Daily Current Affairs : 8-November-2023

The recent analysis by the India Meteorological Department (IMD) has unveiled a concerning trend in the rainfall patterns of Southern peninsular India. With records spanning over 123 years, October emerged as the sixth driest month in its meteorological history.

Factors Influencing Rainfall Deficiency:

Confluence of Northeast Monsoon and Cyclone Hamoon: In October, the region witnessed an unusually low rainfall of 74.9mm. This was attributed to the confluence of the northeast monsoon with Cyclone Hamoon. The moisture deviation disrupted wind patterns, causing a delay in the onset of the northeast monsoon.

El Nino and Indian Ocean Dipole (IOD): The climatic conditions of 2023 are marked by El Nino, coupled with a positive phase of the Indian Ocean Dipole (IOD). This combination resulted in reduced rainfall in northern Tamil Nadu and nearby areas. Conversely, southernmost regions like Tamil Nadu and Kerala experienced more substantial rainfall during the same period.

Understanding Indian Ocean Dipole (IOD):

Positive IOD: A positive IOD occurs when the western side of the Indian Ocean becomes warmer than the eastern side, near the Somalia coast. This disrupts the normal air circulation, leading to warmer conditions along the African coast.

Negative IOD: Conversely, a negative IOD indicates cooler temperatures in the western Indian Ocean. Warmer waters from the western Pacific cause a rise in temperature in the region, reinforcing the cycle of a negative IOD.

Cyclone Hamoon’s Impact:

Cyclone Hamoon, a severe tropical cyclone, made landfall in Bangladesh on October 25, 2023. Originating from a low-pressure system in the Bay of Bengal, its impact further contributed to the region’s reduced rainfall.

El Nino’s Role:

El Nino, a climatic phenomenon characterized by warming of surface waters in the equatorial Pacific Ocean, tends to suppress monsoon rainfall in India. In 2023, the presence of El Nino exacerbated the rainfall deficiency in Southern peninsular India.

Important Points:


Key Points:

  • October 2023 – Sixth Driest Month:
    • Southern peninsular India experienced its sixth driest October in 123 years.
  • Factors Influencing Rainfall Deficiency:
    • Confluence of Northeast Monsoon and Cyclone Hamoon:
      • Unusually low rainfall (74.9mm) in October.
      • Confluence disrupted wind patterns, delaying northeast monsoon onset.
    • El Nino and Indian Ocean Dipole (IOD):
      • 2023 marked by El Nino and positive IOD.
      • Resulted in reduced rainfall in northern Tamil Nadu.
      • Southern regions (Tamil Nadu, Kerala) experienced substantial rainfall.
  • Understanding Indian Ocean Dipole (IOD):
    • Positive IOD:
      • Warm western Indian Ocean disrupts normal air circulation.
      • Warmer conditions along the African coast.
    • Negative IOD:
      • Cooler temperatures in the western Indian Ocean.
      • Warmer Pacific waters reinforce a negative IOD cycle.
  • Cyclone Hamoon’s Impact:
    • Origin and Landfall:
      • Originated from a low-pressure system in the Bay of Bengal.
      • Made landfall in Bangladesh on October 25, 2023.
  • El Nino’s Role:
    • Definition and Impact:
      • Climatic phenomenon with periodic warming of equatorial Pacific Ocean.
      • Tends to suppress monsoon rainfall in India.
      • Exacerbated the rainfall deficiency in Southern peninsular India in 2023.
Why In News

The India Meteorological Department (IMD) recent analysis regarding the rainfall patterns in Southern peninsular India, spanning 123 years of records, exposed that the region encountered its sixth driest October in its meteorological history. This unprecedented dry spell poses significant challenges for agricultural activities and raises concerns about water scarcity in the region.

MCQs about Southern Peninsular India

  1. What contributed to the delayed onset of the northeast monsoon in Southern peninsular India in October 2023?
    A. Positive Indian Ocean Dipole (IOD)
    B. Cyclone Hamoon
    C. El Nino
    D. Normal monsoon patterns
    Correct Answer: B. Cyclone Hamoon
    Explanation: The confluence of the northeast monsoon with Cyclone Hamoon disrupted wind patterns, causing a delay in the onset of the northeast monsoon.
  2. Which climatic conditions characterized the year 2023 in Southern peninsular India?
    A. La Nina and Negative IOD
    B. El Nino and Positive IOD
    C. Normal monsoon patterns
    D. Neutral conditions
    Correct Answer: B. El Nino and Positive IOD
    Explanation: These climatic conditions led to reduced rainfall in northern Tamil Nadu while the southern regions experienced more substantial rainfall.
  3. What is the primary impact of a positive Indian Ocean Dipole (IOD) on the western Indian Ocean?
    A. Cooling temperatures
    B. Weaker air circulation
    C. Warmer conditions along the African coast
    D. Increased rainfall
    Correct Answer: C. Warmer conditions along the African coast
    Explanation: In a positive IOD, the western side of the Indian Ocean becomes warmer than the eastern side, leading to warmer conditions along the African coast.
  4. How did Cyclone Hamoon contribute to the rainfall deficiency in Southern peninsular India in October 2023?
    A. Intensified monsoon winds
    B. Enhanced rainfall
    C. Disrupted wind patterns
    D. Decreased atmospheric pressure
    Correct Answer: C. Disrupted wind patterns
    Explanation: Cyclone Hamoon’s confluence with the northeast monsoon disrupted wind patterns, leading to reduced rainfall in the region.

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