1995 Australia Prize
PROFESSOR RICHARD MOORE (USA)
Dr Richard Moore, Professor Emeritus of Computer and Electrical Engineering at the University of Kansas, was a pioneer in the field of microwave-based satellite remote sensing, a prolific inventor of new remote-sensing devices that helped revolutionise mapping and monitoring of the Earth's surface. He was also a major contributor to understanding how microwave signals vary with surface characteristics.
In 1957, before the US had even launched its first satellite, Prof Moore co-authored a research paper that described how a pulsed radar could be used as an altimeter to map the Barth's topography from orbit. By 1963 the US was preparing to launch the first generation of communications and weather satellites.
Prof Moore joined a NASA team, which investigated how short wavelength (microwave) radar systems could be used for satellite-based remote sensing. Microwave systems offered at least one significant advantage over visible light and infrared sensing systems: they could see the Earth's surface by day or night, and through dense cloud.
Prof Moore recognized the potential of synthetic aperture radar (SAR) for earth observation from space. Synthetic aperture radar employs a microwave beam that scanned across the Earths surface from orbit - or from a low-flying aircraft. The motion of the vehicle carrying the SAR produces images of the terrain below in a long, wide swathe. SARs flown on aircraft, unmanned spacecraft and the Space Shuttle have provided high-resolution, stereoscopic images of the Earth's land surfaces.
As early as 1965 Prof Moore and several colleagues put to NASA a proposal for a multi band orbiting SAR to study and map the Earth's surface at many different wavelengths. But their visionary project was rejected.
�In the 1960s the Moon was the name of the game,� he said.
�NASA had the idea of putting sophisticated satellites into orbit around the Moon to study its surface, but we were more interested in doing the same thing for the Earth. We had couched our proposal in terms of testing all these new instruments in Earth orbit, before sending similar instruments to the Moon.
The concept was finally realised 29 years later with the launch of the Space Shuttle carrying the SIR-C synthetic aperture radar system. SARs had flown previously on unmanned spacecraft, and Professor Moore was involved in some way with all but those from Russia. These included Seasat (US), ERS-l (European Space Agency), and JBRS-l (Japan), as well as single-band instruments (SIR-A and SIR-B) on earlier Space Shuttle flights.
In 1965 Prof Moore coined the name 'scatterometer' for a radar sensor that could measure how the Earth's surface scattered a microwave beam looking down on the Earth from space; the scattering characteristics reveal detail of the structure and composition of the surface, including phenomena such as waves on the surface of the ocean.
Prof Moore found that ripples on the ocean's surface scattered microwave beams in patterns which could be interpreted to reveal both the strength and direction of the prevailing winds. Radiometers, scatterometers, and SARs also monitor sea ice cover in polar regions; ice is a natural insulator, and in ocean areas free of ice, or with only a thin cover, heat transfer to the atmosphere can be a hundred times more rapid than in ice-covered areas, resulting in significant changes in the earths weather.
NASA began launching weather satellites equipped with radiometers in the early 1970s. NASA also had a scatterometer on the Seasat spacecraft, and European Space Agency has one on its ERS-1. They have helped revolutionise weather forecasting by mapping wind fields over remote oceanic regions where weather data is sparse - the technique has proved particularly valuable over tropical oceans, which are often obscured by dense cumulus cloud. SARs can also detect natural or man-made slicks on the ocean surface.
In the early 1970s Prof Moore helped develop a combined radiometer/scatterometer, called RADSCAT, for NASA. It was designed to explore the best ways to monitor the ocean's surface. The instrument was test-flown over the ocean on a C-l30 Starlifter aircraft, and also on NASA's Skylab.
Because microwave radars operate at wavelengths beyond the visible and infra-red spectrum, they 'see' aspects of the Earth's surface that are invisible at these wavelengths. This was dramatically demonstrated when RADSCAT aboard SEASAT scanned the Sahara Desert.
Because the sand was extremely low in moisture, the dunes became transparent to the radar, and instead of producing images of the desert's sandy surface, Seasat revealed ancient river beds below the desert Subsequently, SARs aboard the Space Shuttle produced large-scale images of ancient rivers beneath the Sahara, and beneath the deserts of north-western Australia.
Prof Moore's invention of the microwave scatterometer and promotion of spaceborne SAR allowed researchers to monitor soil moisture levels from space, as an aid to weather forecasting. Crops also scatter microwave radar beams in distinctive ways that vary with the moisture content and architecture of their foliage. To study crops, SAR is needed to distinguish between the different fields.
These applications depend on an understanding of how microwave sensors 'see' the Earth's surface. Since the early l970s, Prof Moore and his faculty colleagues and students conducted extensive experiments to determine how land and ocean surfaces, and agricultural landscapes, scatter and rediate microwave radiation. 'This information has been invaluable to agriculture, environment and resource managers, and weather forecasters.
In 1995, NASA launched a Canadian satellite carrying a sophisticated new synthetic- aperture radar, capable of more frequent imaging because of another of Prof. Moore's inventions, the SCANSAR. With its capacity to monitor any rapid change in features on the Earth's surface, it was expected to become one of the world's most powerful tools for monitoring global resources.
At the time of the award, Prof Moore was working on another microwave sensor to improve weather forecasting � which will monitor the dynamics of weather systems by observing rain and other cloud particles in motion.
Today, remote-sensing instruments designed, developed, and promoted by Prof Moore are used worldwide for: