Scientists set to launch fog forecasting experiment

Weather scientists are set to launch an experiment to collect data on fog in the Indo-Gangetic plains for developing a forecasting model to inform airlines and railways about the intensity and duration of the fog at least 24 hours in advance. “We will launch the project on December 6 and collect   data for two months to check the validity of our model and improve our forecasting,” M Rajeevan, secretary, Ministry of Earth Sciences told DH.

Almost 30 instruments have been installed at the Indira Gandhi International Airport to gather data to study fog microphysics. Once developed, the forecasting model will aid airlines and railways by alerting them about the upcoming fog scenario a day in advance. “Currently we can only say a fog may be coming but have no means to foretell its intensity and duration. The aim is to have an operational fog forecast,” said Rajeevan, one of the team members for the winter fog experiment.

“During the past 10-15 years, an increase has been observed in the frequency and intensity of fog occurrences over north India. The maximum fog occurrence over northwest India is about 48 days (when the visibility is less than 1,000 mt) per year and occurs mostly during the December-February time period,” said IITM scientist Sachin Ghude.

Thick fog in the plains of Uttar Pradesh and Bihar led to hours of delay and cancellation of many trains, including the Rajdhani Express, in the last few days. On Sunday morning, railway officials said 57 trains to Delhi were delayed while 11 trains had been cancelled. An envelope of fog disrupted the flight schedule too.

“Such a situation can be avoided with fog forecasting but cloud microphysics at a lower level needs to be understood better. We will create a vertical profile up to an altitude of 10 mt to study the complete environmental conditions in which fog develops,” Rajeevan said.

Instruments have been put in place to measure surface micro meteorological conditions, radiation balance, turbulence, thermo-dynamical structure of the surface layer, fog droplet and aerosol microphysics, aerosol optical properties, real time sky images, and aerosol and fog water chemistry. Researchers from the Indian Institute of Tropical Meteorology, Pune; Indian Institute of Science, Bangalore; Indian Meteorological Department, Delhi; Indian Institute of Science, Education and Research, Mohali; Indian Agricultural Research Institute, Delhi and the Savitrivai Phule Pune University have joined hands for the experiment.