Do you recall any incident or a meeting where you or your friend refers to something like the birds chirping in a special way and predict that its gonna rain today? You do, right…
Well, everybody in India or for that matter in most parts of the world is a weather forecaster. Depending on strange facts like how did the cow sit down in the morning, to birds chirping, to some of his personal experiences, one comes out with one guess or another?
But in reality that’s not the scene. Weather forecasting is science. The science of weather forecasting is ancient. Even the age old mythological and classic literatures talk about Weather forecast. Kalidasa’s Meghdoot has mentions of weather forecasts, and even weatherman earlier were dependent on their experiences about the appearances of clouds or animal movements. I do it quite often even today; I go out every morning as I wake up and look at the sky to get an idea of the day’s outlook. Also at times I can co-relate some changes in my body and associate that with weather change.
But these are some vague examples, and we all know that there is a lot to be done for weather forecasting. We must understand the great amount of work put in by the weather scientists in this regards. In India, the Indian Meteorological Department (IMD) faces a lot of constraints too when it comes to predicting.
There were times when the scientist had to depend on a land based instruments and by using their knowledge and experience, the experts make daily forecasts. These forecasts about extreme weather situations like floods, cyclone, and even rainfalls used to fell short. For example, the forecast about the 1999 super cyclone which was one of the most destructive in current times claiming more than 10,000 lives, in time and with accuracy could have saved many precious lives.
But the scenario is changing today, with the aid of a fleet of satellites and advanced analytical systems, scientists are now able to predict accurately about the occurrence of various weather and natural phenomena. E.g., the forecast about cyclone Phallin that hit Odisha and Andhra Pradesh in 2013 and Hudhud that destroyed Visakhapatnam in 2014, or the Chennai floods of 2015; each is a testament of their achievements.
All these forecasts made by scientists at IMD were backed by a well-organised disaster management system. Today almost everybody whether he is a normal city dweller or a farmer or a fisherman or a tourist looks up to the weather data issued by IMD before planning his next few days schedule.
Is this data fully correct, “No, never” says M Mohapatra, Director General, National Weather Forecasting Center. He further informs us that “Weather is a non linear system, hence forecasting exact weather is impossible. With the improved technology, latest equipment and utilizing best of scientific brains, the only chance is to make fewer errors.”
With changing lifestyle and modern day necessities, we need close to accurate authentic forecasts. “One has to understand here that the weather has no boundaries, and data for the whole globe has to be used for predictions. We cant predict weather for one particular place without studying the atmospheric phenomenon of the whole globe” M Mohapatra further informed us.
Weather predictions date back to the British era in India. Before that it was all through word of mouth or by personal experiences and feelings. It started in the late 19th century when many of the British ships were washed away because of cyclones.
In earlier years when there were no proper equipment to take an image of the whole globe, so images were collected on a time based system. Every three hours one observation was recorded and the based on the readings from these images covering the whole globe (correlated with different pictures from different parts of the world), scientists made predictions of the weather. But this system, called the Synaptic Observation based on simultaneous observations was not fully accurate. It was good for a very short period of time, say 3-4 hours, and again for the next period or day there has to be another observation.
Then a system called Climatology was used which predicted weather based on an average of 30 years of world’s weather data. We then used climatology along with synaptic observations and data was predicted through a method called Synaptic Climatology.
But all these were methods based on static observations, and a dynamic approach was required to correctly predict the weather. So through a concept called the Dynamic meteorology, using mathematical equations with the atmospheric movements and various kind of forces acting in nature and solving these situations, weather predictions were made.
M Mahaptra further added that weather forecast is nothing but the Observations made after examining and understanding the environment changes and constant experiments going on in the atmosphere. He added that you cant have 100% accuracy, but with proper observations one can reduce the error. Hence a forecast is always an evaluation on the basis of errors. The less the error – the more the accuracy, and over the years the error is decreasing and this is a good sign.
The environment is a combination of physical, chemical and biological processes – all at one time. And we need to understand the impacts to do the forecast. Experiments get conducted at every moment in the atmospher, and all the by-products are seen in the form of rain, storms, thunder or even hail storms. We have to understand this through numerical models. Once the information is received from the satellite, scientists analyse them and then circulate the data to State Meteorological Centers, who in turn compile the data and send them across to regional centers. And the complete information is disseminated to the last mile within half an hour or even less.
The forecast for this year’s summer for India is this that it will be a much hotter than normal summer, and we already are experiencing that in the month of April only with temperatures already over 44. People are now prepared accordingly, but was this the case in earlier years too? No, No, till 1999, no one believed the Mausam forescast as it used to come on TV news or Print media.
It used to be the reverse of what was predicted most of the times. There used to be two forecasts every day – morning and evening. But today things have changed. M Mahapatra said that the failure of 1999 Cyclone forecast was not a science failure; it was the lagging behind on the technological front that failed us. “How can you expect us to compete with developed countries without having proper infrastructure? Where were we in terms of modern Technology? The Tsunami of 2004 was the turning point but it was only after 2006 that the govt. got moving. It was the year when institutions including IMD (earlier known as Directorate General of Observatory), NCMRWF and IITM Pune came together with the dept of Ocean Development and a new ministry was formed – the Ministry of Earth Sciences. It was a wise decision because if you talk about weather and climatic services, you cannot talk only about atmosphere. Ocean is an important component of the climate system and plays an important role in weather forecasting, added an IMD official.
Till 2006 IMD receieved three hourly observations from satellite Kalpana, but now the observations ome in half hourly inputs from three satellites, Kalpana 1, INSAT 3A, and INSAT 3D. Apart from this the radar technology has also improved – from 4 Doppler Weather Radars in 2006 to 24. The models used also have changed; before 2006 limited model area with 110 km resolution was used, whereas today they use 3 different types of Numerical Weather Prediction Models.
Long forecasting of monsoon season rainfalls also has shown significant improvement in the last decade. IMD successfully predicted the deficient rainfall for 2015.
The basic thing to improve in weather forecast is to enhance its observation capacity. Hence in the modernization programme, IMD did a lot of investment in its observation systems, for instance, surface observations, upper air observations, deploying radar and Doppler Weather Radar Network. Another helpful factor in forecasting is to instantaneously communicate large volume of data which is generated. Therefore IMD has also taken steps to modernize its telecommunication network to fetch process and assimilate it into numerical models.
Due to the modernisation programme of IMD there has been significant improvement in weather forecasting; the short and medium range forecasts have increased from 48 hours in 2006 to 120 hours in 2016. There has been a 41 percent decrease in false alarms and 33 percent in missing rate for rainfall in recent years. Post 2014 extremely short term weather forecasts for thunder and hail storms are available three hourly in 180 cities within the range of Dopppler Weather Radars. Among other improvements, local forecast which was earlier limited to the state capitals, is now available in 340 small ad big cities. Now there is extended range of forecasts issued once a week, predicting rainfall and temperature for the next four weeks.
Exact weather forecast has immensely helped various sectors including agriculture, fisheries, tourism and medical. All these sectors have different needs for weather information. For instance, a fisher man is never bothered about temperatures; all he wants to know is the wind movement while he is at the sea. Similarly a tourist makes plans to go to the hills or to the beach depending on the rains, etc.
The entire spectrum of modernization has helped IMD to improve the forecast skills, and hence the weather sensitive process. Be it agriculture aviation power health or transport sectors, the entire spectrum of economic activities have benefitted. Now farmers receive bi-weekly forecasts with a five day validity period and around 2 crore farmers receive SMS alerts on weather forecasts. These forecasts have also helped the country economically. According to IMD, statistics in 2010 showed that annual savings because of accurate meteorological information the annual savings were to the tune of 50000 crores. National Council for Applied Economic Research reported in 2015 that the profit attributable to the use of weather predictions by IMD is about 25 percent for different types of crops.
In the case of Hudhud cyclone, which lashed the eastern coast of India, IMD gave complete and advance warnings and also for Phallin in October 2015. Flood warning for the worst ever floods in Chennai was also issued by IMD well in time. These warnings issued through radio, emails, SMS, social networking sites, and Google alerts. These timely warnings saved many lives and also the losses. We saw less destruction as measures for protection were taken up well before the cyclones hit.
In the current year, IMD is well equipped with a promising future. The dept now has 552 observatories, 1350 gauges, 675 automatic weather stations, 24 radars, three satellites, and a work force team of 4000 people.
IMD today is better than Japan and at par with USA. IMD still lags behind USA only in terms of equipment. The advancement in telecommunication has helped to achieve the targets. In near future IMD plans to set up observatories in the Himalayan region too.