Why in News?
Heavy rainfall in Gujarat erased India’s July rainfall deficit, but the overall southwest monsoon (June-September) remains below normal.
Key Highlights
- Cumulative rainfall since 1 June is 16.1% below normal.
- East & Northeast India: 31.9% rainfall deficit.
- South Peninsula: 26.8% deficit.
- Heavy rainfall in Gujarat resulted from a low-pressure system interacting with a Western Disturbance.
- Over 40,500 people were evacuated and 6,367 rescued due to flooding.
- Ahmedabad recorded 294.6 mm rainfall in 24 hours, its highest since 2000.
- Weak El Niño conditions have contributed to uneven monsoon distribution, affecting agriculture.
El Niño
- Warm phase of the El Niño-Southern Oscillation (ENSO).
- Characterised by warming of the central and eastern equatorial Pacific Ocean.
- Generally leads to weaker southwest monsoon and below-normal rainfall in India.
IMD Classification of Rainfall
- Normal: 96% to 104% of Long Period Average (LPA).
- Below Normal: 90% to 96% of LPA.
- Deficient: Less than 90% of LPA.
Southwest Monsoon
- Contributes nearly 75% of India’s annual rainfall.
- Normally spans June to September.
- Two branches:
- Arabian Sea Branch
- Bay of Bengal Branch
PYQ (2014, GS1, 10 Marks) Most of the unusual climatic happenings are explained as an outcome of the El Niño effect. Do you agree?
[2020] With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?
1.OMT is measured up to a depth of 26ºC isotherm which is 129 meters in the south-western Indian Ocean during January-March.
2.OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long-term mean.
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