Met Dept gears for perfect forecast

By Ranil WIJAYAPALA

The increasing number of deaths due to lightning which destroys vital equipment worth millions of rupees and displacement of people due to floods are issues that concern people and caused by changing weather patterns. An accurate weather forecast is vital for people to engage in their day-to-day activities and minimise the damage caused due to adverse weather conditions.

But the question is whether we get accurate weather forecasts to plan activities, for fishermen to engage in their occupation, contractors to plan development projects and farmers to cultivate at the correct time.

"Now we are living in a busy world and everything is becoming weather-sensitive. You can't wait anymore for things to happen. You have to be prepared. Everything is proactive and it is no longer reactive, because we are time-pressed and weather is becoming sensitive to the lives of the people. We need accurate forecasting", Meteorological Department, Director General, G.B. Samarasinghe said.

"As the World Meteorological Organisation says if you invest on sound weather forecasting equipment you will benefit. Therefore, we need to invest on good weather forecasting equipment if we rely on the weather forecast," he added.

According to Samarasinghe this year so far 48 deaths have occurred due to lightning and this is the highest number of deaths reported after 1997. This number of deaths has been 47.

"For a 20 million population this is a high rate and we need to address the issue as the damage to life and property could be enormous", he added.

He said the Meteorological Department is gearing up with its processes to improve the weather forecast and Research Unit to provide Weather Forecast for cities and various segments of people such as fishermen, industrialists and cultivators.

"We are training people for this task. I have formed a group for that and we can go for a three-day forecast of cities at ten stations. We might get it into another 12 or 20 stations.

This is a major challenge but we have to do it because people need accurate forecast", he added.

He says the Meteorological Department is achieving that task

by acquiring equipment with the support of international organisations and friendly nations.

"But equipment alone is not sufficient. There are many factors preventing us from giving accurate weather forecasting," he added.

The most important thing is the commitment of the people.

If people are not committed there is no use. "It is not a problem of equipment. Having equipment alone does not mean that you can forecast the weather properly", he added.

"For this we have to have an idea of how nature behaves. If we know that you can give an accurate forecast. If you do not know the atmospheric processes, that governs the weather you can't forecast it," he said.

We need data to predict weather conditions. For that you have to have upto date atmospheric information" he said.

Everything that happens at one end of the country or in the continent has an impact on local weather conditions.

"So the Department has to gather information about the situation everywhere and for that we have to have equipment," he added.

In Sri Lanka we have weather stations and conventional ones and they collect data from all the stations to forecast the weather for another six hours or for tomorrow.

"You need mathematical formula for that. Computer facilities are needed", he said.

If we have data and the know -how, the system works and the present condition in the atmosphere, then we can make a reasonable forecast. There is no equipment to obtain data vital to make an accurate forecast. "For meteorologists, their laboratory is the 'atmosphere' So that is the greatest disadvantage meteorologists have. While the system is going on we have to understand that.

"In European countries the weather forecast is very good because they have the information, they have a good weather system. So they can make a forecast because the systems are identified. In case of heavy rainfall, heavy snowfall or maybe high temperature they are successful in forecasting the weather.

Like last year in Switzerland they predicted heavy snowfall but not the exact figures," Samarasinghe says.

"In forecasting day-to-day weather, they can be confident because they have weather data they have an understanding of how it behaves. But catching the abnormality is not that easy because man-made interference with the system has made weather forecasting difficult" he added. "With industrialisation, greenhouse gases are being emitted to the environment. Man made effects have changed the set up. Those are the factors as to why we can't give a very good weather forecast. Day to day forecasting is possible if we know the physics behind this. But extended weather forecast is very difficult because of climate changes," he added.

But here in Sri Lanka we still have not identified the behaviour of the atmosphere well. Due to changes in the topography. In India too topography within the country is very different. One part is a terrain and the other is flat.

"When we take Sri Lanka one difficulty we have is the variety of geographical features different from place to place. So that makes it difficult to give a very good weather forecast", he added.

The other fact is that weather systems are micro scale. We have different weather patterns like large scale, medium scale, small micro and meso scale. Most of the features are meso scale.

"We don't have enough information, and the geographical features have blocked us from giving good forecast. We can give a forecast for Colombo and it should be different from Nuwara Eliya," he added.

"But when you log onto the internet they can give the weather forecast even for Karandeniya for instance. Sometime they give forecast for Haputale also. What they do is they get the Met Department data for Nuwara Eliya and Bandarawela and they are making interpolation or extrapolation of the information and make models and give a forecast. But that is not correct", he added.

"What we are lacking is we don't have models. Numerical model outputs or forecast models. When we give input here the out put is the six hours weather forecast. Temperature, wind speed, how much of rainfall during the past hours. For that we need to have a mathematical models describing all the physics in that part," Samarasinghe added.

For the whole world there are global models. When it comes to regions each region has different model and Sri Lanka can get a portion of that.

"So we are somewhat better because we have a regional model. That regional model has to be downscaled to the local level. For Sri Lanka we have to downscale that model into a small box like area in Sri Lanka. Every five degree information is there. For Sri Lanka we have only two grid cells. But in Sri Lanka have different weather patterns in various part of the country. To give forecast for these areas we need a finer scaled models.

"So we need computer facilities and very good know how of the science or the models and good models downscaled to the Sri Lankan scenario," Samarasinghe added.

Apart from this Sri Lanka's location in the tropical zone has also made it difficult to give a proper weather forecast. "Sometimes back it was said that tropical weather is easy to forecast the weather. But now they say that tropical weather is difficult for weather forecasting as Tropic is the place where we get the most sun light", he added.

For forecasting we need Doppler weather radars. Weather radars sensing the clouds and the atmosphere. So they are very useful in the short term weather forecasting.

"The system is already in Sri Lanka and construction work is in progress in Gongala. We will cover most parts of the country. We can't cover the entire country with one single radar. There is another place in Matale and we will have another one there soon", he added.

Apart from that the Department is also planning to set up a weather station at Pottuvil as an upper rear weather station. When there is upper rear station cyclone, and depressions forming in the bay of Bengal it can be detected.

"Not only that we have good coverage of stations in the country. We have to have many station representing each district. That is our plan", Samarasinghe added.

Apart from this installing a lightning detecting system is very very important.

"This year so far 48 deaths have occurred due to lightning. In 1997 the number of deaths due to lightning was 47. We have to think of that and we have to take care of that situation We get lot of equipment damaged due to lightning. So we have to be prepared and lightning detecting system is also in the cards and we will get it soon", he added.

"We need to have lightning detection system to cover the entire island may be with four or six sensors depending on the system they are employing and every centre is sending information to a central station so that people can shut down station if there is a big lightening", he added.

"We need these equipments because it will be much easier if we can have perfect forecast and people have a very good lead time to prepare for that. The value of weather forecast cannot be underestimated", he added.

"When all these things are there we can have perfect forecast as the output. We have to make it deliverable or customized to the peoples need. Fishermen should get some sort of a program and agriculture people should get another forecast day-to-day public get another one industrials get another one. We must have branches for each section", Samarasinghe added.

To do all these things the Government and the Cabinet has given the nod to raise funds for these projects from external resources and the External Resource Department is working for funding for this programme and apparently the JICA has unofficially agreed to fund this programme.

"What we need is our own system and our own mechanism so that we can make very good forecasts for Sri Lanka with the assistance of other nations and their facilities, We have to work towards that. That is our aim," Samarasinghe added.

"But if meteorologists think this as yet another profession all these efforts will be futile because it was with their commitment and dedication they can properly collect data and give proper forecasts.

Otherwise they will not do their duty by the people", Samarasinghe added.