Static Quiz 13 February 2024 (Geography)   

Bhabhar-
a zone of porous and rocky soils made up of debris washed down from the higher ranges. The rivers usually disappear in this belt. The Bhabhar and the lower Shiwalik ranges have a subtropical climate. This belt is just above terai.

Terai- Above the alluvial plain lies the Terai strip, a seasonally marshy zone of sand and clay soils. The Terai has higher rainfall than the plains, and the downward-rushing rivers of the Himalaya slow down and spread out in the flatter Terai zone, depositing fertile silt during the monsoon season and receding in the dry season. The Terai has a high water table due to groundwater percolating down from the adjacent zone.

DECCAN TRAP AND ITS CHARACTERISTICS
It is the deccan plateau region which includes Kathiawar plateau of Gujarat and most of Maharashtra, south west MP and NW Karnataka. It is a volcanic plateau made up of horizontal layers of solidified lava forming trap structure which have a step like appearance. In between the layers of solidified lava, sedimentary layers are also found thus making it intertrappean in structure. The deccan plateau slopes towards east and south and descends abruptly towards west making sahayadri ranges.

Tidal or Mangrove forests: These forests grow along the coast and on the edges of the deltas e.g., the deltas of the Ganga, Mahanadi, Godavari, Krishna and Kaveri. They are called ‘Tidal Forests’. In West Bengal these forests are known as ‘Sundarbans’. The ‘sundari’ is most significant tree in these forests. The other notable trees of these forests are hogla, garan, gewa, golpata, gilepata, pasur etc. These forests are supply timber and fire wood. Palm and coconut trees adorn the coastal strip

MANGROVE FORESTS: Uses-
– Obstruct oncoming high waves and tides thus protect coastal erosion
– Absorb pollutants
– Reduce coastal erosion
– Absorb storm energy
– Rich breeding grounds for fish

Western Disturbances
 Western Disturbances develop in the mid latitude region (north of the Tropic of Cancer), not in the tropical region, therefore they are called as mid latitude storms or extra-tropical storms.
o Extra-Tropical Cyclones are also called as winter storms and blizzards.
 Western Disturbances are low pressure systems, embedded in western winds (westerlies) that flow from west to the east.
 It is a term coined by an Indian Meteorologist for the weather phenomenon which is propagated from the West.
 The phrase Western Disturbance was first used in a published literature in 1947. However, its precursor Winter Disturbance was coined earlier in 1931.
 Arrival in India
o Western Disturbances begin is a low pressure system that originates in the Mid- latitude region near the Atlantic ocean and Europe.
o The low pressure typically forms over the Mediterranean Sea and travels over Iran, Iraq, Afghanistan and Pakistan before entering India loaded with moisture.

DISTRIBUTION OF RAINFALL: The rainfall in India is seasonal, uncertain and unevenly distributed. Most of the rain comes during the South-West Monsoon period. Rainfall may be too much or too little. There are also long dry periods in between. On the basis of the quantity of rainfall, we can divide India into five major rainfall regions.
1)Very low rainfall region (Less than 30 cms per year). It is found in Karakoram ranges, northern Kashmir and western parts of Kachchh and Rajasthan (Thar desert).
2) Low rainfall region (30 cms. to 60 cms. per year). It is found in Zaskar range, parts of Punjab and Haryana, Central Rajasthan, Western Gujarat and the rain-shadow areas of the Western Ghats.
3) Moderate rainfall (60 cms. to 100 cms. per year). It is found over a greater part of India, excluding the areas of low rainfall and heavy rainfall. Most of the rain is from the South-West Monsoon winds.
4) Heavy rainfall region (100 cms. to 200 cms. per year). It is found in four separate areas, including a narrow belt of the western coast, eastern coastal belt, the foothills of the Himalayas and a part of north-east India.
5) Very heavy rainfall region (over 200 cms. per year). It is found on the western side of the Western Ghats , the foothills of Himalayas, Meghalaya plateau (Shillong plateau) and Andaman and Nicobar Islands. Mawsynram in Meghalaya plateau has recorded 1141 cms. of rainfall per year and it is the place which gets the heaviest rainfall in India/world.

Onset of the South-West Monsoon
• The location of ITCZ shifts north and south of the equator with the apparent movement of the Sun.
• During the month of June, the sun shines vertically over the Tropic of Cancer and the ITCZ shifts northwards.
• The southeast trade winds of the southern hemisphere cross the equator and start blowing in southwest to northeast direction under the influence of Coriolis force.
• These winds collect moisture as they travel over the warm Indian Ocean.
• In the month of July, the ITCZ shifts to 20°-25° N latitude and is located in the Indo-Gangetic Plain and the south-west monsoons blow from the Arabian Sea and the Bay of Bengal. The ITCZ in this position is often called the Monsoon Trough.
• The shift in the position of the ITCZ is also related to the phenomenon of the withdrawal of the westerly jet stream from its position over the north Indian plain, south of the Himalayas.
• The easterly Jet Stream (Somali Jet) sets in along 15°N latitude only after the western jet stream has withdrawn itself from the region. This easterly jet stream is held responsible for the burst of the monsoon in India.

The retreating southwest monsoon season is marked by clear skies and rise in temperature.