International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004
2. ENVIRONMENTAL
DEVELOPMENT OF THE REGION
In the absence of deforestation, grazing or cultivation the
modern climatic conditions would allow the vegetation typical
of the Terebinth-Almond Woodland steppe in the region of
Jebel Bishri. Changes in vegetation of the region took place 11
000 to 10 000 years ago, when the drastic retreat of the
woodland took place ca. 11 500 B.P. (See Moore et al., 2000).
The continuous zone of forest has not reached the area for past
ten thousand years, although occasional trees or small plots of
woods have existed. Only earlier in the Palaeolithic Stone Age
the area has obviously been greener exemplified by several
wadis and terraces which offer plenty of archaeological remains
of past human activities.
Nowadays the mountain of Jebel Bishri itself is practically
devoid of agriculture and constant combating against increasing
desertification is under way by ACSAD (The Arab Centre for
the Studies of Arid Zones and Dry Lands). During the past
hundred years the ecological balance of this Syrian steppe has
suffered major setbacks caused by grazing, gathering of
firewood, agriculture and increasing traffic. However, the
neighbourhood belongs to the perimeters of the so-called Fertile
Crescent and the cradle of agriculture. Ca. 100 kilometers
northwest from Jebel Bishri up the stream of the Euphrates lies
Abu Hureyra, the oldest agricultural site in the world. It offers
the earliest hither-to-known signs of domestication of cereals
(rye) dated to ca. 9000 B.C., i.e., to the Epipalaeolithic Period
by radiocarbon datings. Abu Hureyra is an important example
of the change from the mobile hunter-gatherer way of life to
sedentarization and the development of the village life. (See
Moore et al. 2000). The oases of El Kowm and Qdeir on the
western piedmont area of Jebel Bishri have offered comparable
evidence of the sedentarization and nomadization processes of
early humans. (See, e.g., Cauvin, 1982 and Zarins, 1989).
In order to visually approach the environmental contrasts of the
region the Finnish project SYGIS has used satellite data in
constructing a 3-- model of the border zone representing the
mountain and the alluvial zone of the Euphrates (see Figure 1.).
Figure 1. The 3-D-model of Jebel Bishri and the Euphrates
valley from the east. Construction by Markus Törmä, raw data
copyright: DLR and Eurimage
Monitoring changes from past to present in this environmental
border zone opens vistas for human responses to the
environment in space and time. Human groups have found
different strategies. to adapt to marginal environments. These
responses can be expressed in different economic and social
898
ways, and it is our task to delincate the responses in the
archaeological record.
But to avoid environmental determinism we ought to
understand that people also alter the environment: e.g.,
agriculture — causes sedimentation — and over-grazing
desertification. Different sources of satellite data from various
years offer excellent possibilities to detect changes in
desertification and river channel migration. Monitoring and
comparing environmental changes through satellite data in
different years elucidates the post-depositional processes and
preservation of archaeological remains in the area.
Understanding the change also offers us means to follow the
development in the area, find new sites buried by environmental
changes and to offer choices for planning new strategies of
preserving traditional economies and culture in the area.
3. DATA ACQUISITION,
PREPROCESSING AND
INTERPRETATION METHODS
Remote sensing data utilized so far consists of optical satellite
images and digital elevation models.
3.1 Satellite images
In order to determine the land cover of study area and its
changes as well as visualization purposes, following remote
sensing images have been acquired:
e 4 Landsat Multi-Spectral Scanner (MSS) images,
185/35 and 185/36 taken 27.6.1975 (Landsat 2) and
172/35 and 172/36 12.7.1983 (Landsat 4)
Downloaded from Global Land Cover Facility
(http://glcf.umiacs.umd.edu/).
e 2 Landsat Thematic Mapper (TM) images, 172/35 and
172/36 taken 1.9.1990 (Landsat 4). Downloaded from
Global Land Cover Facility (see the website above).
e Landsat Enhanced Thematic Mapper image, path 172,
row halfway 35 and 36, taken 29.1.1999. Acquired
from Novosat Ltd. Copyright Eurimage.
e QuickBird pan-sharpened multispectral image,
coordinate of the centre: lat. 35. 422, long. 39. 4788 ,
taken 15.7.2003. Acquired from Novosat Ltd.
Copyright Eurimage.
e. 3 CORONA images, taken 28.6.1966, 22.1.1967 and
22.1.1967, places S FWD 1034-2, S FWD 1038-2 and
S FWD 1038-2. Acquired from USGS.
The spatial and spectral properties of these images are presented
in Table 1. in the end of the article.
Landsat is a series of polar orbiting remote sensing satellites.
The first Landsat was launched 1972 and the last one, the
seventh, 1998. The most important instruments onboard
Landsat-satellites have been Multi-Spectral Scanner (MSS),
Thematic Mapper (TM) and Enhanced Thematic Mapper
(ETM). These instruments are electro-optical scanners which
produce digital data (Kramer, 1996). The main differences are
number of channels and their wavelengths and spatial resolution
(see Table I in the end of the article).
QuickBird is a modern digital imager with very high spatial
resolution, less than 1 meter on panchromatic channel. There
are also four multispectral channels (see Table 1 in the end of
the article). Due to the high spatial resolution, the image size is
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