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GS Paper: GS1-15.Geographical features and their location- Changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.

  • Tornado’s dynamics and its India connection

    Babu ChunderSikur Chatterjee’s paper was the earliest record of a tornado’s dynamics in the history of meteorology, according to a study.

    Try this PYQ:

    Q. In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason? (CSP 2015)

    (a) Sea surface temperatures are low

    (b) Inter-Tropical Convergence Zone seldom occurs

    (c) Coriolis force is too weak

    (d) Absence of land in those regions

    What is a Tornado?

    • A tornado is a rapidly rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud.
    • The windstorm is often referred to as a twister, whirlwind or cyclone winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern.
    • Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it.
    • It is generally accompanied by extreme weather such as heavy downpours, hail storms, and lightning.

    Who was Babu ChunderSikur Chatterjee?

    • Chatterjee was an Indian scientist employed with the Surveyor General of India during the British colonial era.
    • He was likely the first person to scientifically document a tornado’s path in 1865, a study from the Indian Institute of Tropical Meteorology (IITM), Pune, has claimed.
    • Chatterjee had published his findings in a journal named Proceedings of the Asiatic Society of Bengal, in a paper titled ‘Note on a whirlwind at Pundooah’, near Hooghly.
    • The paper described a tornado’s dynamics in meticulous detail and was accompanied by a sketch that mathematically depicted its scale, track and rotation.

    His work

     

    • Chatterjee quantitatively mapped the entire trail of á tornado’s destruction.
    • He benefited from the rare opportunity to observe a tornado passing through a railway track where there were conveniently placed markers at predefined locations.
    • This enabled him to observe and make clear measurements of the tornado’s direction, dynamics and path.

    Back2Basics

  • [pib] Himalayan Geothermal Springs release huge amount of carbon dioxide in the atmosphere

    The Himalayas, which hosts about 600 geothermal springs needs to be considered while estimating emissions to the carbon cycle and thereby to global warming says, Indian researchers.

    Note the following hot springs in India:

    1) Panamik in Nubra valley

    2) Kheer Ganga in Kullu, Himachal

    3) Manikaran Sahib, Himachal

    4) Tattapani, Chhattisgarh

    5) Gaurikund, Uttarakhand

    6) Yumthang, Sikkim

    7) Reshi, Sikkim

    Geothermal springs

    • Geothermal or Hot springs are heated by shallow intrusions of magma (molten rock) in volcanic areas. Some thermal springs, however, are not related to volcanic activity.
    • The water is heated by convective circulation: groundwater percolates downward & reaches depths of a kilometre or more where the temperature of rocks is high because of the normal temperature gradient of the Earth’s crust.

    Why consider the Himalayas?

    • The Himalayan geothermal springs which cover about 10,000 square km in the Garhwal region of Himalaya show a significant discharge of CO2 rich water.
    • The estimated carbon dioxide degassing (removal of dissolved gases from liquids, especially water or aqueous solutions) flux is nearly 7.2 ×106 mol/year to the atmosphere.
    • Such CO2 degassing should be taken into account to assess global carbon outflux in the earth’s atmosphere.

    Where does this CO2 come from?

    • Carbon outflux from Earth’s interior to the exosphere through volcanic eruptions, fault zones, and geothermal systems contribute to the global carbon cycle that effects short and long term climate of the Earth.
    • The CO2 in the thermal springs are sourced from metamorphic decarbonation of carbonate rocks present deep in the Himalayan core along with magmatism and oxidation of graphite.
    • Most of the geothermal water is dominated by evaporation followed by weathering of silicate rocks.
    • Isotopic analyses further point towards a meteoric source for geothermal water.

  • In news: Mount Sinabung

    The Mount Sinabung volcano in Indonesia has erupted spouting ash at least 5,000 metres high into the sky.

    In the Philippines, a volcano called Taal on the island of Luzon; 50 km from Manila has recently erupted in January. Note all such recent eruption in news.

    Also, try this PYQ:

    Consider the following statements:

    1. The Barren Island volcano is an active volcano located in the Indian Territory.
    2. Barren Island lies about 140 km east of Great Nicobar
    3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.

    Which of the statements given above is/are correct? (CSP 2018)

    (a) 1 only

    (b) 2 and 3 only

    (c) 3 only

    (d) 1 and 3

    Mount Sinabung

    • It is a Pleistocene-to-Holocene stratovolcano in the Karo plateau of Karo Regency, North Sumatra, Indonesia.
    • It is created by the subduction of the Indo-Australian Plate under the Eurasian Plate.
    • It erupted in 2010 after a 400-year-long hiatus and has been continuously active since September 2013.

  • Boreal Summer Intra-Seasonal Oscillation (BSISO)

    Researchers at the Indian National Centre for Ocean Information Services (INCOIS), Hyderabad have reportedly found a way to better forecast the Boreal Summer Intra-Seasonal Oscillation (BSISO).

    Try this PYQ:

    Q.With reference to ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? (CSP 2017)

    1. IOD phenomenon is characterized by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
    2. An IOD phenomenon can influence an El Nino’s impact on the monsoon.

    Select the correct answer using the code given below:

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2

    What is BSISO?

    • The BSISO of the Asian summer monsoon (ASM) is one of the most prominent sources of short-term climate variability in the global monsoon system.
    • It is the movement of convection (heat) from the Indian Ocean to the western Pacific Ocean roughly every 10-50 days during the monsoon (June-September).
    • Compared with the related Madden-Julian Oscillation (MJO) it is more complex in nature, with prominent northward propagation and variability extending much further from the equator.
    • It represents the monsoon’s ‘active’ and ‘break’ periods, in which weeks of heavy rainfall give way to brilliant sunshine before starting all over again.
    • The active phase also enhances monsoon winds and hence the surface waves.

    Why predict BSISO behaviour?

    • Some phases of boreal summer intraseasonal oscillation or BSISO induce high wave activity in the north Indian Ocean and the Arabian Sea, the researchers claimed.
    • Wave forecast advisories based on the BSISO would be more useful for efficient coastal and marine management.
    • This finding has a great significance in developing seasonal and climate forecast service for waves and coastal erosion for India.

  • [pib] Tuting-Tidding Suture Zone (TTSZ)

    Earthquake prone zones in India:

  • What is Seismic Noise?

    The seismic noise level has dropped by as much as 50 per cent between March and May due to lockdowns this year, according to researchers.

    Ever heard of space-based monitoring of seismic activities?  This topic creates a scope for potential prelims question…

    What is Seismic Noise?

    • Seismic noise refers to vibrations within the Earth, which are triggered by natural and man-made phenomena like earthquakes, volcanoes and bombs.
    • Seismometers, specialised devices that record ground motions, also capture seismic noise.
    • Everyday human activity — such as road traffic, manufacturing in factories, the sound produced by planes roaring overhead, or simply people walking down the street.
    • The sound signals created by human beings are often referred to as anthropogenic seismic noise.
    • Seismic noise acts almost like background sound for seismologists — it is the unwanted component of signals recorded by a seismometer.

    Variations in noise levels

    • The level of anthropogenic seismic noise recorded varies based on a number of factors.
    • Highly-populated urban areas will generate more vibrations from human activity than less densely populated regions.
    • Timing too plays an important role. The degree of seismic noise is found to be much lower during public holidays.

    Why is this important to record this noise?

    • Due to this, scientists will be able to spot weaker signals.
    • Such small signals tell us about a geological fault making seismic hazard assessment more accurate.
    • This means that scientists will have a better shot at monitoring a whole range of seismogenic behaviour, including the smallest earthquakes or the early signs of a volcanic eruption.

  • [pib] Ravines of Chambal-Gwalior Region

    Union Minister of Agriculture & Farmers’ Welfare held a meeting with World Bank representatives to bring large Ravines of Gwalior–Chambal region under agriculture.

    Try this question for mains:

    Q.What is Badland Topography? Discuss the scope of their utilization as arable land in India.

    What are Ravines?

    • Badland topography is a major feature of the Chambal valley is characterized by an undulating floodplain, gullies and ravines.
    • Ravines are a type of fluvial erosional feature and are formed as a result of constant vertical erosion by streams and rivers flowing over semi-arid and arid regions.

    How are they formed?

    • Researchers consider the regional climate as a major factor in the formation of ravines.
    • Climate indeed plays a huge role by supplying the water in the form of rain or snow as well as providing the temperature variations.
    • However, the ravines of Chambal are a bit difficult to be explained solely on climatic terms.
    • The region through which the Chambal River flows does not receive enough rainfall to create ravines that are 60–80 m deep.
    • Researchers have attributed neotectonic activities to the Chambal ravines genesis.

    Other factors

    • It is well known that rivers are full of energy and actively erode in their initial phases and progressively become passive as they attain their base levels.
    • But sometimes, due to tectonic movements, the base level may be lowered further thus energizing the river and reactivating the erosion. This is known as River Rejuvenation.
    • Moreover, wind erosion has also contributed to the formation of Chambal ravines.

    Back2Basics: What are Badlands?

    • Badlands are erosional landforms of highly dissected morphology that are created on soft bedrock in a variety of climate conditions.
    • They develop in arid to semiarid areas where the bedrock is poorly cemented and rainfall is generally heavy and intermittent.
    • The dry, granular surface material and light vegetation are swept from the slopes during showers, leaving the gullies bare.

  • Mapping: Islands of Polynesia

    How did the Polynesian peoples come to live on the far-flung islands of the Pacific? The question has intrigued researchers for centuries.

    The newscard contains some trivial facts. However, aspirants are advised to observe the map.

    Study on Polynesia

    • Norwegian explorer Thor Heyerdahl brought the topic to public attention when he sailed a balsa-wood raft called the Kon-Tiki from Peru to Polynesia in 1947.
    • His goal was to demonstrate such voyages were possible, supporting theories linking Polynesian origins to the Americas.
    • Decades of research in archaeology, linguistics and genetics now show that Polynesian origins lie to the west, ultimately in the islands of Southeast Asia.

    New evidence for American interlopers

    • A new study published in Nature reports genetic evidence of Native American ancestry in several Polynesian populations.
    • Other researchers have previously found evidence of indigenous American DNA in the genomes of the modern inhabitants of Rapa Nui.
    • Rapa Nui, also known as Easter Island, is the part of Polynesia closest to South America.
    • This suggests the “Amerindian” genetic component was likely introduced later via Chilean colonists.

  • ‘Churachandpur Mao Fault’ in Mizoram

    Mizoram’s zone of “scary” earthquakes is caught between two subterranean faults called the ‘Churachandpur Mao Fault’.

    Try this question from CSE Mains 2014:

    Q.Why are the world’s fold mountain systems located along the margins of continents? Bring out the association between the global distribution of Fold Mountains and the earthquakes and volcanoes.

    Churachandpur-Mao Fault (CMF)

    • The CMF is named after two places in Manipur and runs north-south into Myanmar along the border of Champhai.
    • The Mat Fault runs northwest-southeast across Mizoram, beneath river Mat near Serchhip.
    • It is defined by straight valleys; most prominent being between Kangpokpi and Maram region of Mizoram.
    • The fault takes a north-easterly trend from Maram where the fault zone is characterized by active landslides during the monsoon.

    Why study CMF?

    • Faults are discontinuities or cracks that are the result of differential motion within the earth’s crust.
    • Vertical or lateral slippage of the crust along the faults causes an earthquake.

  • Rapid Intensification of Cyclones

    Tropical cyclones remain the deadliest natural climate hazard that causes an unacceptably high loss of life, property and infrastructure.  Global warming has already resulted in a detectable increase in the number of higher intensity cyclones as well as their intensification.

    Also read:

    [Burning Issue] Tropical Cyclones and India

    Try this question:

    Q. The Marsupial Theory often seen in news is related to which of the climatic phenomena?

    a) Heatwaves b) Monsoon Variability c) Formation of Cyclones d) Thunderstorms

    What is Rapid Intensification of Cyclones?

    • RI is defined as an increase in maximum sustained winds by at least 55 km/hour in a 24-hour period.
    • Such acceleration can only come with a rapid drop in the pressure in the eye of the cyclone.
    • Rapid intensification (RI) is making cyclone forecasts harder and intense cyclones with RI are expected to grow in number.
    • The lack of understanding of the transition from a seedling of a cyclone, like a low-pressure system to a tropical storm, limits extending the forecast lead times.

    Factors causing RI

    The most important environmental factors for cyclone genesis are-

    • the rotation or vorticity of a low-pressure system at the surface;
    • sea surface temperatures or the volume of warm water available;
    • the vertical motion of air in this low-pressure system;
    • the amount of humidity available in the middle atmosphere and
    • the vertical shear or the change in winds from the surface to the upper atmosphere.

    MJO and Cyclones

    • Madden-Julian Oscillations as they are known, dominate the tropics during October-April by propagating from the western Indian Ocean into the eastern Indian Ocean, across the Indonesian seas into the Pacific Ocean.
    • Referred to as MJOs, these Madden-Julian Oscillations throw seeds of rotational low-pressure systems over the Indian and the Pacific Oceans.
    • And thus, MJOs show a strong association with cyclogenesis, especially for the post-monsoon season.

    Impacts of MISO

    • Monsoon Intraseasonal Oscillations (MISO) are alternating periods of heavy and minimal rainfall, each lasting for about a month or so and tending to follow a cyclical, northward shifting pattern from the equator to southern Asia.
    • While the strong vertical shear suppresses cyclones during the monsoon season, MISOs influence cyclone genesis during the pre-monsoon season.

    Other factors

    • At longer timescales, phenomena like the El Niño and La Niña influence not only the number of cyclone seeds but also the location and the expanse of warm water.
    • For example, during the pre-monsoon season of La Niña year, the region of warm water over the Bay of Bengal increases. This leads cyclones to travel longer and grow stronger than during an El Niño year.
    • Over the Pacific Ocean, on the other hand, it is the El Niño that provides a larger swath of warm water and more intense cyclones.
    • West Africa produces waves called easterly waves that propagate west from land onto the tropical Atlantic Ocean and sow the seeds for most hurricanes.
    • Extensive analysis has produced theories that are evocatively called the Marsupial Theory — a wave pouch that allows cyclones to grow, or waves interacting to produce a Kelvin cat’s eye, which is a ‘sweet-spot’ for the birth of a cyclone.