بگارگيري تصاوير ماهواره‌اي ماديس در منشأيابي و تعيين مسير طوفان‌هاي گردوغبار در غرب و جنوب غرب ايران

Using Modis satellite imagery in source finding and path determining of dust storms in western and southwestern Iran

اخيراً وقوع طوفان‌هاي گردوغبار در غرب و جنوب غرب كشور به وفورگزارش شده است. جمع آوري و تحليل به هنگام اطلاعات گردوغبار در مديريت بهينه براي مقابله و پيشگيري حائز اهميت است. لذا در اين تحقيق با هدف به روزرساني اطلاعات و پايش و مسير يابي گردوغبار در استان خوزستان و غرب كشور از داده‌هاي اقليمي و سنجش از دوري (دو دهه اخير) استفاده شد. استان خوزستان داراي 20 ايستگاه سينوپتيك مي‌باشد. در اين تحقيق از داده‌هاي ساعتي در بازه زماني 2010 تا 2017 استفاده شد، داده‌هاي ماهواره‌اي سنجنده ماديس محصول MOD021KM در تاريخ‌هاي مطابق با روزهاي گردغباري ثبت شده در ايستگاه، تهيه گرديد. جهت بارزسازي گردوغبار، تركيب رنگي واقعي و شاخص‌هاي گردوغباري(BTD ، NDDI) اعمال شد، سپس با استفاده از مدل هواشناسي HY SPLIT مسير و منشاء طوفان گردوغبار در سه تراژكتوري ارتفاعي بررسي و رديابي گرديد. پس از پايش گردوغبار، همبستگي شاخص‌هاي گردوغبار با متغيرهاي مستقل (پارامترهاي هواشناسي) مورد بررسي قرارگرفت، نتايج همبستگي نشان داد پارامترهاي هواشناسي دما و رطوبت رابطه‌اي با گردوغبارهاي استان خوزستان و غرب كشور نداشته‌اند، و از كشورهاي همسايه عراق، عربستان، سوريه و اردن وارد شده است بنابراين مي‌توان گردو غبار را پديده‌اي خارجي محسوب كرد.

Recently, dust storms have been widely reported in the west and southwest of the country. Dust collection and analysis is important for optimal management and prevention in dust management. According to the definition of the World Meteorological Organization, whenever the wind speed exceeds 15 meters per second and as a result a volume of dust enters the atmosphere so that the horizontal field of view reaches less than one kilometer (1000 meters), a dust storm is reported. The occurrence of dust in recent years in the western and southwestern regions of the country has been accompanied by many problems for the residents of these areas, which has gradually spread to other provinces, including the capital. Frequency of dust occurrence in an area due to factors such as surface type, grain size, soil texture, high wind speed, elevation and soil, uncovered soil, dry air conditions, soil moisture, vegetation, local and outdoor air system, Short-term rainfall depends on the extent of deforestation, long-term droughts, land use change and human activities. Therefore, in this study, with the aim of updating information and monitoring and routing of dust in Khuzestan province and the west of the country, climatic data and distance measurement (last two decades) were used. Khuzestan province has 20 synoptic stations. In this study, hourly data were used in the period of 2010 to 2017. The satellite data of Modis sensor product MOD021KM were prepared on the dates in accordance with the dust days recorded at the station. To detect dust, real color combination and dust indices (BTD, NDDI) were applied. Then, using the HY SPLIT meteorological model, the route and origin of the dust storm in three altitude trajectories were investigated and tracked. After dust monitoring, the correlation between dust indices and independent variables (meteorological parameters) was investigated. The correlation results showed that the meteorological parameters of temperature and humidity were not related to dust in Khuzestan province and the west of the country, and were imported from neighboring Iraq, Saudi Arabia, Syria and Jordan, so dust can be considered as external phenomena.