WiFEX: Ten winters and countless hours of fieldwork unravels India's winter fog
Dr Ravichandran along with other officials visited the WiFEX and System for Air Quality and Forecasting Research (SAFAR) control room at the Indian
Institute of Tropical Meteorology (IITM) on Tuesday.
On the occasion a state-of-the-art atmospheric chemistry laboratory as inaugurated and the website of an Early Career Researchers' Hub for Earth
Sciences as also launched.
Dr Ravichandran later spoke to media persons about ho accurate forecasts under WiFEX have provided significant operational benefits to airlines including reductions in flight diversions and cancellations.
'Based on this success WiFEX is no progressing to its next phase WiFEX- II and these capabilities ill be expanded to major airports in North India so
the advanced instruments can better predict localised fog events at airport runways,' he said.
Led by the Indian Institute of Tropical Meteorology (IITM) under the Ministry of Earth Sciences (MoES), with support from the India Meteorological
Department (IMD) and the National Centre for Medium Range Weather Forecasting (NCMRWF), WiFEX is one of the world's fe long-term open- field experiments focused solely on fog — an elusive winter hazard that regularly disrupts air, rail, and road transport across the Indo-Gangetic Plain.
What began at IGIA — India's busiest and most fog-affected airport — has grown into a robust observational network now reaching Jewar Airport, Noida, and Hisar, Haryana, covering key aviation corridors across North India. Over the past decade, WiFEX scientists have deployed advanced instruments, micrometeorology towers, ceilometers, and high-frequency sensors to collect detailed data on temperature layers, humidity, wind, turbulence, soil heat, and aerosols — building an unmatched dataset that reveals ho dense fog forms and disperses.
'These insights have powered the development of a high-resolution (3 km) probabilistic fog prediction model, which no stands among the region's most advanced tools for operational forecasting. This model can reliably predict hen fog will begin, ho dense it will be, how long it will last, and when it will clear — achieving more than 85% accuracy for very dense fog (visibility below 200 metres),' Dr. Sachin Ghude, Project Director, WiFEX and SAFAR explained.
WiFEX is stepping into its next phase — WiFEX-II — which will extend localised, runway-specific fog predictions to more airports in North India. By in stalling dedicated sensors at additional sites, airport operators will gain real-time data to help them activate response plans and ensure operations remain
safe and efficient — even in the thickest fog. 'After ten winters and countless hours of fieldwork, WiFEX is shining example of hat sustained, focused re-
search and collaboration can achieve. By connecting observations to models and models to real-world decisions, WiFEX proves that science can clear the path forward,'Dr Suryachandra Rao, Director , IITM added.
'By this November Wi-FEX-2 will be launched at Noida, Jaipur, Varanasi and plans are underway for introducing the systems at Guwahati,' Dr Ghude said. IITM scientists explained that for airlines, pilots, air traffic controllers, and passengers, this means fewer costly diversions, fewer delays, safer runways, and more informed travel during the challenging winter fog season.
'We also need to reduce false alarms and the WiFEX -2 will help us address this pertinent issue,' Dr Ghude added.
Meanwhile, at forward locations, the Indian Armed Forces have expressed a need for similar fog prediction solutions, IITMexperts said. They pointed out that while sophisticated instruments are available at IGI Airport in New Delhi, the accuracy of predictions at the requested locations depends on the availability of local weather and cloud data.
On the NISAR satellite
Dr M Ravichandran, responding to queries on the NISAR satellite – jointly developed by NASA and ISRO and scheduled for launch soon said that they would wait for data.
The NISAR satellite will examine water bodies, forest loss and so on. He also said that they were collaborating with ISRO to request the launch of a new
satellite. —INSAT-3DS is a dedicated meteorological satellite launched by ISRO to enhance weather forecasting and disaster warning capabilities.
According to the expert as part of their transition to the fourth-generation series, preparatory work is underway. 'On August 23, we will outline and prioritise our satellite data requirements for weather monitoring. Each sector will be formally informed about these priorities and their
relevance,' he said.
Anuradha Mascarenhas is a journalist with The Indian Express and is based in Pune. A senior editor, Anuradha writes on health, research developments in the field of science and environment and takes keen interest in covering women's issues. With a career spanning over 25 years, Anuradha has also led teams and often coordinated the edition.
... Read More
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Hindustan Times
13 hours ago
- Hindustan Times
400 frontline forest staff identified for zoonotic disease screening
PUNE: In a bid to enhance early detection and raise awareness about zoonotic diseases, nearly 400 forest and zoo staff members in Maharashtra have been shortlisted for medical screening. Registration for the screening process will begin soon, followed by a series of medical tests. The initiative aims to safeguard both wildlife and human populations by identifying potential risks of disease transmission among individuals most frequently in contact with animals. In a bid to enhance early detection and raise awareness about zoonotic diseases, nearly 400 forest and zoo staff members in Maharashtra have been shortlisted. ((PIC FOR REPRESENTATION)) Launched in January of this year, the program titled 'Building a Surveillance Model for Detecting Zoonotic Spillover in Increased Bird-Human Interaction Settings' adopts the one Health approach, a concept recognising the interconnection between people, animals, plants, and their shared environment. This pioneering project is a joint effort by the Maharashtra Forest Department, the Indian Council of Medical Research (ICMR), the National Institute of Virology (NIV), Pune, and Symbiosis International University. The program focuses on developing a real-time surveillance model to monitor zoonotic spillovers among frontline forest staff, zoo workers, bird sanctuary staff, and residents living near wetlands. Zoonotic diseases—those transmitted from animals to humans—are emerging as a significant global health threat. Notable examples include the Nipah virus, Ebola, Zika, SARS-CoV-2, Avian Influenza Virus (AIV), and Monkeypox. Despite the growing threat of zoonotic infections in India, scientists have noted a lack of comprehensive data on such diseases within the country. Since its launch, several awareness and sensitisation programs have already been conducted in districts such as Satara, Ahilyanagar, Solapur, and Junnar. Dr Satish Pande, a conservationist and researcher leading the sensitisation program, shared that the response to the initiative has been overwhelmingly positive. Following the sensitisation sessions, many frontline workers expressed eagerness to enrol. To date, 400 staff members have been identified for enrollment, with the registration process still ongoing. Once registration is complete, participants will undergo medical check-ups, including blood tests, to assess if they have been exposed to any viral infections via the presence of antibodies. Following the initial assessments, the health of each participant will be monitored over the next three years. In Maharashtra, four wild animals—including three tigers and one leopard—have died this year due to Avian influenza. Across India, at least three human deaths linked to zoonotic diseases have been reported. These cases highlight the increasing concern over zoonotic infections, particularly as viruses continue to breach species barriers. Frontline workers, who have frequent contact with both animals and local communities, are emerging as a potential link in the transmission chain. Dr Pande emphasised that this program will provide close health monitoring for these key personnel, making a significant contribution to both wildlife conservation and public health safety.
India Today
13 hours ago
- India Today
Nisar: The billion-dollar radar that can see through clouds and darkness
When Nisar, a.k.a the Nasa-Isro Synthetic Aperture Radar, takes flight aboard India's GSLV Mk-II rocket from the Satish Dhawan Space Centre, Sriharikota, on July 30, 2025, it won't just be another Earth observation satellite in orbit, it will be a technological marvel, the likes of which the world has never seen satellite will be placed in a sun-synchronous polar orbit, 747 km above Earth, completing 14 orbits every just 97 minutes, Nisar will circle the planet once, and in 12 days, it will have mapped nearly every inch of Earth's landmass and ice sheets. For scientists, climate researchers, and disaster managers, this is a dream come true. The mission's open-source data will be freely available to researchers. (Photo: Isro) WHAT MAKES NISAR A GAME-CHANGER? At its heart, Nisar carries a world-first technology – a dual-frequency Synthetic Aperture Radar (SAR). Most radar imaging satellites work with a single frequency, but Nisar carries two powerful radar systems: L-band radar (24 cm wavelength) built by Nasa and S-band radar (12 cm wavelength) developed by unique combination allows Nisar to 'see' through clouds, thick forest canopies, smoke, and even in complete importantly, it can detect tiny changes in the Earth's surface, as small as a few millimeters. That means scientists can track how much a glacier has shifted, how much a fault line has moved after an earthquake, or even how much a city is sinking due to groundwater depletion. Nisar is set to become something more – a guardian that can sense Earth's heartbeat. (Photo: Nasa) Nisar achieves this precision through a special technique called Interferometric Synthetic Aperture Radar (InSAR). Think of it like taking two radar 'photos' of the same place a few days apart and comparing them to spot tiny sends out invisible radar waves to Earth's surface and listens for the waves that bounce back. By carefully analysing the timing (or 'phase') of these returning waves, InSAR can detect changes as small as a centimeter, like the ground shifting slightly after an earthquake or a glacier moving over creates detailed maps showing how Earth's surface is changing, helping scientists predict disasters or monitor climate shifts with incredible accuracy, no matter the weather or time of this data is made possible thanks to its massive 12-meter gold-plated deployable mesh antenna – the largest radar imaging antenna ever launched into space. For comparison, it's almost as wide as a badminton court when fully unfolded. WHY THE WORLD NEEDS NISAREarth's rapid changes are outpacing the capabilities of traditional satellites, which often lack the precision needed to capture critical details. Nisar bridges this gap with its high-resolution, all-weather, day-and-night imaging, delivering a near real-time view of our planet's dynamic will revolutionise our understanding by:advertisementTracking climate change: Observing polar ice loss, glacier shifts, and permafrost thawing with unprecedented management: Identifying subtle signs of land subsidence, landslide risks, and fault-line movements to predict earthquakes & water security: Forecasting crop yields, monitoring soil moisture, and mapping groundwater depletion to ensure resource & ecosystems: Measuring deforestation, forest biomass, and the carbon storage potential of vegetation to support conservation simple terms, Nisar will give us a near-real-time 'health check-up' of the Earth every few days. It has the largest radar imaging antenna ever launched into space. (Photo: Nasa) A BILLION-DOLLAR PARTNERSHIPNisar is one of the most expensive Earth observation missions ever undertaken, with a total cost estimated at $1.5 billion (Rs 12,500 crore).Nasa's contribution, covering the L-band radar, radar electronics, GPS receivers, and engineering support, is approximately $1.2 billion (Rs 10,000 crore).Isro's contribution, which includes the S-band radar, satellite bus, launch vehicle, and ground systems, is around Rs 788 crore (approximately $93 million).Despite the significant investment, the mission's open-source data will be freely available to researchers and governments worldwide, offering immense value for global scientific and climate research efforts. THE ROAD AHEADFor decades, satellites have been our eyes in the sky, but Nisar is set to become something more – a guardian that can sense Earth's tracking movements invisible to the naked eye, it promises to help humanity understand natural hazards, prepare for disasters, and fight climate it finally unfurls its giant golden antenna in orbit, Nisar will mark not just a triumph of space technology but also a symbol of international cooperation for the planet's future.(This is an authored article by Manish Purohit. Manish is a solar energy and spacecraft solar panel expert with extensive experience in managing critical space missions, including Chandrayaan-2 and Mangalyaan)- EndsMust Watch
The Hindu
18 hours ago
- The Hindu
What makes the NASA-ISRO NISAR satellite so special?
The story so far: The Indian Space Research Organisation (ISRO) is planning to launch the NISAR satellite from Sriharikota on July 30 onboard a GSLV Mk-II rocket. 'NISAR' stands for NASA-ISRO Synthetic Aperture Radar and is a joint mission of the two space agencies. It is a sophisticated earth-observation satellite designed to study changes on the earth's surface in fine detail, covering earthquakes, volcanoes, ecosystems, ice sheets, farmland, floods, and landslides. What's the need for NISAR? NISAR is the first major earth-observing mission with a dual-band radar, which will allow it to observe changes more precisely than any other satellite. It will be able to see through clouds, smoke, and even thick vegetation, both at day and night, in all weather conditions. The three-tonne machine has been a decade in the making and costs more than $1.5 billion, also making it one of the most expensive earth-observing satellites to date. The earth's surface is constantly changing. Natural disasters, human-driven changes, and climate shifts all affect environments and human societies. Satellites provide critical information by taking snapshots of these changes from space, helping scientists, governments, and relief agencies prepare for, respond to or study them. To this end, NASA and ISRO have created a powerful global mission that also allows ISRO guaranteed access to a stream of high‑resolution data tailored to India's needs. NISAR's science and application goals span six areas: solid earth processes, ecosystems, ice dynamics, coastal and ocean processes, disaster response, and additional applications (including tracking groundwater, oil reservoirs, and infrastructure like levees, dams, and roads for subsidence or deformation and supporting food security research). The planned mission lifetime is three years although its design lifetime is at least five years. Notably, the mission's data policy entails that the data NISAR produces will be freely available to all users (typically) within a few hours. How does NISAR work? Once it is launched, NISAR will enter into a sun-synchronous polar orbit at 747 km altitude and an inclination of 98.4°. From here, instead of snapping pictures, NISAR's synthetic aperture radar (SAR) will bounce radar waves off the planet's surface and measure how long the signal takes to come back and how its phase changes. The ability of a radar antenna to resolve smaller details increases with its length, called its aperture. In orbit, deploying an antenna hundreds of metres long is impractical. SAR gets around this by mimicking a giant antenna. As the spacecraft moves forward, it transmits a train of radar pulses and records the echoes. Later, a computer coherently combines all those echoes as if they had been captured simultaneously by one very long antenna, hence the 'synthetic aperture'. NISAR will combine an L-band SAR (1.257 GHz), which uses longer-wavelength radiowaves to track changes under thick forests and soil and deformations on the ground, and an S-band SAR (3.2 GHz), which uses shorter-wavelength radiowaves to capture surface details, such as crops and water surfaces. Although NISAR will operate globally at L‑band, ISRO has reserved routine, planned acquisitions with the S‑band SAR over India. The latter acquisitions have extended sensitivity to biomass, better soil‑moisture retrieval, and mitigate ionospheric noise — all capabilities tuned to India's needs in agriculture, forestry, and disaster management. Because the L‑band radar is the principal tool for NASA's mission goals, the instrument is expected to operate in up to 70% of every orbit. This said, operating both radars together is an official implementation goal so that mode conflicts over the Indian subcontinent are minimised. Polarisation is the direction in which the electric field of some electromagnetic radiation, like radiowaves, oscillates. SAR can transmit and receive radar signals with horizontal or vertical polarisation. Using different combinations will allow the instruments to identify the structure and types of different surface materials, like soil, snow, crop or wood. The swath width, i.e. the breadth of the bands on the ground the SARs will scan, is an ultra-wide 240 km. The radars' SweepSAR design will transmit this beam and, upon its return, digitally steer multiple small sub‑apertures in sequence, synthesising beams that sweep across the ground track. This scan‑on‑receive method allows the 240‑km swath without compromising resolution. The resulting scans will have a spatial resolution of 3-10 m and centrimetre-scale vertical mapping — enough to spot impending land subsidence in cities, for example — depending on the mode. Each spot on the ground will be scanned once every 12 satellite also features a large 12-m-wide mesh antenna. NISAR will produce annual maps of aboveground woody biomass of 1 ha resolution and quarterly maps of active and inactive cropland. High-resolution maps of flooded versus dry areas will be available as well. During a disaster, NISAR can also be directed to collect data for 'damage proxy maps' to be delivered in under five hours. This said, for certain acquisition modes, NISAR won't be able to achieve full global coverage at the highest resolution. Above roughly 60° latitude, every alternative observation will be skipped due to converging ground tracks. Similarly, some 10% of the surface may not be mapped from either direction (of the satellite's passage over the ground) in any given 12-day cycle. How was NISAR built? At the time the two space organisations agreed to build NISAR, NASA and ISRO decided each body would contribute equivalent‑scale hardware, expertise, and funding. ISRO's contributions in particular are mission‑critical. The organisation supplied the I‑3K spacecraft bus, the platform that houses the controls to handle command and data, propulsion, and attitude, plus 4 kW of solar power. The same package also included the entire S‑band radar electronics, a high‑rate Ka‑band telecom subsystem, and a gimballed high‑gain antenna. The S‑band electronics were designed and built at the Space Applications Centre in Ahmedabad. NASA's biggest contribution was the complete L‑band SAR system. NASA's Jet Propulsion Laboratory supplied all radio‑frequency electronics, the 12‑m antenna, a 9-m carbon-composite boom, and the instrument structure that carries both radars. The agency also fabricated the L‑band feed aperture and provided the supporting avionics, including a high‑capacity solid‑state recorder, a GPS receiver, an autonomous payload data system, and a Ka‑band payload communications subsystem. The spacecraft was to be integrated at the ISRO Satellite Centre in Bengaluru after the two radars were mated at JPL. The final observatory‑level tests will therefore have taken place on Indian soil. After that the mission will lift off from Sriharikota onboard a GSLV Mk-II launch vehicle, with ISRO providing end‑to‑end launch services and documentation. While themission operations are to be centred at the JPL Mission Operations Center, day‑to‑day flight operations will be led from the ISRO Telemetry, Tracking and Command Network in Bengaluru. Once NISAR is in orbit, most of its data will be sent through NASA's Near Earth Network facilities in Alaska, Svalbard (Norway), and Punta Arenas (Chile), which can together receive around 3 TB of radar data per day. They will be complemented by ISRO's ground stations in Shadnagar and Antarctica. After the raw data arrive, India's National Remote Sensing Centre will process and distribute all products required for Indian users, mirroring NASA's pipeline.
