Improved weather forecasts predicted

Press, 24 June 1986, Page 26

Improved weather forecasts predicted

A significant improvement in the accuracy and reliability of weather forecasts is predicted by the New Zealand Meteorological Service following its purchase of Digital Equipment VAX computers and software worth $2.5 million. Dr Don Thomspon, the Assistant Director of facilities for the Meteorological Service, said the improvements would come largely from the ability to develop a more sophisticated mathematical model of the weather.

“Weather data is collected from satellites, weather balloons and ground-based observations and measurements taken in New Zealand and around the world,” he said.

“Complex mathematical equations are used to analyse and model this weather data and develop forecasts for the next 48 hours.

“With the new computer system, we can analyse the data better and develop a more complete weather model. This will result in a gradual, but noticeable improvement in the accuracy and realiability of 24-hour weather forecasts over the next year.”

Dr Thompson said forecasting the weather would never be totally reliable. However the current success rate in New Zealand was 75 per cent to 80 per cent.

“In Britain the use of very high speed ‘supercomputers’ is resulting in five-day forecasts with similar accuracy to former two-day forecasts.”

He said the accuracy of weather forecasting depended on two main factors — the completeness of the data and the availability of sufficient computer power to process and analyse the data.

“We collect our weather data through a network of observing stations which make observations at ground level

and in the upper atmosphere by balloons and radar. We also have stations on Raoul Island and Campbell Island and operate stations thorughout the Pacific. We use local staff, usually employed by their governments. In return we supply expertise and equipment. “We also have hundreds of volunteer observers around the country, ranging from people reporting rainfall, to those making full reports.” The Meterological Service is linked to a global weather model developed in Reading, England, at the European Centre for Medium Range Weather Forecasting. This is funded by a consortium of European countries and uses a Cray supercomputer to process the data. New Zealand is one of the largest providers of weather data to this global model. In return New Zealand receives free access to the processed five-day forecasts and other information to include in the New Zealand weather model.

The new VAX system will be able to incorporate data from the global model and further improve longer range forecasting. However, he said, the emphasis will be on the 24-hour and 48-hour forecasts.

Dr Thompson said the new computer systems will comprise a large VAX 8650 computer at the Wellington head office and two smaller MicroVAX II minicomputers, one in the Auckland office and one in the Christchurch office.

A high speed local area network in the head office will link up existing Digital Equipment computers to the new VAX 8650. This local area network, in turn, will be linked to the computers in Auckland and Christchurch.

He said Digital’s DECnet hardware and software is capable of operating over a wide range of transport mediums, including optical fibre

cable, satellites, broadband cable and the post office network.

Staff in all centres could access any data and use any software regardless of which computer it was stored on.

As well as the analysis and modelling functions, Digital’s All-In-I office automation software will provide electronic mail, word processing and other functions. Digital’s videotex software and a range of sophistacted software development tools will also be installed.

“We have a very large training requirement with many complex weather measuring devices in use,” said Dr Thompson. "The videotex will initially be used to carry out this training, but we hope to develop a public access system for detailed weather information for private pilots, fishermen, farmers and others with specific weather information needs.”

Dr Thompson said the public will derive other benefits from the new system, including a better public local weather service in Wellington and Cbristchurch and a much more complete historical record of weather patterns.

An important contribution would also be made to aviation. “Forecasts are made for the aviation Industry in a special, more precise format. They need to know cloud base, visibility, temperatures, wind direction and speed in numerical terms,” he said.

“Special observations are made at airports each hour which are sent to the Met. Office and are made available on the aviation fixed telecommunications network — run by the Civil Aviation Division. Most airports have access to that network.

“The improvement in quality and detail of our input into that network will be a valuable aid to air safety,” Dr Thompson said.