Athena Review Image Archive: Angkor viewed by SIR-C radar image

Athena Review Image Archive ^™

Angkor by Satellite: SIR-C radar image of the Khmer center

One of the most effective imaging sources devised by NASA/ JPL is the Spaceborne Imaging Radar - C/X band Synthetic Aperture Radar method (SIR-C/X-SAR). The three microwave wavelengths, L-band (24 cm), C-band (6 cm) and X-band (3 cm), allow detailed observations at any time, regardless of weather or sunlight conditions.

Radar images from the space shuttle Endeavor on Sept. 30, 1994 shows the huge ancient ceremonial complex and city of Angkor, Cambodia (lat. 13.43 N; long. 103.9 E). The pictures, covering an area of 55 by 85 km, are revealing new settlement data on this major Khmer site occupied beween the 9th and 15th centuries AD by more than 60 temples and a million residents.

[Figs.1,2: detail of SIR-C image (NASA-JPL P-45156 ).]

The city was organized around several vast reservoirs (large dark rectangles, numbered 3, 4, and 6), interconnected by canals used for transportation and irrigationthroughout the entire central zone. The main temple complexes, including Angkor Wat (2), the larger Angkor Thom (1), and Preah Khan (5) have been studied for many years. Most of the region is covered by rainforest, making visual air surveys difficult. Aided by the new radar satellite imagery, however, the areas north of Angkor Thom are now yielding up secrets of previously unknown structures and canals. At right, east of the central zone, are other outlying temple groups. One, visible as a bright rectangle surrounded by a dark reservoir (7 on detail), contained the temple complex named Chau Srei Vibol.

Of the many remarkable temple complexes at Angkor, those of Angkor Thom (1) may be singled out as some of the most impressive religious structures ever made. Looming high over the tropical rainforest, the Bayon temple group of the early 13th century AD includes massive towers with heads of the Buddhist deity Bodhissatva. Bayon was erected by the last of the great Khmer kings, Jayavarman VII, who ruled from 1181-1219 AD after Angkor had been invaded and sacked by a rival kingdom, the Chams. The court of Jayavarman VII in the rebuilt city included a widespread bureaucracy, and monasteries containing thousands of priests and officials. Many of the other large temple groups throughout Angkor were also rebuilt by Jayavarman, including Ta Proem (completed in 1186), and Preah Khan (completed in 1191).

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