چکیده:
This study determined some spectral characteristics and relationship between Landsat spectral reflectance and soil surface color in the arid region of Iran (Kashan). The study carried out in the kashan area that covers 90000 ha. Consisting of mountain, hills and flood plain. Enhanced Thematic Mapper (ETM+) data collected on July 2002 were used for this research. The color composite images produced from ETM+7, ETM+4 and ETM+2 as red, green and blue respectively used in order to choose sample sites. The twelve sample sites were chosen based on resampled 3*3 pixels (90*90 m). In each site, the soil surface conditions and the munsell color of the soil surface were investigated in the field. Some physico-chemical properties of soil samples were also determined in the laboratory. Soil surface particle sizes were categorized into three classes: bare soil <2 mm in diameter, coarse fragment >2mm in diameter and vegetated soil. The results of this study indicates that munsell notation of hue, value and chroma are significantly correlated to the visible bands of Landsat (ETM+) data. From this study it may be concluded that visible reflectance of Landsat can be used to estimate soil color, if very precise result is not expected .More investigation are necessary in order to improve the obtained results.
خلاصه ماشینی:
ir, 2- Associated Professor, Faculty of Geography, University of Tehran, 3- Assistant Professor, Faculty of Agriculture, University of Tehran Abstract This study determined some spectral characteristics and relationship between Landsat spectral reflectance and soil surface color in the arid region of Iran (Kashan).
Keywords: Landsat7 (ETM+), visible bands, spectral properties, arid region, soil color Introduction Arid and semi-arid regions include 36% of the earth based on climatic and vegetation cover parameters.
The results of these reseaches especially during 1980 and 1981 showed that color and soil particle size are highly correlated with measured spectral reflectance of sattelite device or manual radiometer.
Escadafal et al (1988) studied the relation between spectral reflectance of Landsat and soil color and the results showed that in arid and semi arid regions, the Hue, value and chroma parameters have high correlation with Landsat data.
To obtain the relation between soil color and spectral reflectance of ETM+ sensor (Bands 1-7) Hue, value and chroma properties of samples were determined using visual and Munsel standard manual in each site (Table 1).
Escadafal et al (1988,1989) have studied the relation between soil color and spectral reflectance of Landsat which showed that Munsel color components (Hue,value) have significamt relation with Landast data.
It is suggested to define soil color exactly using visual methods based on measurement of spectral reflectance in laboratory to find differences.
Munsel soil color and soil reflectance in the visible spectral bands of Landsat MSS and TM data, Remote sen.