News: A new study has revealed how a small warm patch of water in the southeastern Arabian Sea, known as the Mini Warm Pool (MWP), helps the Indian Summer Monsoon (ISM) recover from the disruptive effects of El Niño.
About Mini Warm Pool (MWP)
- It is a small region of unusually warm sea surface water in the southeastern Arabian Sea, near the Kerala coast.
- It forms every year in April–May, just before the onset of the Indian Summer Monsoon (ISM).
- Temperature: The sea surface temperature (SST) in the MWP area often exceeds 30°C, making it the warmest region in the Arabian Sea during pre-monsoon months.
- Year-to-Year Variability: The strength and extent of the MWP vary annually, sometimes strong and widespread, other times weak or absent. Its variability is influenced by large-scale climate patterns, especially El Niño.
- Role in Monsoon Onset: The MWP induces local atmospheric convection, helping to draw southwesterly monsoon winds toward the Kerala coast. It acts as a precursor that helps initiate the Indian Summer Monsoon.
- Link with El Niño and the Indian Ocean Capacitor Effect
- El Niño peaks in the Pacific Ocean (Nov–Jan) but impacts the Indian Ocean after a delay of 4–5 months. This delayed influence is known as the Indian Ocean Capacitor Effect where the Indian Ocean “stores” El Niño’s energy and “releases” it later.
- The anomalous easterly winds generated by this effect reduce surface cooling in the southeastern Arabian Sea, intensifying the MWP.
- These easterly winds tend to delay the overall monsoon onset.
- However, the stronger MWP generated by the same winds creates local low pressure, pulling moisture-laden air toward Kerala and helping restore the monsoon’s timing.
- The MWP acts as a “self-correcting” system. It mitigates El Niño’s delaying impact on the Indian monsoon
- Importance for Forecasting
- Monitoring the MWP can reduce uncertainty in monsoon prediction and improve seasonal forecasts.
- Better forecasts benefit farmers, policymakers, and water resource managers.
- The MWP demonstrates the tight coupling between the Pacific and Indian Oceans.
- It highlights how small oceanic features can influence continental-scale weather and livelihoods of over a billion people.
