NOTES : NCERT, Class XI Geography, India Physical Environment

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India

Lat 6.45 to 37.6 degree N
Long 68.7 to 97.25 degree E
Std Meridian 82.3 degree E
Difference of 2 hrs between longitudes.

Question : Despite almost equal difference of approx 30 degree between latitudes and longitudes. Why India is more than 3,000 km from North to South while less than 3,000 along east to west?

Question : India is 7th largest country. Name the six countries larger than India.
Answer : Russia, Canada, China, USA, Brazil, Australia and after India is Argentina

Question : Differentiate between a Gulf and Strait.
Answer : • A gulf is a large body of water almost encircled by land except for a small mouth that opens out to the sea. A strait is a strip of water that separates two lands or two large bodies of water. • Straits are used for navigational purposes and have played an integral part when it comes to shipping routes. Gulfs are more useful for human settlements, as such areas provide easy access to the ocean while being well protected as well.• Gulfs can be easily associated with inland bodies of water as well as the ocean. Straits are mostly discussed with regards to the ocean.

Structure and Physiography

India can be divided into three geological divisions.

  1. The Penisular Block
  2. The Himalayas and other peninuslar mountains
  3. Indo Ganga Brahmaputra plain

1. The Penisular Block

  • The northern boundary Kutch in Guj to Aravali in Delhi to Rajmahal hills, Chota Nagpur , Ganga delta
  • Rift valleys of Narmada, tapi and Mahanadi and Satpura Block mountains are example of vertical movement and block faulting.
  • Mostly consists of residual mountains like, Aravali, Nallamala hills, Mahendragiri hills, , Javadi hills, Veliconda hills, Palkonda range.
  • western Ghat are higher than eastern ghat, i.e slop from west to east
  • Only two river flow to west i.e. Narmada and Tapi
  • River flowing to east form delta

2. The Himalayas and other peninuslar mountains

  • formed mainly due to tectonic movement
  • young weak and flexible in their structure unlike rigid and stable peninsular Block
  • fast flowing rivers forming gorges, V-shape valleys etc

3. Indo Ganga Brahmaputra plain

  • formed by river action through sediments brought from Himalayas
  • are very fertile region.

India can be divided into the following five physiographic divisions:
1. The Northern and Northeastern Mountains
Consist of Greater Himalayan range, Middle Himalayas and Shiwaliks, The Northern and Northeastern Mountains may further be divided into following five :

i Kashmir or northwestern Himalayas
- Consists of ranges such as Karakoram, Ladakh, Zaskar and Pir Panjal
- Fresh water Dal Lake between greater Himalaya and Pir Panjal , Wular lakh. Salt water lake - Pangong Tso and Tso Moriri
- Glacier - Baltoro & Siachen
- Important passes Zoji La (Great Himalayas), Banihal (Pir Panjal), Photu La(Zaskar), Kardung La (Ladakh)
- Velley of Kashmir between Himalaya and Pir Panjal
- Rivers -Indus, Jhelum, Chenab.
ii Himachal and Uttaranchal Himalayas
- Consist of Greater Himalayan range, Middle Himalayas and Shiwaliks
- Range between ravi and kali rivers (tributary of Ghaghara) other rivers are beas, satluj and Yamuna.
- Tribe - Bhotia
- Bugyals are summer grassland
- Many colonial hill stations
- two distinguishing feature of this region is Shiwalik & Dun formation.
iii Darjiling and Sikkim Himalayas
- relatively small region
- absence of Shiwaliks
- Fast flowing rivers like Tista
- Lepcha tribe
- pass - Natula pass
- peak - Kanchenjunga
iv Arunachal Himalayas
- region between bhutan and Dipu pass
- Direction changed to SW to NE
- peaks - Kangtu & Namcha Barwa
- important rivers - Kameng, Subansiri, Dihang, Dibang and Lohit
- tribes - Monpa, Daffla, Abor, Mishmi, Nishi, Naga
v Eastern Hills and Mountains
- Direction north to south
- Patkai Bum, Naga Hills, Manipur Hills, Mizo or Lushai Hills
- river - Barak, Meghna, Chindwin
- lake - loktak

2. The northern plains

  • Formed by alluvial deposits brought by the rivers.
  • three major zone - Bhabar(8-10 km), Tarai(10-20 km) and alluvial plains
  • Alluvial pains can further be divided into Khadar and Bhangar

3. The Peninsular Plateau

  • The two rivers flowing towards west is Narmada and Tapti, lying a little south of the Satpura.
  • All other rivers of the Peninsula run from west to east failing into the Bay of Bengal indicating that the plateau is titled towards east.
  • The northern portion of the plateau, separated by the Vindhya Satpura ranges is known as the Central Indian plateau, while the southern portion is called the Deccan plateau.

Divided into three major groups :

i. The Deccan Plateau
-Satpura, Maikal range and Mahadeo hills forms north boundary of Deccan Plateau
- the surface of the Deccan plateau slopes down from west to east.
- On the western side lies a range of high cliffs running south to north leaving a narrow strip of plain between it and the sea called Western Ghats.
- The plateau is higher in the south being about 2000 feet in the Mysore region and about half of that in the Hyderabad.
- The Eastern Ghats, consisting of groups of low hills, is marked by several gaps through which many peninsular rivers join the Bay of Bengal.
- The hills going southwards gradually receding from the sea turn westward to join the Western Ghats at the Nilgiri.
- The plain between Eastern Ghats and the sea is wider than that of Western Ghats.
- Except the Narmada and Tapti, all the rivers of the Peninsular India run from west to east.
- Most of them rise from the Western Ghat and traversing the whole breadth of the plateau, fall in the Bay.
- Rivers : The Mahanadi forms a broad plain known as the Chattisgarh plain in the northeast and passes through Orissa, Godavari ,Krishna its tributaries Tungabhadra, Kaveri.
ii. The Central highlands
- Boundary - Aravali (west),Rajmahal(east),satpura(south)
- Slope - towards north and north eastern
- River Banas and Chambal
iii. The Northeastern Plateau
- It is extension of peninsular plateau
- Created due to movement of Indian Plate
- Huge fault between Rajmahal and Maghalaya Plateau
- Plateau - Karbi Anglong (Assam),Meghalaya Plateau - Garo, Khasi, Jaintia

4. The Indian Desert

  • northwest of Aravali hills
  • mushroom rocks , shifting dunes , Oasis
  • two parts (1) north sloping towards sindh (2) south sloping towards kachchh
  • Luni

5. The Coastal Plains
(i) Western Costal Plain

- Submerged in sea eq Dwarka
- Major ports like JLN port, Mundra, Kandla, Mazagaon, Maromagao, Mangalore, Cochin
- Divided into :
i. Kachchh - Gujrat
ii. Kathiawar - Gujrat
iii. Konkan - Maharashtra
iv. Goan Coast - Karnataka
v. Malabar Coast - Kerala
- River flowing are fast and do not form delta
- Kayals (backwater)
- narrow from middle , broader in north & south
- Western Ghat - Sahyadri(Maharashtra) , Nilgiri(TN & Karnataka), Anaimalai(kerala), Cardamom hills (kerala)
- Palghat pass between Nilgiri & Anaimalai, Bhorghat pass in Sahyadri, Kasara ghat /Thal Ghat in Sahyadri
- highest peak Anaimudi in anaimalai, second high peak - dodabetta in Nilgiri

(ii) Eastern Coastal Plain

- Broader
- develop delta
- lesser port
- emergent coast
- Eastern Ghat(low and discontinuous) - Javadi hills, palconda range, nallamala hills, mehendragiri hills

Both Ghat meet at Nilgiri hills
6. The Islands
Andaman Nicobar

- bay of Bengal
- 512 island
- Andaman - north, Nicobar- South
- Separated by 10 degree channel
- Barren island - only active volcano
- peaks - Saddle, Mt Diavolo, Mt Koyob, Mt Thuiller

Lakshadveep & Minicoy

- Arabian Sea, 280-240 km from kerela
- Coral deposit
- 36 island
- Minicoy largest
- divided by 11th degree channel (north is amini island south canannore island)
- Storm beaches

Climate of India

Indian Climate is monsoon type climate. Monsoon connotes climate associated with seasonal reversal in direction of winds, but there are regional variations.

Factors affecting climate' : Altitude, latitude, mountain and distance from sea

Air Pressure & wind :
Winter

Surface pressure and winds :
- High pressure in north and central asia. Wind flow from north into india.
- Come into contact with trade winds in NW india.
- North India till mid Ganaga thus remains dry during winters.
Upper air circulation :
- Westerlies ,bifurcate in 2 by Tibetan highland
- one flows over Tibet and another along south of Himalayas and plays role in winter
Western disturbance and tropical cyclones :
- Western cyclonic disturbances brought to India by westerlies.
- tropical cyclone originate in bay of bengal.

Summer

Surface pressure and winds :
- ITCZ shift northward ,
- create low pressure, air mass from south hemisphere rush in from SW direction
Upper air circulation :
- westerlies withdraws, easterly sets in
- upto 30 degree north
Tropical cyclones :
- easterly jet steers the tropical depression into India
- easterly responsible for burst of monsoon in India

On set of Monsoon

  • differential heating of land and water, shifting of ITCZ in North, setting of easterly and withdrawal of westerlies
  • SW monsoon is continuation of the SE trade winds deflected in Indian Sub Continent. SE trade winds are attracted due to low pressure caused by shifting of ITCZ, cross equator, caught in circulation follow SW direction
  • easterly responsible for burst of monsoon in India.

Rain Bearing Systems

Arabian Sea System
1. Western Ghat
2. along Narmada & Tapi river valleys, north mumbai
3. Strike Saurashtra Peninsula , kachchh, west Raj, Punjab along aravalis
Bay of Bengal System (Arakan Hills of Myanmar deflects monsoon to India
1. along ganga valley
2. along Brahmaputra valley

Few Terms to remember

  • Mango Shower : end of summer
  • Blossom Shower : coffee flowers blossom in kerela
  • Nor Westers : evening thunderstorms in Bengal and Assam , useful for tea, jute, rice cultivation
  • Loo : Hot dry winds in northern plains during summers
  • October Heat : high temp/ humidity after monsoon and before winters
  • El-Nino : El Niño and La Niña events occur when the Pacific Ocean and the atmosphere above it change from their neutral (‘normal’) state for several seasons. El Niño events are associated with a warming of the central and eastern tropical Pacific, while La Niña events are the reverse, with a sustained cooling of these same areas. El-nino means 'child Christ' because it appear around Christmas. Appearance of warm current off coast of Peru. It is merely extension of warm equatorial current which get replaced temporarily by cold Peruvian current/Humbolt current

8 type of Indian climate according to Koeppen's scheme

1. Amw : Monsoon with short dry season
2. As : Monsoon with dry summer
3. AW : Tropical savannah
4. BShw : semi-arid steppe climate
5. Bwhw : desert
6. Cwg : Monsoon with dry winter
7. Dfc : Cold humid winter with short summer
8. E : polar type

A: tropical, B: Dry, C: moist mild winter, D: moist cold inter, E:polar

Soil Classification

Total eight type of soil:
1. Alluvial Soil

- two types Khadar & Bhangar
- 40% area of country, whole ganga plain
- rich in potash poor in phosphorous
- sandy loam to clay

2. Black Soil

- cover most of deccan plateau
- known as regur soil or black cotton soil
- clayey, retain moisture for long time
- rich in iron, lime, magnesia, alumina, potash
- poor in phosphorous, nitrogen and organic

3. Red and Yellow Soil

- eastern and southern of deccan plateau
- low rainfall area
- red due to iron , yellow when hydrated
- poor in phosphorous, nitrogen and organic

4. Laterite Soil

- brick color soil
- found at high rainfall high temp. region
- result of intense leaching
- soil rich in iron oxide left behind
- good for cashewnut
- found in higher of peninsular region - Nilgiri, Udaipur, hills of Orrisa
- lack nitrogen, phosphate, calcium, organic
- rich in iron , potash

5. Arid Soil

- red to brown
- sandy saline
- lack moisture, nitrogen, humus
- rich in lime
- location Rajasthan

6. Saline Soil

- infertile, arid
- waterlogged, swampy
- lack nitrogen, calcium
- Gujarat
- Add gypsum to solve salinity

7. Peaty Soil

- Heavy rainfall, high humidity
- high organic matter (40-45%)
- heavy & balck
- north bihar, south uttaranchal, coastal WB, orrisa and TN

8. Forest Soil

- Low bactrical activity
- acidic with low humus
- sufficient rainfall
- Kashmir, Sikkim, Arunachal

Reference