Environment and Disaster Management › Climate science

Extreme weather, monsoon and forecasting

Weather and its extremes, the monsoon and the ocean patterns that drive it, heatwaves, cyclones, cloudbursts and lightning, and the forecasts and radars that meet them. Prelims has asked about the Finance Commission's recommendations on disaster funding.

Foundation note: Disasters: the notified calamities and the warning chain

cloudburst: Sudden very heavy rain, taken by the India Meteorological Department as more than 100 mm in an hour over a small area.

State Disaster Response Fund: The fund a State draws on for relief and reconstruction immediately after a notified disaster.

State Disaster Mitigation Fund: The fund for long term works that reduce disaster risk before a disaster, rather than relief after one.

Doppler shift: The shift in a wave's frequency when its source and observer move towards or away from each other; the radar reads it to find the wind inside a cloud.

weather modification: Deliberate intervention in the atmosphere, such as seeding clouds, to change how much rain falls.

Niño 3.4 region: The equatorial Pacific box whose sea surface temperature anomaly sets the ENSO phase.

Long period average: The average June to September rainfall over 1971 to 2020, 87 cm.

Southern Oscillation: The see saw of air pressure between the eastern and western Pacific.

Uncompensable heat stress: A condition in which the body cannot cool itself by sweating because of extreme heat and humidity.

Regional Meteorological Centre: The IMD office that coordinates weather and climate services for a group of States.

Moisture adequacy index: An index of soil moisture used in assessing drought.

Trigger-1: The first alert stage of Maharashtra's Drought Management Code, based on rainfall deficiency and a dry spell of at least 21 days.

Panchnama: A field survey that records the condition of a crop.

Kallakadal: The name fishermen in Kerala give to a swell surge.

Also filed elsewhere

Forest fires · on Forests, grasslands and mountain ecosystems
Forest fires in India are tracked through alerts that the Forest Survey of India (FSI) reads off satellite passes.
Heat Action Plans · on India's climate policy: NDCs, net zero and adaptation
Extreme heat is met city by city rather than nationally, which is at once the strength of the instrument and its limit.