عنوان مقاله [English]
In this study has been used hourly data of dust 87 synoptic stations in the country in 2008. After extraction of dusty days in 2008 for each station, 1 July 2008 was chosen as a case study, because of having lower horizontal vision than 1000 m in most of the studied stations of the western part of Iran. Then, AVHRR images of NOAA satellite were used in order to detection and monitoring of the dust storm. The aims of this study are to recognize the capability of this sensor in separation of dusty area, identifying dusty sources entering to the country and the regions that are affected by those sources. In comparison whit band 4 of this sensor, in band 5, dust has more radiation and temperature than water vapor and inverse so the brightness temperature index between bands 4 and 5 known as BTD and AVI were employed for recognizing the dust phenomena in the images. In addition, bands of 2 and 4 this sensor were used for detection of the dust storm in order to evaluation their capabilities and also ability of supervised classification methods for this work. Results indicated that considering all studied methods, the brightness temperature indexes, despite of having some disadvantages and limitation, are proper for detection and monitoring this phenomenon in the AVHRR images. According to the results of monitoring, in 30 June, dust sources were in Iraq, the south Syria and the south Arabia. In 1 July, dust entered to west Iran and decreasing its intensity, had lasted until 4 July. In 5 July, it had flight out completely.