گسیل و انتقال ذرات گردوغبار در منطقه جازموریان(مطالعه موردی: طوفان گرد و غبار 24 الی 26 نوامبر 2016) مقالة

طوفانهای گرد و خاک ناشی از منابع فرسایش پذیر سطحی مانند بیابانها در سالهای اخیر از اصلی ترین بلایای طبیعی هستند که کشورهای منطقه خاورمیانه از جمله ایران با آن درگیر می باشند. بررسی و شناسایی الگوهای جوی موثر بر مناطق خشک و کویری می تواند در پیش بینی این طوفانها موثر باشد. یکی از روش های بررسی طوفانهای گرد و غبار استفاده از مدل های عددی است. هدف این تحقیق کاربرد مدل جفت شده پیش بینی عددی وضع هوا WRF/Chem و مدل HYSPLIT برای شبیه سازی رخداد طوفان گرد و غبار و دستیابی به روشی جهت پایش، پیش بینی و هشدار وضعیت رخداد طوفان است. در این تحقیق از طوفان 24 الی 26 نوامبر 2016 استفاده گردید نتایج نشان داد که گسیل گرد و غبار حوزه جازموریان تحت تاثیر جریانات غربی به سمت مرز پاکستان و استان های سیستان و بلوچستان حرکت می کند و تالاب جازموریان به عنوان مهمترین کانون گرد و غبار در حوزه مورد مطالعه شناسایی شد و میزان غلظت گرد و غبار گسیل شده از این منطقه گاهی به 5000 میکرگرم در متر مکعب می رسد. رعایت حق آبه زیست محیطی این تالاب از سوی وزارت نیرو که با احداث سد صفارود بر روی سرشاخه های هلیل رود زمینه وقوع طوفان های گرد و غبار را شدت بخشیده است مهمترین راهکار پیشنهادی این تحقیق می باشد.

Introduction Dust storms caused by erodible surface sources, such as deserts, have been one of the major natural disasters in recent years, affecting countries in the Middle East, including Iran. One of the major factors to formation the dust storms is the strong wind flow that can be created in the presence of low pressure systems in the potential. Therefore, the study and identification the atmospheric patterns can be effective in predicting these storms. One way to study dust storms is to use numerical models that can be used even for times when appropriate data is not available and also to predict these types of storms. Material and Method After statistical study of the phenomenon of "dust" and the factors affecting it in the Jazmourian basin, a severe and widespread event of "dust" in the Jazmourian basin is investigated. Then, to investigate the prevailing atmospheric currents in the region, the HYSPLIT model is implemented as a matrix and in a leading way. In the implementation of HYSPLIT model, GDAS meteorological data with horizontal separation of 0.5 degrees have been used. Using the output of this model, it is possible to study how dust particles are transferred from this area. Finally, each of the studied dust phenomena is simulated using the WRF-Chem model to determine how the dust is emitted and transmitted in the region. Result Leading HYSPLIT model output for November 28, 2016 UTC12 clock which was executed as a matrix with GDAS data with 0.5 degree horizontal separation for 36 hours at a height of 100 meters. The results showed that the particles from this region were affected by northwestern currents and were transferred to Sistan-Baluchestan province and the border between Iran and Pakistan. Aerosols optical depth of the output particles of the WRF-Chem model at UTC12 on November 24, 2016. Values higher than 0.5 indicate a high amount of suspended particles in the atmosphere in the study area. At this time, the highest light depth of particles is in the Strait of Hormuz and Qeshm Island, but the concentration of particles in a large part of Jazmourian region is between 0.4 to 0.6, which can indicate the presence of dust particles in the atmosphere. The results also show that the concentration of "dust" on the Oman Sea and the Persian Gulf is higher than 5000 micrograms per cubic meter. Also, the concentration of "dust" in Jazmorian region is high and is higher than 1500 micrograms per cubic meter. Also in some areas, the concentration of "dust" is more than 5000 micrograms per cubic meter. Discussion and conclusion In the present study, using the outputs of the WRF_Chem model, the dust phenomenon and its characteristics in the southeastern region of Iran have been identified. According to the results, the WRF_Chem model provides a reasonable estimate of the weather in the study area in terms of scale and time changes. By producing dust particle concentration distribution maps, areas of the simulation basin that have the maximum particle concentration were identified as the main sources of particle emission. In general, the performance of the WRF / Chem numerical model in this study confirms the applicability of this model in modeling and forecasting air quality, especially for air vents produced from natural emission sources such as erodible areas of deserts. The results showed that the studied dust phenomenon (November 24-27, 2016) dust particles from Jazmourian basin, were affected by northwestern currents and were transferred to Sistan and Baluchestan province and the border between Iran and Pakistan.Keywords: simulation, Dust storm, WRF/Chem model, MODIS. Discussion and conclusion In the present study, using the outputs of the WRF_Chem model, the dust phenomenon and its characteristics in the southeastern region of Iran have been identified. According to the results, the WRF_Chem model provides a reasonable estimate of the weather in the study area in terms of scale and time changes. By producing dust particle concentration distribution maps, areas of the simulation basin that have the maximum particle concentration were identified as the main sources of particle emission. In general, the performance of the WRF / Chem numerical model in this study confirms the applicability of this model in modeling and forecasting air quality, especially for air vents produced from natural emission sources such as erodible areas of deserts. The results showed that the studied dust phenomenon (November 24-27, 2016) dust particles from Jazmourian basin, were affected by northwestern currents and were transferred to Sistan and Baluchestan province and the border between Iran and Pakistan.