Jet Stream

What is the Jet Stream?

The jet stream is a river of wind that blows horizontally through the upper layers of the troposphere, generally from west to east, at an altitude of 20,000 - 50,000 feet (6,100 - 9,144 meters), or about 7 miles (11 kilometers) up. 

A jet stream develops where air masses of differing temperatures meet. For this reason, surface temperatures determine where the jet stream will form. The greater the difference in temperature, the faster the wind velocity inside the jet stream. Jet streams can flow up to 200 mph (322 km/h), are 1000's of miles long, 100's of miles wide, and a few miles thick.

Where the jet stream begins

o    Air warmed in the tropics around the equator fuels the jet stream as it rises. Hitting the tropopause at about 58,000 feet (the layer of the atmosphere separating the troposphere from the stratosphere), it is drawn toward the colder air at the north and south poles.

Jet Stream Atmospheric Positions   Positions of jet streams in the atmosphere. Arrows indicate directions of mean motions in a meridional plane.

How it forms a convection cell

o       At higher latitudes, the warm air cools and sinks, drawing more warm air in behind it. The cooled air flows back towards the equator, creating a loop or convection cell.

Why the jet stream flows on an easterly course

o     

As the earth rotates on its axis, so does the air around it. Due to this easterly rotation, rising warm air builds up momentum going the same direction. Thus, the jet stream cannot flow due north or due south, but makes an angular approach from the west, toward both poles.

Why the jet stream is so fast

o   Objects and air at the equator rotate around the earth's axis much faster than they do at more northerly or southerly latitudes. Thus, as the warmer air is drawn toward the poles, it moves faster, relative to the earth's surface. Because the rising warm air feeding the jet stream happens all along the equator, the effects accumulate, giving rise to high-speed winds.

The size of the jet stream

o    The jet stream is no more than three miles thick, a few hundred miles wide and circles the earth. The size changes as temperature and other air masses meet the jet stream, causing it to shift its course.

Identification

o    Jet streams move around the Earth in a narrow band. They are created by the difference in temperatures between two air masses, usually cold polar air and warm tropical air. The temperature variance creates gradients in air pressure, which in turn affects the strength of the winds in the jet stream. The greater the variance, the greater the wind speed. Jet stream winds normally are 100 to 200 mph but can reach speeds as high as 300 mph.

Development

o    A jet stream develops where air masses of differing temperatures meet, so surface temperatures help determine where they will form. The jet stream is snakelike, undulating like a river, because of the pressures on either side from the warm and cold air masses.

When the jet stream is pushed south by a cold air mass, it allows high pressure to sink and create colder-than-normal weather in the South. In the opposite situation, when northern regions get warmer than normal, the jet stream has been pushed north by tropical air.

Jet streams travel from west to east in both hemispheres.

History

o    Jet streams were discovered in the 1920s by meteorologist Wasburo Ooishi, who was using weather balloons for his study of high elevation wind patterns over Japan. In 1939, German meteorologist H. Seilkopf was the first to use the term "jet stream" in a published scientific paper.

However, it wasn't until World War II, when the Japanese used the jet stream for fire balloon attacks on the American mainland, that the upper-level winds gained public recognition. Wiley Post, an American aviation pioneer, is credited with being the first person to fly within a jet stream. He and other WWII military pilots flying Boeing B-29 Superfortress bombers found the jet stream made high altitude flights difficult.

Weather Effects

o    Currents travel at varying wind speeds within a jet stream, with the greatest speeds at the core. A jet stream contains jet streaks, where the wind velocity is higher than the rest of the stream. The jet streaks cause air to rise, lowering the air pressure at the Earth's surface. When surface pressures are low, the rising air can form clouds, precipitation and storms.

Air Travel

o    Jet streams play a major role in air travel. Eastbound flights usually take less flying time than westbound flights because of help from the fast-moving air. Jet streams can contain wind shear, a violent and sudden change in wind direction and speed, which is a major threat in air travel. Wind shear has caused airliners to suddenly lose altitude, putting them in danger of crashing. In 1988, the FAA decided that all commercial aircraft must have wind-shear warning systems, but it wasn't until 1996 that all airlines had them on-board.

Types of Jet Streams !!!   SUBTROPICAL JET STREAMS.— These jets, like the polar-front jets, are best developed in winter and early spring. During summer, in the Northern Hemisphere, the subtropical jet weakens considerably, and it is only identifiable in sporadic velocity streaks around the globe. During winter, subtropical jets intensify and can be found between 20° and 50° latitude. Their maximum speed approaches 300 knots, although these higher wind speeds are associated with their merger with polar-front jets. The core is most frequently found between 35,000 and 40,000 feet. A subsidence motion accompanies subtropical jets and gives rise to predominantly fair weather in areas they pass over. These jets are also remarkably persistent from time to time, but they do fluctuate daily. Sometimes they drift northward and merge with a polar-front jet. Over Asia in summer, the subtropical jet is replaced by the tropical easterly jet stream. TROPICAL EASTERLY JET STREAM.— This jet occurs near the tropopause over Southeast Asia, India, and Africa during summer. The strongest winds are over southern India, but they are not as intense as the winds encountered in polar-front or subtropical jet streams. This jet is closely connected to the Indian and African sum-mer monsoons. The existence of this jet implies that there is a deep layer of warm air to the north of the jet and colder air to the south over the In-dian Ocean. This warm air is of course associ-ated with the maximum heating taking place over India in summer, while the colder air is over the ocean. The difference in heating and cooling and the ensuing pressure gradient is what drives this jet. POLAR-NIGHT JET STREAM.— This jet meanders through the upper stratosphere over the poles. It occurs only during the long winter night. Remember, night is 6 months long over the pole in which winter is occurring. The polar stratosphere undergoes appreciable cooling due to the lack of solar radiation. The horizontal temperature gradient is strongly established bet-ween the equator and the pole, and the pressure gradient creates this westerly jet. The temperature gradient breaks down intermittently during middle and late winter in the Northern Hemisphere; therefore, the jet is intermittent at these times. In the Southern Hemisphere the temperature gradient and jet disappear rather abruptly near the time of the spring equinox.

Detailed explanation on how the Jet Streams affect the Monsoons and the Indian Sub Continent ? Jet Streams are fast flowing winds blowing in a narrow zone in the high altitude above 12000 m in troposphere. There are a number of separate jet streams whose speed varies from 110 km/h in summer to about 184 km/h in winter. In winter the sub-tropical westerly jet streams bring rain to the western part of India, especially Himachal Pradesh, Haryana and Punjab. In summer the sub-tropical easterly jet blows over Peninsular India approximately at 14ON and bring some rain and storm. There are different jet streams and in respect of the climate and monsoons of India it is the Subtropical Jet Stream (STJ) and the countering easterly jet that are most important. As the summertime approaches there is increased solar heating of the Indian subcontinent, this has a tendency to form a cyclonic monsoon cell situated between the Indian Ocean and southern Asia. This cell is blocked by the STJ which tends to blow to the south of the Himalayas, as long as the STJ is in this position the development of summer monsoons is inhibited. During the summer months the STJ deflects northwards and crosses over the Himalayan Range. The altitude of the mountains initially disrupts the jet but once it has cleared the summits it is able to reform over central Asia. With the STJ out of the way the subcontinental monsoon cell develops very quickly indeed, often in a matter of a few days. Warmth and moisture are fed into the cell by a lower level tropical jet stream which brings with it air masses laden with moisture from the Indian Ocean. As these air masses are forced upward by north India’s mountainous terrain the air is cooled and compressed, it easily reaches it’s saturation vapour point and the excess moisture is dissipated out in the form of monsoon rains. The end of the monsoon season is brought about when the atmosphere over the Tibetan Plateau begins to cool, this enables the STJ to transition back across the Himalayas. This leads to the formation of a cyclonic winter monsoon cell typified by sinking air masses over India and relatively moisture free winds that blow seaward. This gives rise to relatively settled and dry weather over India during the winter months. This year has been something of an exception. Atmospheric changes over the southern Pacific Ocean led to warmer than usual waters flowing into the Indian Ocean. This provided additional moisture to feed the monsoon systems. Further to the north the polar jet stream stalled due to being countered by Rossby Waves, there was a large kink in the stream and this was centred over Russia. The stalled system prevented weather systems being drawn across Russia and the kink acted as a barrier trapping hot air to the south and cold air to the north. The consequence of this static mass of hot air was the heatwave that devastated Russia. With the jet stream stalled the STJ was unable to transit across the Himalayas as it would do ordinarily, the monsoon cell to the south, fed by warmer waters in the Indian Ocean, had nowhere to go and as a consequence it deposited vast amounts of rain over Pakistan, Himalchal Pradesh amd Jammu and Kashmir and this led to extensive flooding. The Somali Jet The monsoon wind that is deflected to the north as it crosses the equator is further deflected to the east by the mountains of Africa. The progress of the southwest monsoon towards India is greatly aided by the onset of certain jet streams including the crucial Somali jet that transits Kenya, Somalia and Sahel and exits the African coast at 9 degrees north at low level and very fast. J. Findlater, a British meteorologist observed this low level jet stream was found to be most pronounced between 1.0 and 1.5 km above the ground. It was observed to flow from Mauritius and the northern part of the island of Madagascar before reaching the coast of Kenya at about 3º S. Subsequently it ran over the plains of Kenya, Ethiopia and Somalia before reaching the coast again around 9º N. The jet stream appears to be fed by a stream of air, which moves northwards from the Mozambique Channel. The major part of this low level jet penetrates into East Africa during May and, subsequently, traverses the northern parts of the Arabian Sea before reaching India in June. Observations suggest that the strongest cross equatorial flow from the southern to the northern hemisphere during the Asian Summer Monsoon is in the region of the low level jet. This has intrigued meteorologists, because it is not clear why the major flow of air from the southern to northern hemisphere should take place along a narrow preferred zone off the East African coast. The importance of the low level jet arises from the fact that its path around 9º N coincides with a zone of coastal upwelling. As the strong winds drive away the surface coastal waters towards the east, extremely cold water from the depths of the sea rise upwards to preserve the continuity of mass. This upwelling is brought about by strong low level winds. After the low level jet moves towards the Indian coastline around 9º N, it separates into two branches. One appears to move to the northern parts of the Indian Peninsula while the other recurves towards the southern half of the Indian coastline and Sri Lanka. It is still not clear why the jet separates into two branches. Findlater analysed the wind profile for the months of July and August and found a relationship between the cross-equatorial airflow, between 1.0 and 1.5 km, over Kenya and the rainfall over western India. He opined that an increase in the cross-equatorial flow was followed by an increase in rainfall over the west coast.  The Somali Current Oceanographers have been interested in yet another phenomenon, which appears to have some relationship with the low level jet stream off the coast of eastern Africa. This ocean current named the Somali Current, flows northward from the equator to 9º N, where it separates from the coast. It is a fairly strong current with a velocity maximum of 2 m m/s, but speeds as large as 3 m m/s have also been observed. The Somali Current may be considered to be a western boundary current of the Indian Ocean. But, its peculiar feature is a reversal in direction with the onset of the summer monsoon. In winter, this current is from north to the south running southwards from the coast of Arabia to the east African coastline; but with the advent of the summer monsoon it reverses its direction and flows from the south to the north. This suggests a relationship with the reversal of monsoon winds, but usually the oceans respond very slowly to changes in atmospheric circulation and oceanographers have wondered why the Somali Current reverses its direction and reaches its maximum speed nearly a month earlier than the onset of southwesterly monsoon winds. Sub-tropical Westerly and Tropical Jet Streams Certain interesting changes take place in the upper atmosphere with the advent of the summer monsoon. Towards the end of May, a narrow stream of air, which moves from the west to the east over northern India, suddenly weakens and moves to a new location far to the north of the Himalayas. This is known as sub-tropical westerly jet stream. Its movement towards the north is one of the main features associated with the onset of the monsoon over India. As the westerly jet moves north, yet another jet stream sets in over the southern half of the Indian peninsula. This flows in the reverse direction from the east to west. It is called tropical easterly jet, and it exhibits periodic movements to the north and south of its mean location during the hundred-day monsoon season beginning with the first of June and ending around mid-September. The altitude at which the winds attain their maximum strength in the tropical easterly jet is around 150 hPa, but the maximum winds associated with the sub-tropical westerly jet occur at a lower altitude of 300 hPa. A remarkable feature of the tropical easterly jet is that it can be traced in the upper troposphere right up to the west coast of Africa. HPa refers to 'hecta Pascal' and is a unit of measure of atmospheric air pressure

The total ABCD of Wheat !!!

What Is Durum Wheat?

Durum wheat is a type of wheat that is high in protein, gluten, and generally very firm and strong. Kernels of durum wheat are usually large and amber colored. This wheat is most commonly used for making pasta rather than for baking because of its denseness and cooking quality. Pasta made from durum wheat is typically yellow in color because of the wheat's yellow endosperm. The endosperm of wheat is found in the kernel and is usually full of niacin, iron, starch, and protein.

What Are the Benefits of Wheat Germ?

The benefits of wheat germ are numerous, one of them being that this high fiber, high protein part of wheat is one the tastier health foods. It can easily be incorporated into lots of recipes or added to things like cereals or smoothies to include extra nutrition. Unless people are intolerant to wheat, most will find this portion of the wheat kernel easy to digest, though it may be a good idea to start slow in adding it to foods because of its relatively high fiber content. 

What Are Wheat Berries?

 Wheat berries are whole wheat kernels which have had their husks removed. Like other whole grains, they provide a great deal of valuable nutrition including vitamins, minerals, and fiber, and they are often touted as a good inclusion in a healthy diet. Health food stores and some supermarkets carry wheat berries in a variety of packagings, and sometimes finished food products made with wheat berries such as mixed grain salads are also available at markets.

What is a Wheat Allergy?

A wheat allergy is a type of food allergy characterized by adverse reactions to the consumption of wheat. In addition to causing problems when wheat is eaten, wheat allergies may also result in skin reactions in response to contact with wheat, and in respiratory problems after inhaling wheat pollen and wheat dust. Along with soy, dairy, egg, shellfish, tree nut, peanut, and fish allergies, wheat allergies are very widespread around the world, with people from a wide variety of backgrounds experiencing wheat allergies and sensitivity to wheat.

What is the Difference Between Whole Grain and Whole Wheat? 

When it comes to the differences between whole grain products and whole wheat products, there may be some confusion among consumers. While there are many similarities between whole grain products and whole wheat products, there are a few differences that could be very important. Here are some examples.
One of the main differences between whole wheat and whole grain is the process that is used to prepare the grain flour. With whole-wheat flour, the grain has gone through a refining process that has removed some of the nutritional value from the end product. By contrast, whole-grain flour does not go through this refining process, and thus maintains the natural level of nutrients. 

What is Gluten Flour?

There are several types of gluten flour, most derived from wheat. Gluten is a protein found abundantly in the endosperm of wheat that adds stickiness and sponginess to dough. When people cook with other whole grains, they may not have adequate gluten, and might need to use a bit of pure gluten in order to make breads and other baked goods lighter. There are a few ways to add extra gluten to dough, most of them employing some type of gluten flour to accomplish this. 

What is Kamut® Grain?

Kamut® grain is an ancient grain, and a close relative to durum wheat. It is growing in popularity as an alternative to traditional wheat sources because it is considered nutritionally superior to many other forms of wheat. Research suggests that Kamut® grain may first have been grown in either Egypt or Asia.
When it was first grown in the US, it had no trademark, and was grown mainly as a novelty grain by one farmer in Montana, who got samples of the grain from his son, a WWII airman. The wheat was dubbed King Tut’s grain because of the suggestion of its ancient uses and possible origins. It wasn’t until the 1970s that any farmers thought to grow the wheat in a commercial manner, and there was only one remaining sample of the Montana farmer’s harvest, grown in the 1940s, with which to work. 

The anatomy of a grain of wheat

A whole grain is mostly made up of 3 parts. The bran, the germ, and the endosperm. Check out this cool picture.
As you can see from the picture. The endosperm makes up most of the kernal, the bran comes next and the germ makes up the least amount. Manufacturers remove the bran and germ when they make refined bread flour (white flour). Which is not good at all.

The bran is the outside layer of the grain and it is a rich source of many vitamins and minerals like magnesium, riboflavin, thiamin, phosphorus, niacin, iron and zinc. Almost all of the fiber within the grain comes from the bran.

The germ is the part of the grain from which a new plant would sprout if you were to plant it. It is a concentrated source of vitamin E, magnesium, riboflavin, thiamin, phosphorus, niacin, iron and zinc. The germ also contains some fat and protein.

The endosperm has very small amounts of vitamins, not nearly close to what the bran and germ have.

Buckwheat - is it wheat or what?

Don’t let the word ‘wheat’ in it’s name confuse you. Buckwheat (Fagopyrum esculentum) looks like a grain and tastes like a grain but isn't a grain at all. Buckwheat is thought of as a cereal, but is actually an herb of the buckwheat family, Polygonaceae, a relative of the rhubarb. Buckwheat is also gluten free, which makes it an ideal food for those allergic or sensitive to the gluten in found wheat and other true grains. After being removed from the husk, the triangular seeds are used to make flour.

Landmark varieties of wheat in India and their yielding ability

Variety	Year of release	Yield potential (Q/ha)
S 227	1965	33.7
C 306	1965	36.0
Sonalika	1967	45.5
Kalyan Sona	1970	46.0
WL 711	1975	46.8
UP 262	1977	44.0
WH 147	1977	45.1
HD 2189	1979	45.7
HD 2009	1980	45.8
Lok 1	1981	45.4
HUW 234	1984	35.3
HD 2285	1985	42.5
HD 2329	1985	47.1
UP 2338	1990	51.3
WH 542	1992	61.5
Raj 3765	1995	48.9
PBW 343	1995	63.0
HD 2687	1999	62.9
HD 2733	2001	61.5
GW 322	2002	61.0
DBW 17	2006	64.1

• The three species of wheat namely, Triticum aestivum (bread wheat), Triticum durum (macaroni wheat) and Triticum dicoccum (Emmer or Khapli) grown on commercial basis in the Indian subcontinent from pre-historic times are of spring type. 
• five important varieties namely PV 18, Kalyan Sona, Sonalika, Chhoti Lerma and Safed Lerma thereby ushering in the Green Revolution in India.

	Released by		Total
	CVRC	SVRC
Bread wheat	199	92	291
Durum wheat	27	19	46
Dicoccum wheat	04	-	04
Triticale	02	01	03
Total	232	112	344

CVRC –Central variety release committee, SVRC – State variety release committee

 

गांधीनगर

Gandhinagar pronunciation (help·info) (English: Gandhinager Hindi: गांधीनगर Gujarati: ગાંધીનગર ) is the capital of the state of Gujarat and Proved as 'Merged Capital' of India through its Connectivity with Financial Capital of India, Mumbai and Administrative Capital of Nation, Delhi, Gandhinagar is Located on the West Central point of Delhi-Mumbai Industrial Corridor.

The famous Swaminarayan temple of is built here. There was, however, tremendous political pressure to make Gandhinagar a purely Indian enterprise, partly because the state of Gujarat was the birthplace of Mahatma Gandhi. Kalia illumines Kahn's early influence in the city and his replacement by Doshi and then by American-trained H. K. Mewada, who had apprenticed with Le Corbusier in Chandigarh. Kalia shows that, unlike the other two cities, Gandhinagar would become emblematic of Gandhian ideals of swadeshi (Indigenous) goods and swaraj (self-rule)

Volga RIVER

The Volga (Russian: Волга) is the largest river in Europe in terms of length, discharge, and watershed. It flows through central Russia, and is widely viewed as the national river of Russia. Out of the twenty largest cities of Russia, eleven, including its capital Moscow, are situated in the Volga's drainage basin. Some of the largest reservoirs in the world can be found along the Volga.

MOUTH-------CASPIAN SEA

Important Rivers India

Image via Wikipedia

Important Rivers India

SNo	Name	Origin From	Falls into	Length (km)
23	Tungabhadra	Western Ghats	Krishna river	640
1	Ganges	Combined Sources	Bay of Bengal	2525
2	Satluj	Mansarovar Rakas Lakes	Chenab	1050
3	Indus	Near Mansarovar Lake	Arabian Sea	2880
4	Ravi	Kullu Hills near Rohtang Pass	Chenab	720
5	Beas	Near Rohtang Pass	Satluj	470
6	Jhelum	Verinag in Kashmir	Chenab	725
7	Yamuna	Yamunotri	Ganga	1375
8	Chambal	M.P.	Yamuna	1050
9	Ghagra	Matsatung Glacier	Ganga	1080
10	Kosi	Near Gosain Dham Peak	Ganga	730
11	Betwa	Vindhyanchal	Yamuna	480
12	Son	Amarkantak	Ganga	780
13	Brahmaputra	Near Mansarovar Lake	Bay of Bengal	2900
14	Narmada	Amarkantak	Gulf of Khambat	1057
15	Tapti	Betul Distt. In M.P.	Gulf of Khambat	724
16	Mahanadi	Raipur Distt. In Chhatisgarh	Bay of Bengal	858
17	Luni	Aravallis	Rann of Kuchchh	450
18	Ghaggar	Himalayas	Near Fatehabad	494
19	Sabarmati	Aravallis	Gulf of Khambat	416
20	Krishna	Western Ghats	Bay of Bengal	0
21	Godavari	Nasik Distt. In Maharashtra	Bay of Bengal	1465
22	Cauvery	Brahmagir Range of Western Ghats	Bay of Bengal	805

Source --http://www.winentrance.com/General_Knowledge/Geography/Important-Rivers-India.html

Related articles by Zemanta

• River Ganges (swapsushias.blogspot.com)

India space programme till now

India

home topic index

India Credit - © Mark Wade Launch Sites in India Balasore. Agency: DRDO. Type: Suborbital Launch Site. Location: Interim Test Range, Balasore Range, Chandipur-On-Sea, Orissa. Latitude: 20.9758. Longitude: 87.0491. Sriharikota. Agency: ISRO. Type: Orbital Launch Site. Location: Sriharikota Range, Andhra Pradesh. Latitude: 13.7374. Longitude: 80.2351. Thumba. Agency: ISRO. Type: Suborbital Launch Site. Location: Thumba Equatorial Rocket Launch Station, Trivandrum, Kerala. Latitude: 8.5314. Longitude: 76.8690. Rockets Developed in India Agni. - intermediate range ballistic missile - Status: Active. Two stage ballistic missile consisting of 1 x Agni + 1 x Prithvi ASLV. - all-solid orbital launch vehicle - Status: Retired 1994. GSLV. - orbital launch vehicle - Status: Active. Indian launcher for geosynchronous satellites using a Lox/LH2 upper stage developed from Russian technology. Prithvi. - short range ballistic missile - Status: Active. Single stage vehicle. First units deployed in 1995. PSLV. - all-solid orbital launch vehicle - Status: Active. Indian third-generation launch vehicle, large enough to carry polar-orbiting earth resources satellites. RH. - sounding rocket - Status: Active. Indian solid propellant sounding rocket family using indigenous rocket motors derived from French Belier / Jericho rocket engine technology. SLV. - all-solid orbital launch vehicle - Status: Retired 1983. Spacecraft Designed in India Aryabhata. - Earth Atmosphere Bhaskara. - Earth Landsat GSat. - Communications Insat 1. - Communications Insat 2. - Communications Insat 3. - Communications IRS. - Earth Landsat METSAT. - Earth Weather Orbital Vehicle. - Manned Spacecraft Rohini. - Earth Landsat Rohini 1A. - Technology Rohini 2. - Technology SRE. - Technology RV SROSS. - Earth Magnetosphere TES. - Surveillance Military Space-related People born in India Bhat. - Nagapathi Chidambar Bhat Indian Payload Specialist Astronaut. Born 1948. Chawla. - Dr Kalpana Chawla American Mission Specialist Astronaut. Born 1 July 1961. Died 1 February 2003. Number of Flights: 2.00. Total Time: 31.63 days. Malhotra. - Ravish Malhotra Indian Pilot Cosmonaut. Born 25 December 1943. Nair. - Paramaswaren Radhakrishnan Nair Indian Payload Specialist Astronaut. Born 10 October 1943. Sharma. - Rakesh Sharma Indian Pilot Cosmonaut. Born 13 January 1949. Number of Flights: 1.00. Total Time: 7.90 days.

What is the international date line and why is it necessary?

An imaginary line through the Pacific Ocean roughly corresponding to 180° longitude, to the east of which, by international agreement, the calendar date is one day earlier than to the west.

The International Date Line is the imaginary line on the Earth that separates two consecutive calendar days. That is the date in the Eastern hemisphere, to the left of the line, is always one day ahead of the date in the Western hemisphere. It has been recognized as a matter of convenience and has no force in international law.

Without the International Date Line travelers going westward would discover that when they returned home, one day more than they thought had passed, even though they had kept careful tally of the days. This first happened to Magellan's crew after the first circumnavigation of the globe. Likewise, a person traveling eastward would find that one fewer days had elapsed than he had recorded, as happened to Phileas Fogg in "Around the World in Eighty Days" by Jules Verne.

The International Date Line can be anywhere on the globe. But it is most convenient to be 180° away from the defining meridian that goes through Greenwich, England. It also is fortunate that this area is covered, mainly, by empty ocean. However, there have always been zigs and zags in it to allow for local circumstances.

bladeaxe4 " Bhuvan " - India's Very Own Google Earth READY !

As announced earlier India's own geographic information system (GIS) dubbed 'Bhuvan' is now available for download, currently under BETA release capable of Indian specific features not available in any other competing product.

Bhuvan features multiple layers of information showing topography, altitude, depth weather and other features helpful in managing public services, internal security, town planning, and infrastructure development activities.

Notes on INDIAN GEOGRAPHY for Prelims

INDIAN GEOGRAPHY
Cosmology: Science dealing with the nature and origin of the universe.
Big Bang Theory: Canon Lemaitre
Steady State Theory: Hermann Bond and Thomas Gold.
Pulsating universe theory: Allan Sandage.
One Parsec = 3.26 light years.
Hydra is the largest constellation.
When brightness of a star increases 20 magnitudes or more, it is called a supernova.
Sun accounts for 99.85% of the mass of the solar system.
Suns Revolutionary period= 250 m years
Rotation time = 25 days
Planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune
Venus and Uranus rotate anti- clockwise at their axis, whereas all other planets rotate clockwise.
Largest Terrestrial Planet:- Earth
Smallest Jovian Planet:- Neptune
Mercury and Venus have no satellites.
Jupiter has the largest rotational velocity.
Genemede of Jupiter :- Largest Satellite
Titan is the only satellite in the solar system with an atmosphere of its own.
Saturn has the least density among all the planets.
Uranus is also known as Green planet.
Greatest satellite of Neptune : Triton

Movement of the Earth.
1) Rotation: West to east in 24 hours (produces day and night) – Line separating light and dark halves is known as the circle of illumination.
2) Revolution: Movement around the sun 365 ¼ days (produces seasons) – Jan 2 : Closest to the sun- called Perihelion. July 4 : Farthest from the sun- called Apehelion.
3) Eccentricity: (Produces Ice-age and Global Warming) Shape of the earth’s orbit changes in a cyclic period running between 90,000- 1,00,000 years.
4) Precession: This is the conical motion of the axis of the spinning earth, like a spinning top. Takes about 26,000 years to complete one cycle.
Presently – pointing at Pole star.
AD 4000- pointing at Alpha cephai
A D 14,000 – pointing at Star vega
Summer Solistice: 21st June: Sun overhead at tropic of cancer.
Winter Solistice: 22nd Dec : Sun overhead at the tropic of Capricorn.
Vernal Equinox: 21st March.
Autumn Equiox: 23rd Sep
Our moon is 1/4th of the size of Earth.
Blue Moon is said to occur when the second full moon appears within the same month.
Highest Mountain on Moon: Liebnitz: 10,660m
Neil Armstrong and Edwin Aldrin: Set foot on the ocean of Tranquility
In a calendar year, a maximum of seven eclipses can occur( combining solar and lunar eclipses)
Remember 1 degree latitude or longitude represents 111 Km ( along equtor)
Longitude and Time
Rem: E-G-A [ East- gain- add]
W-L-S[ West- lose- subtract]
Earth moves 1 degree in 4 minutes.

Standard meridians differ from Greenwich Meridian by the multiples of 15degree or 7.5degree.
USA and Canada have 5 time zones.
India has one time zone.
-82.5 degree east from the Standard time
- 5 hours and 30 minutes ahead of GMT
The International Date Line:
- 180 degree Meridian is the international date line.
- A traveler crossing this date line from east to west will lose a day.
- A traveler going from west to east will gain a day

Latitudes
1. Earth Moves 1 deg in 4 minutes.
2. Standard meridians differ from Greenwich Meridian by the multiples of 15 deg or 7.5 deg.
3. USA and Canada have 5 time zones
4. India has one time zone
a. 82.5 deg E from the standard time
b. 5 hours and 30 minutes ahead of GMT

The International Date Line
1. 180 deg meridian is the international date line
2. A traveller crossing this date line from east to west will lose a day.
3. A traveller going from west to east will gain a day.

Construction of Earth's Interior
1. Relative Density= 5.5
2. Seismic Waves
a. p-waves or primary waves: Also called longitudinal or compressional waves- like sound waves- fastest
b. Secondary waves or S-waves: Also called transverse or distortional waves- like water ripples- cannot pass through liquid material.
c. Surface Waves or L waves: Long wave length waves- cause most destruction.

Earth's Surface

1. The Crust: It has two layers: Sial and Sima. These two layers extend to a distance of 30-40 km from the earth's surface. The join of Crust and Mantle is called Mohorovic Discontinuity.
2. The Mantle: It extends from 35-2900 km. The join of Mantle and Core is called the Gutenberg Discontinuity.
3. The Core: It extends from 2900-5150. It is also called NiFe because of the presence of Nikel and Iron.

Mechanical Division of Mantle
1. Lithosphere: It constitutes 80-100 km of upper most mantle. It is rigid and cool
2. Asthenosphere: It is also a part of the upper mantle. It is hot, soft and pliable.

Remember: All the meridians and only the equator form great circles.

Composition of Earth
1. Crust Composition: Oxygen: 46.8%, Silicon: 27.7%
2. Total Earth Composition: Iron: 35%, Oxygen: 30%, Silicon: 15%

Continental Drift Theory
1. According to Alfred Wegner about 250m years ago, all continents were united on a super continent called as Pangaea, which was surrounded by a large ocean called Panthalsa.

2. Continents Drifted in Two Directions:
a. Towards Equator: Due to Gravitational attraction of equatorial bulge ( caused the formation of Himalayas, Alps, and Atlas)
b. Towards West: Owing to tidal forces of moon and sun ( Caused the formation of Rockies and Andes)

Rocks, Earthquakes and Volcanism

1. About 90% of rock forming minerals are silicates.
2. Felspar is the most abundant rock forming silicate material.
3. About 75% of the surface area of the globe is covered by the sedimentary rocks while rest 25% area is occupied by the igneous and metamorphic rocks.
4. Shale is the most abundant sedimentary rock.
5. Marble is a metamorphic rock from limestone, Diamond from Carbon etc.
6. Richter Scale is used to assess the magnitude of an earthquake. It is logarithmic, it means each whole no on the scale represents a ten fold increase in the measured wave amplitude. It is a quantitative scale.
7. Intensity of earthquake is measured by Mercalli Scale. It is a qualitative scale.

Earth's Movements
1. Faults: Here the rock beds are dislocated and displaced resulting in the formation of faults.
2. Rift Valley: Is a linear depression on earth eg. Narmada and Tapti. Dead sea, the most saline lake after lake Van are situated in a rift valley.
3. 66% of the earthquakes of the world are recorded in Circum-Pacific Zone.
4. With the increasing depth, the temperature rises gradually at 1 deg C per 32 m.
5. Molten rock material below Earth's surface is called Magma, above Earth's surface is called Lava.