Meteorologist Krishna B Manandhar of Nepal's Department of Hydrology and Meteorology relies on experience and instincts honed over more than two decades to read the weather and make forecasts.
But assisting him in his analysis is data from around the world and American and Japanese satellite imagery. "Weather forecasting isn't like astronomy or guesswork. There's a lot of sophisticated technology involved," says Manandhar, who is head of the department's Meteorological Forecasting Division. "Contrary to what people think, we don't just look up at the skies and predict that it is going to be 'fair throughout the kingdom'." Meteorology has no geographical boundaries, and the technology Manandhar and his colleagues rely on is proof. They use a system called SADIS (Satellite Distribution System), which Nepal has had access to for almost three years. It provides weather reports and forecasts from the World Area Forecast Centre in London.
Specifically designed for aviation purposes, it details weather turbulence patterns, icing, jet stream winds, volcano eruptions, temperature, and air pressure up to about 15,200 m. In addition to SADIS, they also rely on AMSS, which is a two-way Automatic Message Switching System based on VSAT (Very Small Aperture Terminal) technology. The system is basically an information network, and allows the department to send out and receive weather reports and forecasts from around the world every half hour in the day and every hour at night, 365 days a year. Images captured by a geostationary meteorological satellite (at a height 36,000 km) and the American polar orbiting NOAA (National Oceanic and Atmospheric Administration) satellite (at 1,300 km) further help in observing weather patterns, trends and phenomena. The final, comprehensive weather charts are drawn manually based on all this information.
"We're not exactly using cutting-edge technology but considering the equipment, the manpower, and resources available, we attain 70-75 percent accuracy in forecasting," says Manandhar. That's not too bad. Meteorological services departments aim for one hundred percent accuracy, but that goal is never reached. Even the most sophisticated equipment and technology assures at best 85-90 percent accuracy. Nepal's meteorological forecasting division provides weather reports and forecasts primarily for flight safety and flight operation purposes and mountaineering expeditions, and morning and night reports for the public.
Getting it right. Or not
Spread out before Manandhar are weather maps extending to Mongolia in the north, the coast of China in the east, Israel in the west and Maldives to the south. In the last week of May, he was following the growth of a cyclone that originated as a low pressure point in the Arabian Ocean, and within a few days turned into a severe cyclone that threatened the Gujarat coastline but later weakened rapidly. A survey of such intense and early pre-monsoon activity in the Bay of Bengal and the Arabian Sea enabled forecasters to predict that the monsoon would arrive around 7 June.
Due to its geographic location Nepal is relatively safe from cyclones that can cause devastating damage in coastal countries like Bangladesh where they are an annual feature and, as in the early 70s, can kill over 100,000 people from resultant flooding and building collapse. But Kathmandu Valley does see pretty strong winds-up to 108 kmph-in the local storms that hit us March through May. And the aftermath of a major cyclone, which can generate winds up to 200 kmph in the subcontinent (which even meteorological instruments cannot withstand) can result in unexpected rains and snowfall in the Himalaya, causing damage and loss of life. In 1995 more than 60 trekkers, mostly Japanese, died owing to unexpected rain and snow in November. At the time, weather forecasters had predicted that a cyclone originating in the Bay of Bengal would move in a northeasterly direction towards Assam. Instead, it moved north to Patna, with totally unexpected speed and intensity. "There were cloudless conditions all over Nepal the day before," recalls Manandhar.
Topographically, Nepal is a hard country to read-the high mountains and rugged terrain make it difficult to predict how weather patterns in the area will pan out here, so forecasting is something of an art. Meteorologists here say repeatedly that they need three-dimensional data, including altitude, to make accurate forecasts. So far only surface data is available. Radio sonde equipment-a weather balloon fitted with remote sensing technology that helps forecast thunderstorms and measure temperature, upper atmospheric pressure, wind and humidity up to around 150 km, was used for five years, between 1975-1980, but proved too expensive. The cost of running the equipment would today amount to over Rs 5 million annually. A weather radar would help, but the cost of a Doppler, the most sophisticated kind, is estimated at Rs 150 million, and we'd need trained manpower to operate it. China has three such radars, Thailand has two.
"Cost-wise, it's out of the question, but our accuracy would increase greatly and it would enable us to provide regular weather updates to the public every hour through FM radio," says Manandhar, whose division will soon be providing more detailed local forecasts on their website. The department has applied for assistance from the Japan International Cooperation Agency (JICA) to update their equipment. In the past experts from Israel, Sweden, the Czech Republic, and the US have helped the department. India could be a potential source of expert assistance-it has 150 years experience in meteorological services, compared to Nepal's 32. Nepal has been negotiating with India for two years to obtain INSAT facilities. INSAT would provide a closer, more detailed image of Nepal and the subcontinent. The present Japanese and American satellite images, which Nepal has been relying on for 20 years and will be phased out within the next couple of years, show the country as a tiny speck, which makes weather reading and forecasting difficult. "It [sharing INSAT facilities with Nepal] would be to India's advantage, too," says Manandhar. "We would be able to forecast floods in Nepal and Bihar."
Sky cover
The Meteorological Forecasting Division collects information from 15 synoptic stations, over 300 rain gauge stations, and 43 climatological stations around the country. A synoptic station makes surface weather observations at periodic times (usually at three-hourly and six-hourly intervals specified by the World Meteorological Organisation), of sky cover, the state of the sky, cloud height, atmospheric pressure reduced to sea level, temperature, dew point, wind speed and direction, amount of precipitation, hydrometeors and lithometeors, and special phenomena that prevail at the time of the observation or have been observed since the previous specified observation. The climatological stations gather data that helps in studying the processes of climate formation, the distribution of climates over the globe, analysis of the causes of differences in climate and the application of climatic data to the solution of specific problems. Their focus is more long term than the next weather report and they usually produce charts on the principal climatic elements of a specific region for a long period, say a few months or years. All the information is put to use in weather forecasting for agricultural and industrial purposes and lately for research in the environmental sector. Some of the data is exchanged globally through New Delhi.
"It is because our visual presentation is so bad that the public feels we don't know our job," say officials. "They tend to rely on the BBC and CNN which have much more attractive forecasts." But that doesn't mean these networks don't slip up at times, despite their sophisticated computer and digital technology and colourful, chatty presentations. "Sometimes they will report Kathmandu's maximum temperature at 35 degrees when it is actually 30 degrees," says Manandhar. "Because they use computers to read weather on a large scale map, Nepal gets lost. Here, we're manually analysing weather patterns on an area-specific map." Weather read closer to home generally makes for more accurate forecasts.
Manandhar reckons we're going to see some interesting weather in times to come. Don't roll your eyes at your septuagenarian friend-it is getting hotter every year-one degree per decade over the last couple of decades, says the Meteorological Forecasting Division.
