In News:

The Winter Fog Experiment (WiFEX) has completed ten successful years since its launch in 2015. Initiated at the Indira Gandhi International Airport (IGIA), New Delhi, WiFEX has emerged as a pioneering long-term scientific initiative aimed at understanding and mitigating the impact of dense winter fog over the Indo-Gangetic Plain (IGP) — one of the most fog-prone regions in the world.

What is WiFEX?

• Launched in Winter 2015 at IGIA, New Delhi.
• Led by the Indian Institute of Tropical Meteorology (IITM) under the Ministry of Earth Sciences (MoES).
• Supported by:
  • India Meteorological Department (IMD)
  • National Centre for Medium Range Weather Forecasting (NCMRWF).
• One of the world’s few open-field long-term experiments exclusively dedicated to studying winter fog.

Objectives of WiFEX

• To develop accurate now-casting (up to 6 hours) and forecasting systems for fog events over North India.
• To reduce the adverse impact of fog on:
  • Aviation (flight delays, diversions, safety).
  • Surface transport (road and rail accidents).
  • Economy and public safety.

How it was Conducted

Observational Framework

WiFEX deployed cutting-edge scientific equipment, including:

• Micrometeorology towers
• Ceilometers
• High-frequency sensors
• Radiometers
• Wind profilers

These were installed at multiple locations including:

• IGIA, Delhi
• Jewar Airport, Noida
• Hisar, Haryana

Key Parameters Studied

• Atmospheric temperature stratification
• Relative humidity and soil heat flux
• Wind speed and turbulence
• Aerosol concentration
• Urban heat island effects
• Land-use changes

This comprehensive data helped scientists decode how dense fog forms, persists, and disperses.

Major Achievements of WiFEX

High-Resolution Forecasting Model

• A 3-km resolution probabilistic fog prediction model was developed.
• Achieved over 85% accuracy in forecasting very dense fog (visibility <200 meters).
• Provides insights on:
  • Onset and dissipation timing
  • Fog density
  • Duration of fog events

Operational Impact

• Significantly reduced flight diversions and delays at IGIA.
• Enhanced airport safety and efficiency in fog conditions.
• Helped airlines and transport authorities activate timely contingency plans.

Scientific Contributions

• Showcased how air pollution, aerosols, urbanization, and land-use changes influence fog behavior.
• Facilitated improvements in early warning systems for North India.
• Informed urban planning and air quality policies for fog-prone areas.