جستجوی مقالات مرتبط با کلیدواژه "توفان خاک" در نشریات گروه "جغرافیا"

Today, dust storms affect the lives of many people around the world and cause a lot of financial and human losses. Every year, Iran is affected by dust storms caused by internal sources and external dust sources located in neighboring countries. Semnan province has several dust-producing sources due to its geographical location, that affect not only this province, but also the neighboring provinces. The purpose of this study is to investigate the dust phenomenon of Semnan province and its monthly changes in the 15-year period, between 2003 and 2017. For this purpose, meteorological stations data of the province and the aerosol optical depth of satellite product have been investigated. Also, GOCART model has been used to estimate the amount of dust emissions from this region and to determine the vertical dust flux in Semnan province. The study of average dust flux showed that the highest values ​​of dust flux was in the southeast of Shahroud and then in the south of Shahroud, Damghan and Sorkheh. A monthly investigation showed that in all months, the average AOD in the southern half of Semnan province was higher than in the northern half. The highest levels of AOD were in May, April and June, and the highest amounts of dust flux were observed in March, June and July. Also, the prevailing wind direction was northeast and northeast, and this factor causes dust particles rising from this region and dust loading in the south of Semnan province and areas of Isfahan, Yazd and South Khorasan provinces.

Dust storm is One of the natural phenomena that has a great impact on human life and the environment. Every year, some countries in the world where dust sources are located are affected by soil storms. Also, many more countries that do not have sources of dust particles are affected by the transfer of dust particles. Dust storms damage human health and respiratory system, disrupt power lines, disrupt road and air transportation, and agricultural sector Severely affected. The most important sources of dust production are deserts. After that, dried lakes can be named as the second source of dust production in the world. Glaciers and altered agricultural lands are other sources of dust in the world The largest source of dust in the world is in the Africa that imports large amounts of dust particles into the Earth's atmosphere each year. The Sahara Desert is the largest desert in the world with an area of 9 million square kilometers and is located in 10 countries in North Africa. Kok et al showed that sub-Saharan Africa emits about half of the world's dust. Then, the dust sources in the Middle East and Central Asia are in the second place and 30% of the production sources of global dust storms are located in them. One of the most important dust regions is the East Asian deserts, which emit 11% of the world's dust particles. Therefore, the Middle East is one of the most important regions in the world where many soil sources are located. In the Middle East, most of the sources of dust are located in Iraq, Syria and Saudi Arabia, but some of these sources are located in Iran, although the sources of production in Iraq and Syria are less active, however, these springs affect different parts of Iran by producing dust storms. In addition to scattered domestic springs, the main springs producing dust in Iran include the dried parts of the lake and Hamoon wetland in the southeast, the dried parts of the Horalhvizeh wetland (Hur al-Azim) in the southwest and part Of dried Urmia Lake in northwestern Iran. Sistan and Baluchestan province, which is located in southeastern Iran, in addition to high temperatures and low rainfall, is affected by 120-day winds. Today, the occurrence of dust storms is one of the most important problems of many people in the world and every year it causes a lot of damage in various aspect of human life. Countries in the dust belt are most affected by this environmental problem. As a country in the Middle East, Iran has always been affected by dust storms, which mainly originated from dust sources in other countries. The purpose of this study is to investigate the dust phenomenon in southeastern Iran and the Hamoon region. For this purpose a severe dust case was examined on April 26-28 in the Hamoon Lake region. The investigation from April 26 to 28 showed that in some stations in the region, the horizontal visibility has reached less than 1 kilometer, and the true color images of the Modis sensor and the RGB of the MSG satellite shows well the dust mass in this area. Also, the corrected reflection image of the MODIS sensor has shown the dust mass more clearly. It seems that the optical depth of the particles by using the DT and DB algorithm with a resolution of 10 km overestimated the concentration of dust particles in the study area. Comparing the output of the WRF-Chem model with the MERRA2 model shows that both models show the intensity of dust concentration in the Hamoon area, although the output values of the WRF-Chem model are higher than the output surface concentration values of MERRA2 model. Comparing the output of surface dust concentration of these two models with the PM10 concentration measured in Zabol station, shows that the two models overestimated dust concentration in comparison with the reported station data. Also, in this case study, the mean square error (MSRT) of MERRA2 model in Zahedan station was low, which indicates the acceptable performance of this model in this station in this dust case. Furthermore, the MSE of WRF-Chem model in Zahedan station is high, which indicates the poor performance of this model in Zabol station.