INDIAN RIVER SYSTEM

INDIAN RIVER SYSTEM

The Himalayan River System

Ganga River System

The Ganga (or Ganges) and its tributaries like Yamuna, Son, and Gandak, which have been left out of the list, actually formulates the biggest cultivable plains of north and eastern India, known as the Gangetic plains. The main river, the holy Ganga forms by the joining of the Alaknanda River and Bhagirathi River at Devprayag. The Bhagirathi, which is considered the Ganga's true source, starts from Gomukh Gangotri glaciers in the Himalayas and flows through the states of Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, and West Bengal, after which it enters Bangladesh. Known as the Padma River in Bangladesh, it joins theJamuna River, the largest distributary of the Brahmaputra River. The Padma then joins the Meghna River before emptying into the Bay of Bengal in Bangladesh. With a length of about 2,525 kilometres (1,569 mi), the Ganga the second longest river of India. The Brahmaputra is longer, but most of its course it not in India.

Indus River System

The Indus River originates in the northern slopes of the Kailash range near Lake Mansarovar in Tibet. Although most of the river's course runs through neighboring Pakistan, a portion of it does run through Indian territory, as do parts of the courses of its five major tributaries, listed below. These tributaries are the source of the name of the Punjab region of South Asia; the name is derived from the Persian words Punj ("five") and aab ("water"), hence the combination of the words (Punjab) means "five waters" or "land of five waters".

Beas

The Beas originates in Bias Kund, lying near the Rohtang pass. It runs past Manali and Kulu, where its valley is known as the Kulu valley. It joins the Sutlej river near Harika, after being joined by a few tributaries. The total length of the river is 615km. Flowing west, it enters India in the Ladakh district of Jammu and Kashmir.

Chenab

The Chenab originates from the confluence of two rivers, the Chandra and the Bhaga, It is also known as the Chandrabhaga in Himachal . It runs parallel to the Pir It enters the plains of Punjab near Akhnur and is later joined by the Jhelum. It is further joined by the river Ravi and the Sutlej in Pakistan.

Jhelum

The Jhelum originates in the south-eastern part of Jammu and Kashmir, in a spring known as verinag. One of its important tributaries is Krishna-Ganga.

Ravi

The Ravi originates near the Rothang pass in the Himalayas and follows a north-westerly course. It turns to the south-west, near Dalhousie, and then cuts a gorge in the Dhaola Dhar range entering the Punjab plain near Madhopur. It flows as a part of the Indo-Pakistan border for some distance before entering Pakistan and joining the Chenab river.

Sutlej (Satluj)

The Sutlej originates from the Rakas Lake (Rakshas Tal), which is connected to the Manasarovar lake by a stream, in Tibet. It enters Pakistan near Sulemanki, and is later joined by the Chenab. It has a total length of almost 1500 km. First village were it enters in India is Namgiya.

The Brahmaputra River System

The Brahmaputra originates in China, near the sources of the Indus and the Sutlej. It is about 2,900 kilometres (1,800 mi) long. In China, where it is known as the Yarlung Zangbo River, or Tsangpo, it flows east, parallel to the Himalayas. Reaching Namjagbarwa, it turns south and enters India in Arunachal Pradesh, where is it known as Dihang. In Assam it is called the Brahmaputra. Just before entering Bangladesh it splits into two distributaries, the larger of which is called the Jamuna River.

The Peninsular River System

The Narmada River System

The Narmada' or Nerbudda is a river in central India. Like the Mahi, it runs from east to west. The Narmada originates in Amarkantak .

The Tapi/Tapti River System

The Taapi is the ancient name of the river now called "Tapti" of central India. It is one of the major rivers of peninsular India with the length of around 724 km, It rises in the eastern Satpura Range of southernMadhya Pradesh state, before emptying into the Gulf of Cambay of the Arabian Sea, in the State of Gujarat.

The Godavari River System

The river with second longest course within India, Godavari is often referred to as the Vriddh (Old) Ganga or the Dakshin (South) Ganga. The river is about 1,450 km (900 mi) long. It rises at Trimbakeshwar, nearNasik and Mumbai (formerly Bombay) in Maharashtra around 380 km distance from the Arabian Sea, and empties into the Bay of Bengal. At Rajahmundry, 80 km from the coast, the river splits into two streams(Vasista which flows to Narsapur & Gautami which flows to other side pasarlapudi) thus forming a very fertile river delta delta.Also the Rjohi plays a very important role in the water system most of Indias rivers empty into the Rjohi including the Godavari River.

The Krishna River System

The Krishna is one of the longest rivers of India (about 1300 km in length). It originates at Mahabaleswar in Maharashtra and meets the sea in the Bay of Bengal at Hamasaladeevi in Andhra Pradesh. The Krishna River flows through the states of Maharashtra, Karnataka and Andhra Pradesh.

The Kaveri River System

The Kaveri (also spelled Cauvery or Kavery) is one of the great rivers of India and is considered sacred by the Hindus.this is the [holy river] of south Indians . birth place of river kaveri called as [Dakshin Kashi] ( god shiva temple called [Bhagandeshwar] at [Bhagamandala] and caveri temple at [talakaveri] . The headwaters are in the Western Ghats range of Karnataka state, and from Karnataka through Tamil Nadu. It empties into the Bay of Bengal.

The Mahanadi River System

The Mahanadi River Delta in India is a basin of deposit that drains large land mass of the Indian subcontinent into the Bay of Bengal. The alluvial valley is wide and relatively flat with a meandering river channel that changes its course.

The Mahanadi River flows slowly for 560 miles (900 km) and has an estimated drainage area of 51,000 square miles (132,100 square km). It deposits more silt than almost any other river in the Indian subcontinent

El Nino and La Nina Overview

El Nino and La Nina Overview 

El Nino is a regularly occurring climatic feature of our planet. Every two to five years, El Nino reappears and lasts for several months or even a few years. El Nino takes place when warmer than usual sea water exists off the coast of South America. El Nino causes climate effects around the world. 
Peruvian fishermen noticed that the arrival of El Nino often coincided with the Christmas season so named the phenomenon after the "the baby boy" Jesus. The warmer water of El Nino reduced the number of fish available to catch. The warm water that causes El Nino is usually located near Indonesia during non-El Nino years. However, during periods of El Nino the water moves eastward to lie off the coast of South America. 
El Nino increases average ocean surface water temperature in the region. This mass of warm water is what causes climatic change around the world. Closer to the Pacific Ocean, El Nino causes torrential rains across the west coast of North America and South America. 
Very strong El Nino events in 1965-1966, 1982-1983, and 1997-1998 caused significant flooding and damage from California to Mexico to Chile. Effects of El Nino are felt as far away from the Pacific Ocean as Eastern Africa (there is often reduced rainfall and thus Nile River carries less water). 
An El Nino requires five consecutive months of unusually high sea surface temperatures in the Eastern Pacific Ocean off the coast of South America to be considered an El Nino. 

La Nina

Scientists refer to the event when exceptionally cook water lies off the coast of South America as La Nina or "the baby girl." Strong La Nina events have been responsible for the opposite effects on climate as El Nino. For example, a major La Nina event in 1988 caused significant drought across North America. 

El Nino's Relationship to Climate Change

As of this writing, El Nino and La Nina do not appear to be significantly related to climate change. As mentioned above, El Nino is a pattern that had been noticed for hundreds of years by South Americans. Climate change may make the effects of El Nino and La Nina stronger or more widespread, however. 
A similar pattern to El Nino was identified in the early 1900s and was called the Southern Oscillation. Today, the two patterns are known to be pretty much the same thing and so sometimes El Nino is known as El Nino/Southern Oscillation or ENSO
FOR 3D PRESENTATION OF EL NINO AND LANINA EFFECT PLEASE CLICK THE LINK  .
(http://esminfo.prenhall.com/science/geoanimations/animations/26_NinoNina.html )

OCEAN CURRENTS

OCEAN CURRENTS :-  

An ocean current is any more or less permanent or continuous, directed movement of ocean water that flows in one of the Earths oceans. The currents are generated from the forces acting upon the water like the earths rotation, the wind, the temperature and salinity differences and the gravitation of the moon.

Ocean currents can flow for thousands of kilometers. They are very important in determining the climates of the continents,especially those regions bordering on the ocean.

Direction
Surface ocean currents are generally wind driven and develop their typical clockwise spirals in the northern hemisphere and counter-clockwise rotation in the southern hemisphere because of the imposed wind stresses. In wind driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. The areas of surface ocean currents move somewhat with the seasons; this is most notable in equatorial currents.

Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation, also known as the oceans conveyor belt, refers to the deep ocean density-driven ocean basin currents.

Ocean currents are measured in Sverdrup with the symbol Sv, where 1 Sv is equivalent to a volume flow rate of 106 cubic meters per second.

Warm ocean currents are corridors of warm water moving from the tropics poleward  where they release energy to the air. Cold ocean currents are corridors of cold water moving from higher latitudes toward the equator. They absorb energy received in the tropics thus cooling the air above.

                           

                             MAJOR OCEAN CURRENTS

Current	Ocean	Type
Agulhas Current	Indian	Warm
Alaska Current	North Pacific	Warm
Benguela Current	South Atlantic	Cool
Brazil Current	South Atlantic	Warm
California Current	North Pacific	Cool
Canaries Current	North Atlantic	Cool
East Australian Current	South Pacific	Warm
Equitorial Current	Pacific	Warm
Gulf Stream	North Altantic	Warm
Humboldt (Peru) Current	South Pacific	Cool
Kuroshio (Japan) Current	North Pacific	Warm
Labrador Current	North Atlantic	Cool
North Atlantic Drift	North Atlantic	Warm
North Pacific Drift	North Pacific	Warm
Oyashio (Kamchatka) Current	North Pacific	Cool
West Australian Current	Indian	Cool
West Wind Drift	South Pacific	Cool

El Nino and La Nina
Peruvian fisherman in the late 1800s named the seasonal swing of ocean water "El Niño" (Spanish for the "Christ Child") as it usually occurred around Christmas. A periodic weakening of the trade winds in the central and western Pacific allows warm water to invade the eastern Pacific. Along the Peruvian coast, the encroaching warm water displaces the nutrient-rich north-flowing cold ocean current causing a decline in fisheries. Today, the phenomenon is known as the " El Niño/Southern Oscillation" and we are coming to understand how this change in the seasonal wind and ocean circulation impacts global weather patterns (See December - February conditions; June - August conditions). Cooler than normal ocean temperature in this region is called "La Niña". It too has significant impacts on worldwide weather.

Horse Latitudes

Horse Latitudes

·                                    Horse latitudes, two belts of latitude where winds are light and the weather is hot and dry. They are located mostly over the oceans, at about 30° lat. in each hemisphere, and have a north-south range of about 5° as they follow the seasonal migration of the sun. 

·                                    The horse latitudes are associated with the subtropical anticyclone and the large-scale descent of air from high-altitude currents moving toward the poles.

·                                    After reaching the earth's surface, this air spreads toward the equator as part of the prevailing trade winds or toward the poles as part of the westerlies. 

·                                    The belt in the Northern Hemisphere is sometimes called the “calms of Cancer” and that in the Southern Hemisphere the “calms of Capricorn.

·                                    ” The term horse latitudes supposedly originates from the days 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.

ANTARCTIC CIRCLE

The area south of the Antarctic Circle is known as the Antarctic, and the zone immediately to the north is called theSouthern Temperate Zone. The equivalent line of latitude in the northern hemisphere is the Arctic Circle.

Every place south of the Antarctic Circle experiences a period of twenty-four hours' continuous daylight at least once per year, and a period of twenty-four hours' continuous night time at least once per year. That is to say, there is at least one whole day during which the sun does not set, and at least one whole day during which the sun does not rise. On the Antarctic Circle these events occur, in principle, exactly once per year, at the December and June solsticesrespectively. This happens because the Earth's axis is tilted, by approximately 23.5 degrees, relative to ecliptic (the plane of the Earth's orbit around the sun). At the southern winter solstice, the southern hemisphere is tilted away from the Sun to its maximum extent, and the region of permanent darkness reaches its northern limit; at the southern summer solstice, the southern hemisphere is tilted towards the Sun to its maximum extent, and the region of permanent sunlight reaches its northern limit.

In practice several other factors affect the appearance of continuous day or night, the most important being atmospheric refraction, the altitude of the observer above sea level, mirages, and the fact that the sun is a sphere rather than a point. Mirages on the Antarctic continent tend to be even more spectacular than in Arctic regions, creating, for example, a series of apparent sunsets and sunrises while in reality the sun remains under the horizon.

Due to gradual changes in the tilt of the Earth's axis, the Antarctic Circle is slowly moving. See circles of latitude

DEMOGRAPHY

·                                    The continent of Antarctica forms a land mass covering much of the area within the Antarctic Circle. There is no permanent human population on Earth south of the Antarctic Circle. 

·                                    There are, however, several Antarctic research centers from various nations that are inhabited by teams of scientists that rotate on a seasonal basis. 

·                                    In previous centuries, some semi-permanent whaling stations were established on the continent and some of the whalers would live there for a year or more. 

·                                    At least three children have been born in Antarctica, albeit in stations north of the Antarctic Circle. See Demographics of Antarctica.Starting at the Prime Meridian and heading eastwards, the Antarctic Circle passes through:.

DESERTS

DESERTS 

Deserts are found across our planet along two fringes parallel to the equator at 25–35° latitude in both the northern and southern hemispheres. Deserts are arid or dry regions and receive less than 10 inches of rain per year. Biologically, they contain plants and animals adapted for survival in arid environments. Physically they are large areas with a lot of bare soil and low vegetation cover. The world’s deserts occupy almost one-quarter of the earth’s land surface, which is approximately 20.9 million square miles.

The Mojave Desert is so diverse that it is subdivided into five regions: northern, south-western, central, south-central, and eastern. Elevations range from below sea level at Death Valley National Park to 2.26 miles on Mt. Charleston in the Spring Range of Nevada.

Deserts receive little rainfall, however, when rain does fall, the desert experiences a short period of great abundance. Plants and animals have developed very specific adaptations to make use of these infrequent short periods of great abundance.

Desert Formation

Deserts landscapes are more diverse than many expect. Some are found on a flat shield of ancient crystalline rocks hardened over many millions of years, yielding flat deserts of rock and sand such as the Sahara. Others are the folded product of more recent tectonic movements, and have evolved into crumpled landscapes of rocky mountains emerging from lowland sedimentary plains, as in Central Asia or North America .

Types of Habitat

Hot and dry deserts
The hottest type of desert, with parched terrain and rapid evaporation. In the hot and dry desert soils are course-textured, shallow, rocky or gravely with good drainage and have no subsurface water. They are coarse because there is less chemical weathering. The finer dust and sand particles are blown elsewhere, leaving heavier pieces behind.

Semi arid desertsCool coastal deserts
These deserts are located within the same latitudes as subtropical deserts, yet the average temperature is much cooler because of frigid offshore ocean current. In the coastal desert the soil is fine-textured with a moderate salt content. It is fairly porous with good drainage.

Deserts that are marked by stark temperature differences from season to season, ranging from 100° F in the summer to 10° F in the winter. In the semi-arid deserts the soil can range from sandy and fine-textured to loose rock fragments, gravel or sand.

Polar regions are also considered to be deserts because nearly all moisture in these areas is locked up in the form of ice.

Desert Locations

Most large deserts are found away from the coasts, in areas where moisture from the oceans rarely reaches. Some deserts, however, are located on the west coasts of continents, such as the Namib in Africa, or the Atacama in Chile, forming coastal fog-deserts whose aridity is the result of cold oceanic currents.

The deserts of the world occur in six global bio-geographical realms:

§      Afrotropic deserts are found in the sub-Saharan part of Africa, and in the southern fringe of the Arabian Peninsula. Pressures on the ecosystem from humans are relatively high, especially in the Horn of Africa and Madagascar.

§      The Australasian deserts comprise a series of lowland arid ecoregions in the Australian heartland. Hardly inhabited, their mean population density is less than 1 person per square kilometer. They have by far, the lowest human footprint among the global deserts.

§      The Indo-Malay region has two hot lowland deserts: the Indus Valley and the Thar. These are the deserts with the most intense human use in the world.

§      The Nearctic deserts cover 1.04 million square miles in North America. Because of the growth of large urban conglomerates such as Phoenix in the United States, their mean population density is high.

§      The Neotropic deserts in South America cover 684,000 million square miles, of which only 6 per cent receives legal protection..

§      By far, the Paleartic realm concentrates the largest set of deserts in the world, covering a remarkable 9.9 million square miles that total 63 per cent of all deserts on the planet and are known for their sheer inaccessibility and extreme aridity. The Sahara occupies 9 million square miles, or 10 per cent of the African continent. In contrast, the deserts of Central Asia have folded mountains with high landscape heterogeneity and enclosed basins.

§      Desert Animals

Birds and large mammals can escape critical dry spells by migrating along the desert plains or up into the mountains. Smaller animals cannot migrate but regulate their environment by seeking out cool or shady places. In addition to flying to other habitats during the dry season, birds can reduce heat by soaring. Many rodents, invertebrates, and snakes avoid heat by spending the day in caves and burrows searching out food during the night. Animals active in the day reduce their activities by resting in the shade during the hotter hours.

Threats

§        Military activities and off-road vehicles do cause extensive, lasting damage to the fragile desert cover.

§        Although mining activities affect small areas directly, they have significant impacts on surrounding areas.

§        Grazing pressure on the desert, and especially on the desert margin, is the most extensive agent of land degradation

§        The impacts of changes in precipitation and temperature patterns due to global climate change will be highly variable from one region to the next, but they are likely to be felt the hardest in desert margins and in desert montane areas, as these are where the principal arid rangelands are located.