The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
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26' 00' 26 30' 27' 00' 27’ 30’ 
26' 00' 26 30' -27 00' 27’ 30' 
Figure 1. Location map of the study area 
In the Menemen Plain, semi-dry and less humid mesothermal 
climate is dominant and the rain (which is 616 mm / m2) falls in 
the winter season. Thus, the summer season is drier. There is 
excessive sun light and evaporation in summer seasons. 
Relative humidity is around 50%. Although all crop types can 
be grown in the plain, the main products are cotton, com, and 
cereals. Viniculture is also common in the area. The land use 
types of the areas nearby the sea, which have become very salty 
due to improper drainage practices, are pastures. Texture of the 
plain soil is deep and composite. The Gediz River floodings 
have created plain fields, levees and depression 
géomorphologie formations in its surroundings (see Figure 1). 
Soil texture and distribution of the soil moisture in Menemen 
Plain is coherent with these geomorphological formations. 
While clay texture is dominant in depression fields, levee lands 
are sandy and over flow mantle plains have a loamy texture. 
The area has a micro relief however the slope in general is 1%. 
In a larger part of the study area, the fields were prepared for 
cotton and com farming before the seeding at the beginning of 
May 2006. The roughness of the unplanted study area was 
similar to that of the other fields in the study area. In this season, 
usually cotton is planted. Since the area has not received 
enough rain until the beginning of May, the soil moisture levels 
varied usually relating to their water holding capacities. 
Irrigation was started on the dates of the data acquisition. 
Therefore, estimated soil moisture is not the only natural soil 
moisture; there is also the moisture content of irrigated soils. 
4. MATERIAL S AND METHOD S USED 
4.1 Materials 
In order to validate the above concept, the image data used in 
this study were acquired by the ENVISAT-ASAR, ALOS- 
PALSAR and RADARSAT-1. RADARS AT-1 satellite image 
of 28 May 2006, ENVISAT-ASAR satellite image of 8 June 
2006 and ALOS-PALSAR satellite image of 10 June 2006 that 
include agricultural fields of Menemen Plain were used. The 
RADARSAT-1 operates at C band (5.332 GHz) with HH 
polarisation. It operates under 8 different beam modes (Fine, 
Standard, Wide, ScanSAR, Extanded Low, Extended High) 
with varying spatial and radiometric resolutions at various 
incidence angles between 20° and 49° (RSI 2000). Fine beam 
mode image with 6.25m x 6.25m resolution was selected from 
the 8 different beam modes. The ASAR (Advanced Synthetic 
Aperture Radar) operates in the C band. It can acquire images 
in both single and dual polarisations as HH, HV, and VV. The 
incidence angles vary between 15 ° and 45° (Baghdadi et al., 
2006). For this study a VV polarised image with the resolution 
of 12.5 m x 12.5m was selected. The PALSAR (Phased Array 
L-band Synthetic Aperture Radar) operates in L band and 
acquires images in five observation modes (Fine Beam Single 
(FBS), Fine Beam Dual (FBD), Direct Transmission (DT), 
ScanSAR and Polarimetry). The incidence angles range 
between 18° to 55°. It can acquire data in four polarisations 
(Rosenqvist et al., 2004). Fine beam mode with 6.25m x 6.25m 
resolution was selected from the five different beam modes. 
The detailed description of the SAR data used is given in (Table 
D- 
RADARSAT-1 
ASAR 
PALSAR 
Date 
28/05/2006 
08/06/200 
6 
10/06/2006 
Sensor 
SAR Fine 1 
ASAR/IM 
PALSAR/FBS 
Pixel Spacing 
6.25 m. 
12.5m. 
6.25 m. 
Orbit 
55139 
22112 
2010 
Flight 
direction 
Ascending 
Ascending 
Ascending 
Processing 
SGF 
PRI 
LI.5 
Polarization 
H/H 
V/V 
H/H 
Swath 
50 km 
ISI-105 
80 km 
Incidence 
Angle 
37-40 
15-22.9 
41.5 
Cadastral maps in 1/5000 scale and topographic maps in 1/25000 scale 
were used for the rectification as the ancillary data. An orthorectified 
SPOT image and SRTM data were used for the orthorectification of the 
SAR data. 
Table 1. Properties of the SAR data 
4.2 Methods 
For the geometric correction of SAR images, topographic maps, 
cadastral maps, and an orthorectified SPOT image were used. 
Geometric correction of SPOT-2 satellite images was 
implemented by map to image rectification by using cadastral 
maps in 1/5000 scale and topographic maps in 1/25000 scale. 
Sufficient number of spatially homogeneous ground control 
points was used, and the rectification accuracy was within 
acceptable limits. RMS error was smaller than 1 pixel (< 20 m). 
The RADARSAT, ASAR and PALSAR images were 
geometrically corrected by using both image-to-image and map 
to image rectification processes. Around the number of 40 
control points which were evenly distributed was selected per 
each SAR data from the rectified SPOT-2 image and from the 
topographic maps with a pixel RMS error less than 6.25 m, 
12.5m and 6.25 m for RADARSAT-1, ASAR and PALSAR 
images respectively. All images were registered to a UTM Zone 
35 ED50 datum. 
Field works were carried out for a ground truth data collection 
in synchronization to the RADARSAT-1 and ASAR and 
PALSAR passes. Sample points were chosen arbitrarily which 
were evenly distributed across the Menemen Plain in order to 
determine the soil characteristics. It has been noted that on the 
dates that the satellite images were taken, the area that included 
around 80 sampling points per each SAR image date was not 
covered by plants (i.e. the area was ready for summer planting 
or just seeded). The coordinates of the sample points were