Satellites Will Assist Weather Watch

Press, Volume CIX, Issue 32166, 9 December 1969, Page 23

Satellites Will Assist Weather Watch

Shortly after taking office President Nixon full United States; support for the World; Weather Watch, a co-eperative international plan to improve weatheryforecasting and develop / methods for making longer-range predictions! Australia and New Zealand are bothzparticipating in tins effort which owes its origin to a United Nations resolution almost eight years ago. In the meantime advances in weather satellites and computers together with the creation off a global network of meteorological centres have made ft possible to gather, process and disseminate weather information on a world-wide basis. The potential benefits of better weather prediction are immense, justifying the cost of the programme a thousand times over. The recent crop! losses due to untimely heavy! rains in New South Wales!

underline the fact that a substantial fraction of the world’s produce, worth untold billions of dollars annually, is lost because of bad weather. In the construction industry in the United States alone over a billion dollar* a year is lost through weather. Then there is the appalling toll of life and property when floods, gales and blizzards strike unexpectedly. And our coasts bear witness to the shipping log in storms at sea. f

Without the past decade of progress in space the World Weather Watch would have been prohibitively expensive, if not completely impractical. The fact that such an ambitious undertaking can be considered at all reflects the growing confidence in satellite technology. Weather satellites of the welVknown Tiros. Nimbus and ■ Essa series are now taken for granted—their cloud/ pictures and other weather- observations are used regularly by weather forecasters the world over. In fact, anyone with $2OOO worth of equipment can receive up-to-the-minute cloud pictures of | their own area by tuning in |to one of the satellites I equipped with the AT.T.

(Automatic Picture Transmission) system. Communications satellites also are playing a vital role in rapidly distributing weather observations and predictions while they are still fresh enough to be of value. The third essential element of a full-scale weather prediction service is the electronic computer. It is debatable whether satellites owe

more to the : development of efficient high-speed computers or vice-versa. Certainly only primitive satellites would have been possible without the benefit of computers, but on the other hand the demands of rocket guidance systems spurred the miniaturisation of electronic components to the extent where computers of fantastic capacity can be built small enough to fit inside, even a modest building. The vast flood of weather observations gathered during the World Weather Watch will be processed by highspeed computers at the three World Meteorological Centres located in Washington, Moscow and Melbourne. Their analyses and predictions flow to 22 regional meteorological centres for further distribution to national centres. In

• Australasia the regional centres are in Darwin and , Wellington, which also serves , as national centre for New , Zealand. The national centres ' provide weather maps and I forecasts for airlines, shipping and all other users ! including the public. At the same time the , national centres feed raw . weather data back up the line t to the world centres. Like the '■ weather itself these centres . are dynamic—they function 24 hours a day to keep ; abreast with the ever-chang-ing weather situation.

More Stations For the needs of the World Weather Watch the hundreds of weather stations dotted around the globe will be augmented by almost 100 more. As well as the traditional ground measurements of wind, temperature, humidity and pressure, most stations are or will be equipped with rawinsondes. Twice a day at set times these stations will release balloons which are tracked by radar to measure winds up to high altitudes. The balloons carry instruments which transmit temperatures and other measurements as they rise through the atmosphere. Even with hundreds of active observing stations the global weather pattern is only barely sampled. At the present time adequate data are available from less than 20 per cent of the earth. Complete coverage is out of the question. This is where the weather satellites are saving the situation. For an altogether modest sum, comparatively speaking,. they can provide global measurements of cloud cover by day and by night as well as the temperature of the surface of the earth or the tops of clouds. Vext month Tiros-M will be launched into orbit from California to provide these data on a continuous operational basis. Tiros-M is somewhat different from the earlier Tiros satellites and is the prototype for the second generation weather satellite system.

Testing Instruments Experimental weather satellites of the Nimbus series are at present testing Instruments for obtaining vertical profiles of temperature and humidity. When these instruments are incorporated in the operational satellites their value will be more than doubled. Other weather satellite , systems are in the planning stage. One of these is the Synchronous Meteorological Satellite (S.M.S.) which will pave the way for the Geostationary Operational Environment Satellites (G.0.E.5.). These satellites, in stationary positions 22,000 miles above the equator, will day and night photograph clouds covering one-third of the earth. The photographs will be frequent enough to provide wind information derived from the motion of the elouds. Next year N.A.S.A. plans to launch, a French-developed satellite: which will track up to 500 instrumented balloons. These will float at acdnstant pressure level- in the atmosphere and will be-tracked by the satellite to obtain wind information. Work is proceeding on the design of electronic packages to be carried by these balloons which tests have proved can last for more than a year and circle the earth many times. Another ’system will employ data buoys moored in oceans around the world. They will be interrogated by data-collection satellites as they pass in orbit Overhead.

Yet another idea which has scarcely hit the drawing board is a scheme employing pairs of satellites. Microwave signals beamed between them will be made to graze the surface of the earth to reveal the state of the sea, areas of rainfall on land, the water vapour content of the atmosphere and profiles of air temperature and density. The weather experts of the world apparently have no shortage of ideas for . making the best use of satellites in man’s unceasing quest to master the elements.