ENVIRONMENT GEOGRAPHY TERMS-5

PRERNA FOR IAS

         Mehnat Aapki, Guidance Humari

         Roz ki Prelims Practice — Experts ke Saath

ENVIRONMENT GEOGRAPHY TERMS-5

1. El Niño

El Niño is a climate phenomenon characterized by the unusual warming of sea surface temperatures in the central and eastern tropical Pacific Ocean. It occurs every 2–7 years and is part of the El Niño–Southern Oscillation (ENSO). El Niño weakens the trade winds and alters global weather patterns. In India, it often causes weaker monsoon rainfall, droughts, and reduced agricultural production. Other regions may experience floods, storms, or heatwaves. Scientists monitor El Niño to improve weather forecasting and disaster preparedness. Understanding El Niño is essential for agriculture, water management, and climate studies worldwide.

2. La Niña

La Niña is the opposite phase of El Niño and is characterized by unusually cool sea surface temperatures in the central and eastern Pacific Ocean. During La Niña, trade winds become stronger than normal, increasing the upwelling of cold water. In India, La Niña generally strengthens the southwest monsoon and often brings above-average rainfall. Globally, it influences temperature, rainfall, hurricanes, floods, and drought patterns. La Niña is also a part of the ENSO cycle. Monitoring La Niña helps governments prepare for weather-related disasters and supports agriculture, fisheries, and water resource planning.

3. ENSO

ENSO (El Niño–Southern Oscillation) is a recurring climate system involving changes in sea surface temperatures and atmospheric pressure across the tropical Pacific Ocean. It has three phases: El Niño (warm phase), La Niña (cool phase), and Neutral. ENSO strongly influences global weather, including rainfall, droughts, floods, cyclones, and temperature patterns. In India, ENSO significantly affects the southwest monsoon, agriculture, and water availability. Scientists monitor ENSO using satellite observations and ocean buoys. Understanding ENSO improves climate prediction, disaster management, food security, and long-term environmental planning across the world.

4. Monsoon

A monsoon is a seasonal reversal of winds caused mainly by differential heating of land and sea. During summer, land heats faster than the ocean, creating low pressure over land that draws in moisture-laden winds from the sea, bringing heavy rainfall. In winter, the process reverses, and dry winds blow from land to sea. India experiences the Southwest Monsoon and Northeast Monsoon. Monsoons are vital for agriculture, drinking water, hydroelectric power, and ecosystems. Variations in monsoon intensity influence crop production, water resources, and the national economy.

5. Cyclone

A cyclone is a rapidly rotating low-pressure weather system with strong winds and heavy rainfall. Tropical cyclones develop over warm ocean waters where sea surface temperatures exceed about 26.5°C. Warm, moist air rises, creating low pressure that draws in more air, producing a spiraling storm. Cyclones can cause flooding, storm surges, coastal erosion, and widespread destruction. In the Indian Ocean, they are called cyclones, while similar storms are called hurricanes or typhoons elsewhere. Early warning systems, evacuation plans, and resilient infrastructure help reduce cyclone-related damage and protect human lives.

6. Anticyclone

An anticyclone is a high-pressure weather system where air sinks and spreads outward from the centre. Descending air suppresses cloud formation, resulting in clear skies, dry weather, and light winds. In the Northern Hemisphere, anticyclones rotate clockwise, while in the Southern Hemisphere, they rotate anticlockwise due to the Coriolis Force. Anticyclones are associated with stable atmospheric conditions and pleasant weather but may also cause fog and cold waves during winter. Meteorologists study anticyclones to understand weather forecasting, atmospheric circulation, and seasonal climate variations.

7. Biodiversity Hotspot