1. (i) withdrawal or the retreat of monsoon is a more gradual process. (ii) The withdrawal of the monsoon begins in the north western states of India, by early September. (iii) By mid-October, it withdraws completely from the northern half of the peninsula. (iv) The withdrawal from the southern half ofRead more

    (i) withdrawal or the retreat of monsoon is a more gradual process.
    (ii) The withdrawal of the monsoon begins in the north western states of India, by early September.
    (iii) By mid-October, it withdraws completely from the northern half of the peninsula.
    (iv) The withdrawal from the southern half of the peninsula is fairly rapid.
    (v) By early December, the monsoon withdraws from the rest of the country.

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  2. ' (i) Normally, when the tropical eastern south pacific ocean experiences high pressure, the tropical eastern Indian ocean experiences low pressure. (ii) But in certain years, there is a reversal in the pressure conditions and the eastern pacific has low pressure in comparison to the Indian ocean. (Read more

    ‘ (i) Normally, when the tropical eastern south pacific ocean experiences high
    pressure, the tropical eastern Indian ocean experiences low pressure.
    (ii) But in certain years, there is a reversal in the pressure conditions and the eastern pacific has low pressure in comparison to the Indian ocean.
    (iii) This periodic change in pressure conditions is known as southern
    Oscillation or SO.
    (iv) The difference in pressure over Tahiti, in the pacific ocean and Darwin in northern Australia is computed to predict the intensity of the monsoon.
    (v) A feature connected with the So is the El Nino, a warm ocean current
    that flows past the peruvian coast, in place of the cold peruvian current every 2 to 5 years.
    (vi) The change in pressure conditions are connected to the El Nino. Hence,
    the phenomena is referred to as ENSO (EI Nino Southern oscillations).

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  3. (i) The differential heating and cooling of land and water creates low pressure on the landmass of India, while the seas around experience comparatively high Pressure. (ii) The shift in the position of Inter Tropical Convergence Zone (ITCZ) in summer over the Ganga plain is a trough of low pressureRead more

    (i) The differential heating and cooling of land and water creates low
    pressure on the landmass of India, while the seas around experience
    comparatively high Pressure.
    (ii) The shift in the position of Inter Tropical Convergence Zone (ITCZ)
    in summer over the Ganga plain is a trough of low pressure in the
    equatorial latitude. This is where the northeast and the southeast trade
    winds converge.
    (iii) The presence of the high pressure, area, east of Madagascar also affects
    the Indian monsoons.
    (iv) The Tibetan plateau gets intensely heated during summer, which results
    in the formation of low pressure area over the plateau.
    (v) The movement of the westerly jet streams to the north of the Himalayas
    and the presence of tropical easterly jet streams over the Indian Peninsula
    during summers, also affects the mechanism of monsoon.

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  4. Jet streams are fast flowing winds moving in the upper air of the atmosphere. (i) Sub-tropical Westerly Jet Streams: These jet streams are located approximately over 27'-30' north latitude; therefore, they are known as sub-tropical westerly jet streams. over India, these jet streams blow south of thRead more

    Jet streams are fast flowing winds moving in the upper air of the atmosphere.
    (i) Sub-tropical Westerly Jet Streams: These jet streams are located
    approximately over 27′-30′ north latitude; therefore, they are known
    as sub-tropical westerly jet streams. over India, these jet streams blow
    south of the Himalayas all through the year except in summer. During
    winters, the cyclonic disturbances are brought into India by these jet
    streams.
    (ii) Tropical-easterly Jet Streams: These easterly jet streams blow over
    peninsular India, approximately over l4’N, during the summer months.
    it is believed to be responsible for the sudden outbreak of the south-west
    monsoon in India.

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  5. (i) During winter, a high pressure area develops north of the Himalayas. (ii) Cold dry winds blow from this region to the iow pressure areas over the oceans to the south. (iii) In summer, a low pressure area develops over interior Asia as well as over northwestern India. (iv) This causes a completeRead more

    (i) During winter, a high pressure area develops north of the Himalayas.
    (ii) Cold dry winds blow from this region to the iow pressure areas over the
    oceans to the south.
    (iii) In summer, a low pressure area develops over interior Asia as well as
    over northwestern India.
    (iv) This causes a complete reversal of the direction of winds during
    summer.
    (v) Air moves from the high pressure area over the southern Indian ocean
    in a south-westerly direction, crosses the equator and turns right towards
    the low Pressure area over the Indian sub-continent.
    (vi) These winds are known as south-west monsoon winds.
    (vii) These winds blow over the warm oceans, gather moisture and bling
    widespread rainfall over the mainland of India.

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