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Thursday, July 19, 2018

The Demistifier

When it comes to predicting the fog,Dr Jenamani knows best.

Written by Geeta Gupta | Published: January 1, 2012 1:00:03 am

Head of the North India Aviation Meteorological Services and the Met department at IGI Airport,Dr Rajendra K Jenamani’s expertise in real-time fog prediction makes him one of the most sought-after persons across North India at least during the months of December-February — rattling off fog predictions as if he were born with the knowledge.

These days,it is not just the airlines and airport operators who are the most bothered souls during foggy months. Several others,including politicians,corporate honchos and bureaucrats,keep 43-year-old Jenamani’s number on their phone’s speed dial list for the kind of expertise he has to offer in the field of fog monitoring and analysis. Many in the political sphere,ranging from the wife of a prominent Opposition leader to Samajwadi Party leader Mulayam Singh Yadav’s pilot,keep in constant touch with Jenamani for charting out their future plans.

There are also others who use this expertise in non-aviation sectors — the fog analysis and prediction report prepared by the IGI Met department is used by the Railways,Power Grid Corporation of India,National Highways Authority of India and Bangladesh’s Meghna River Ferry Service,among others.

While Jenamani believes the ideal situation would be accurate fog nowcasting for minute-by-minute analysis of the weather,he says the day they can achieve 99.9 per cent accuracy in fog forecasting is not a long way off. “The prediction accuracy,which was 75 per cent in 2008,has improved to 95 per cent now. This is called the ‘yes or no’ forecast on whether there will be dense fog. But the greatest challenge now is to predict the exact time of dense fog formation and that of its lifting,” Jenamani says.

During periods of severe fog,Jenamani starts his day with a briefing with DIAL,ATC and the airlines at 6.30 am — to spell out the scale of fog,local features and the time it is likely to turn shallow — so stakeholders can brace themselves for facing their respective challenges. Then he briefs the media,so that the information can reach everybody affected by it. “We are now the prime centre of fog forecasting and monitoring,with the expertise that this office has demonstrated since 2005,” he says.

Even though technological enhancements are on their way to make fog forecasting more accurate,one major task that covers for 50 per cent of the work is checking on the status of the runway visibility range (RVR).

The IGI Met department now has a weather analysis workstation,procured from MeteoFrance,where three-dimensional data of surface conditions over North India,Pakistan and Afghanistan is analysed. “It is important to analyse the winter weather conditions,such as western disturbances over Pakistan and Afghanistan,because winds originate there and move towards northern India and Delhi. So,reading western disturbances is a priority during winters,” Jenamani says.

He defines western disturbance as a cyclonic disturbance that carries moisture,which gets converted into rain and snow as it reaches North India,especially Jammu and Kashmir. “So scientifically,when a western disturbance approaches,the winds over North India become easterly,and the night temperature increases,” he explains. The cyclical pattern of the western disturbance brings with it all the ingredients essential for the formation of fog,he adds.

The formation and impact of fog at the IGI Airport,however,is a peculiar phenomenon because “it is not a homogeneous event due to the geographical location of its runways”. Runway 28,which is flanked on both sides by various structures such as the Metro station and the terminal building,experiences 30-50 per cent less fog when compared to Runway 29 — which is surrounded by an open area. The presence of Shiv Murti on NH-8 gives in for some variation also because a displacement of 1,400 metres has been maintained as the mandatory threshold for aircraft landing on Runway 29.

An essential requirement as per the International Civil Aviation Organisation (ICAO),Runway 29 had three RVR instruments when it was commissioned in 2008. “Two more RVR instruments have now been commissioned for Runway 29,so that the entire runway be utilised. This is,i guess,the first runway in the world to have as many as five RVR instruments. But that is because of the peculiar nature of fog formation here,which varies at different places along the same runway,” says Jenamani.

The challenge for Jenamani and his team is to bring about a runway-wise fog prediction system that would fill the gap in accuracy between prediction and communication. “We will soon tie up with a mobile service provider to start our SMS service. Through that,all subscribed users would be able to benefit from the latest forecast; even passengers would be able to subscribe to the service,” Jenamani says.

Apart from aviation,Railways is the second biggest sector affected by fog. “But they have no solution. Cancellations and delays increase costs and the poor people are affected,” he adds. Jenamani now wants to do a pilot project for the Railways to develop a RVR-type instrument,probably a visibility meter,on the Delhi-Ambala sector to find a mechanism for minimising the impact of fog on train services.

Hailing from Sarangapur in Orissa,Jenamani completed his masters in applied mathematics with fluid dynamics from Utkal University and relocated to Delhi in 1992 to pursue his doctorate. Even while he was doing his PhD at IIT Delhi,he cleared his UPSC exam and was offered a job with the Indian Meteorological Department in Pune. He joined its Delhi headquarters in 2002.

Jenamani won the Young Scientist Award in July 2007 for his contribution to weather forecasting,and setting up the fog prediction model at IGI airport.

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