Dust Events in the Western Parts of Iran and the Relationship with Drought Expansion over the Dust-Source Areas in Iraq and Syria

Abstract

<p class="MsoNormal"> <span lang="EN-US">The most famous deserts exist in subtropical regions which is the direct outcome of insufficient precipitation and high temperatures. The <?xml:namespace prefix = st1 /><st1:place w:st="on">Middle East</st1:place> deserts are subjected often to dust, which reduces horizontal visibility to <st1:chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="True" sourcevalue="5" unitname="km">5 km</st1:chmetcnv>, and sometimes even to less than <st1:chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="True" sourcevalue="100" unitname="m"><st1:chmetcnv w:st="on" tcsc="0" numbertype="1" negative="False" hasspace="False" sourcevalue="100" unitname="m">100 </st1:chmetcnv>m</st1:chmetcnv>.</span><span lang="EN-US"> </span><span lang="EN-US">The severe and prolong drought recently afflicting the west <st1:place w:st="on">Asia</st1:place> region has been suggested to be instrumental in producing an increased output of dust into the atmosphere from the region.</span><span lang="EN-US"> </span><span lang="EN-US">Regarding the increasing of dust events over the west of Iran with the external origin in the recent decade (from 2000 to present), so the main dust-source areas over Iraq and Syria have been detected using the dust-source map of the southwest of Asia, satellite images and soil type maps. We considered the relationship between the increasing of dust events in the western of <st1:place w:st="on"><st1:country-region w:st="on">Iran</st1:country-region></st1:place> and drought expansion over the main dust-production areas during the recent decade. Dust frequency data series, and drought variables which include the VHI (vegetation health index), precipitation and temperature data series in long-term and monthly scales have been monitored and compared. And then we used the correlation analysis that indicated the significant proximity between the dust events and droughts/dryness in a yearly scale and also during the warm season (May to Aug). Meantime the derived results from the T-student test for the aforementioned data series confirm the fact that the droughts are parallel to the increasing of dust events from 1996 to 2011</span><span lang="EN-US"> </span><span lang="EN-US">(especially in the recent decade). We found that the recent droughts in the external dust source areas had the remarkable potential to increase the dust events in the west of <st1:place w:st="on"><st1:country-region w:st="on">Iran</st1:country-region></st1:place>.</span><span lang="EN-US"><?xml:namespace prefix = o /><o:p></o:p></span> </p

Identification of sand and dust storm source areas in Iran

“…Drought events, referring to the condition of an insufficient supply of water necessary to meet the demand, have a remarkable potential to increase dust events especially in the external SDS source areas (Zoljoodi et al, 2013). With inadequate rainfall and vast desert areas under dry climates, temperature and precipitation are considered as two important climatic factors causing the formation of sand and dust storms (Keramat et al, 2011).…”

“…The Iranian part of Al-Howizeh/Al-Azim marshes is mainly located in Khuzestan province. Sitting on the trajectory of SDS blowing from eastern Syria and Iraq, one of the most important SDS paths in West Asia (Zoljoodi et al, 2013), this area usually deposits sand particles to central and southwestern Iran. Sistan Basin, in addition to its significant impact on Sistan and Baluchistan province, is also an important source responsible for the dust storms in Pakistan and Afghanistan (Ekhtesasi and Gohari, 2013;Cao et al, 2014).…”

“…Except for indigenous source areas, most sand and dust storms that happened in Iran came from eastern Syria, Iraq and Arabian Peninsula (Zoljoodi et al, 2013). Under the influence of one of the most important trajectories of the summer "shamal", or "wind of 120 days" (Wilderson, 1991), dust particles originating from Syria and Iraq are always enhanced in the west of Iran (Morabbi, 2011;AZIZI et al, 2012), especially at the Iraq-Iran border (Rahimi et al, 2014).…”

“…In addition, other models, such as CARMA-dust model (Barnum et al, 2004) and GOCART model (Ginoux et al, 2001), are still being applied in SDS studies. In recent years, synthetic researches combining remote sensing, meteorological models and GIS tools have become more and more popular (Esmaili et al, 2006b;Gerivani et al, 2011;Hamidi et al, 2013;Zoljoodi et al, 2013;Cao et al, 2014).…”

Long-Term Variations of Aerosols Concentration over Ten Populated Cities in Iran based on Satellite Data

“…The second reason is that some dust sources in the Middle East such as Iraq, Syria and Arabian Peninsula contribute to dust production in the area. The wind direction in the warm/dry months can transport the dust from these regions to the western part of Iran [27]. The number of dust storms striking western Iran increased markedly between 2000 and 2009 by as much as 70 to 175 percent [28].…”