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Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
Shuttle Imaging Radar (SIR-A) interpretation of the Kashgar region 
in western Xinjiang, China 
Dirk Werle 
F.G.Bercha, Ontario, Ltd., RADARSATProject Office, Ottawa, Canada 
ABSTRACT: The radar backscattering response of natural terrain in western Xinjiang and distinct man-made 
features associated with land use and water resource management in the oasis of Kashgar is investigated using 
SIR-A imagery. The brightness levels of the radar image signatures correlate well with the surface roughness 
of various terrain units. Different backscattering effects of vegetation provide a detailed assessment of 
cultivated areas and particularly forested windshelter belts, due to dominant volume scattering effects of the 
tree canopy. The elaborate pattern of windshelter belts along the irrigation and drainage canal system, road 
network and field boundaries serves as an excellent indicator for the classification of traditional cultivated 
land, recent land reclamation areas and for the success of afforestation efforts. Spaceborne imaging radar 
offers innovative mapping and monitoring capabilities with regard to regional terrain evaluation and land use 
analysis in the arid regions of Central Asia. 
1 INTRODUCTION 
In November 1981 the experimental Shuttle Imaging 
Radar (SIR-A) system onboard the space shuttle 
'Columbia' imaged approximately 10 million km 2 of 
terrain including partial coverage of China. 
Preliminary image analyses of arid environments have 
shown that the radar view provides a new way to 
examine problems of land reclamation, water 
utilization, soil erosion and salinization (Cimino 
and Elachi 1982) and terrain analysis (Woldai 1983). 
Spaceborne Synthetic Aperture Radar (SAR) offers an 
alternative imaging technique to optical satellite 
sensor systems, the operational performance of which 
is restricted by changing solar illumination and 
atmospheric conditions. Data acquisition by optical 
sensors is frequently limited by cloud coverage over 
the area of interest. Radar which uses microwave 
frequencies can obtain data regardless of cloud cover 
or darkness. 
Over the past decades, increasing population 
pressure as well as political and strategic 
considerations have led to further development of 
marginal agricultural land in Xinjiang Province along 
the western periphery of China (Weggel 1984). Remote 
sensing, and LANDSAT image interpretation in 
particular, has been applied in terrain analysis, 
regional resource assessment, land use monitoring, 
and for surveying and mapping purposes (Zhao 1984, 
Zhao and Han 1981, Zhao and Xia 1984, Chu 1982, 
Edelmann 1979). 
A combination of geographical factors, i.e. the 
position in the interior of the Asian continent and 
the framing by high mountain ranges, have created 
diverse environmental and physiographic conditions in 
the Kashgar region. This has resulted in specific 
adaptations of the cultural landscape in which the 
oasis of Kashgar, once one of the important nodal 
points along the ancient Silk Road, still commands a 
prominent position as China's westernmost outpost in 
Central Asia. 
This study is an attempt to provide a synoptic 
interpretation and an assessment of SIR-A imagery 
with regard to physical and cultural landscape 
features of the Kashgar region. Visual image inter 
pretation methods were used in the identification of 
terrain categories and forested windshelter belts. 
This was followed by an examination of the regional 
water supply and the associated spatial arrangements 
of the oasis-agriculture. 
2 THE STUDY AREA 
The study area is defined by available SIR-A coverage 
along data take 7 between 74°45'E and 76°45'E and is 
approximately 9,000 km 2 in areal extent (Figure 1). 
Over a distance of less than 70 kilometres, the 
Kashgar region reveals a diversity of topographic 
features and extreme climatic gradients and 
hydrologic conditions. These factors determine the 
relationship of the oases along the fringe of the 
Taklimakan Desert in the Tarim Basin at 1,550 metres 
to the surrounding glacier-topped mountain ranges of 
the Pamirs with altitudes exceeding 7,500 metres. 
Based on an integrated landscape approach, Zhao 
(1984) classified terrain in western China into seven 
categories, all of which may be found within the 
study area: clay and silt level terrain, sandy level 
terrain, stony gravel level terrain, denudational 
mountain and hilly terrain, erosional high mountain 
terrain, nival alpine terrain, and oasis (planted 
vegetation). 
The outstanding feature of the climatic conditions 
in the western Tarim Basin is the exceptional 
aridness. Kashgar receives less than 70 mm of 
precipitation annually (Figure 2). The annual 
temperature regime characterizes the climate as 
cool-temperate. Westerly and north-westerly wind 
Figure 1. Location map of the study area.