for the second term for a period of 5 years in the year 2002. India is elected on all the institutions established under United Nations Convention on Law of the Sea. viz. International Seabed Authority(External website that opens in a new window), Commission on Limits of Continental Shelf and International Tribunal on Law of the Sea. India regularly participates in the meetings of ISBA, CLCS and also in the meeting of States Parties on Law of the Sea (SPLOS) and continues to play the key role in decision making in matters on Law of the Sea.

Delineation of Outer Limits of Continental Shelf

According to the provisions of United Nations Convention on Law of the Sea (UNCLOS), the coastal State that intends to delineate the outer limits of the continental shelf beyond 200 nautical miles is required to submit particulars of such limits along with the supporting scientific and technical data. The UNCLOS came into force in November 1994 and India ratified it in June 1995. If delineation is properly undertaken, India would be in a position to gain substantial area beyond the EEZ. It is required to be submitted by May 2009 and would be examined by the Commission on the Limits of Continental Shelf(External website that opens in a new window)(CLCS). The National Centre for Antarctic and Ocean Research (NCAOR) at Goa, an autonomous body under the DOD, is coordinating this national endeavour with active co-operation and participation of all national institutions.

Inter-governmental Oceanographic Commission

Established in 1960 under UNESCO, the Inter-governmental Oceanographic Commission(External website that opens in a new window) (IOC) is promoting global co-operation in marine scientific investigations, ocean services and capacity building in developing countries through the concerted efforts of all the 127 member states. India through its continued participation in IOGOOS, is contributing to the growth of oceanographic research and services.

COMNAP/SCALOP/ATCM Meetings

After becoming a member of the Antarctic Treaty, India continues to participate in the meeting of the Council of Managers of National Antarctic Programme(External website that opens in a new window) (COMNAP) and Standing Committee of Antarctic and Logistic Operations (SCALOP), Antarctic Treaty Consultative Meeting (ATCM) and Commission for the Conservation of Antarctic Marine Living Resources (External website that opens in a new window)(CCAMLR).

Bilateral Programmes

India signed bilateral agreements with several countries including Russia, China, Portugal and Mauritius in last 5 years and has successfully implemented collaborative programmes in Myanmar, Mauritius, and Seychelles in the field of Ocean Science and Technology. India organised 5 days training programme for Sri Lanka and Myanmar on Delineation of Outer Limits of Continental Shelf at NCAOR, Goa.

Source: National Portal Content Management Team

Horse latitudes

Horse latitudes or Subtropical High are subtropic latitudes between 30 and 35 degrees both north and south. This region, under a ridge of high pressure called the subtropical high, is an area which receives little precipitation and has variable winds mixed with calm.

The term horse latitudes supposedly originates from when Spanish sailing vessels transported horses to the West Indies. Ships would often become becalmed in mid-ocean in this latitude, thus severely prolonging the voyage; the resulting water shortages would make it necessary for crews to throw their horses overboard.

The term might be derived from the "dead horse" ritual, a practice in which the seaman would parade a straw-stuffed effigy of a horse around the deck before throwing it overboard. Seamen were often paid partly in advance before a long voyage (see Beating a dead horse), and the "dead horse" was this period of time (usually a month or two). The ceremony was to celebrate having worked off the "dead horse" debt. As European west bound shipping would reach the subtropics at about the time the "dead horse" was worked off, the region became associated with the ceremony.^[1]

The consistently warm, dry conditions of the horse latitudes also contribute to the existence of temperate deserts, such as the Sahara Desert in Africa, the southwestern United States and northern Mexico, and parts of the Middle East in the Northern Hemisphere, and the Atacama Desert, the Kalahari Desert, and the Australian Desert in the Southern Hemisphere.

Mercator projection

From Wikipedia, the free encyclopedia

World map in the Mercator projection

The Mercator projection is a cylindrical map projection presented by the Flemish geographer and cartographer Gerardus Mercator, in 1569. It became the standard map projection for nautical purposes because of its ability to represent lines of constant course, known as rhumb lines or loxodromes, as straight segments. While the linear scale is constant in all directions around any point, thus preserving the angles and the shapes of small objects (which makes the projection conformal), the Mercator projection distorts the size and shape of large objects, as the scale increases from the Equator to the poles, where it becomes infinite.

Eye (cyclone)

From Wikipedia, the free encyclopedia

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The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is a roughly circular area and typically 30–65 km (20–40 miles) indiameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather of a cyclone occurs. The cyclone's lowest barometric pressure occurs in the eye, and can be as much as 15% lower than the atmospheric pressure outside the storm.^[1]

In strong tropical cyclones, the eye is characterized by light winds and clear skies, surrounded on all sides by a towering, symmetric eyewall. In weaker tropical cyclones, the eye is less well-defined, and can be covered by the central dense overcast, which is an area of high, thick clouds which show up brightly on satellite imagery. Weaker or disorganized storms may also feature an eyewall which does not completely encircle the eye, or have an eye which features heavy rain. In all storms, however, the eye is the location of the storm's minimum barometric pressure: the area where the atmospheric pressure at sea level is the lowest