شبیه‌سازی توزیع قائم سامانه ‏های گردوغبارزا در ارتباط با سامانه ‏های همدید و توپوگرافی در غرب ایران

نوع مقاله: مقاله علمی پژوهشی

نویسندگان

1 استاد گروه اقلیم‌شناسی، دانشگاه تبریز

2 استادیار گروه اقلیم‌شناسی، دانشگاه فردوسی مشهد

3 دکتری اقلیم‌شناسی، دانشگاه تبریز

چکیده

در این مطالعه، بر اساس خروجی‏های مدل WRF-CHEM، الگوهای توزیع قائم سامانه‏های گردوغبارزا در غرب ایران به دو دسته تقسیم شد: الگوهایی با توزیع قائم در حدود 5/6 کیلومتر و کمتر از 5/3 کیلومتر. الگوهای همدید رخداد گردوغبار در دورة سرد به دو دسته تقسیم می‌شود: جبهه‏ای و غیرجبهه‏ای. در الگوی اول جبهه‏ای، بیشینة ارتفاع گردوغبار حدود 5/6 کیلومتر است و وابسته به شدت واگرایی در تراز میانی و سرعت قائم بالاسو و استقرار هستة جت بر فراز مناطق منشأ گردوغبار است. در الگوی دوم جبهه‏ای، بیشینة ارتفاع تودة گردوغبار کمتر از 4 کیلومتر است. در این الگو، ارتفاع محدودتر تودة گردوغبار وابسته به شدت محدودتر چرخندگی در تراز میانی و موقعیت جت است که عمدتاً بر فراز مناطق منشأ گردوغبار قرار ندارد. در الگوی غیر جبهه‏ای، پهنه‏های وسیعی از خاورمیانه تحت تأثیر استقرار یک پشته قرار می‏گیرد و الگوی گردشی در تراز زیرین تروپوسفر در شکل‏گیری گردوغبار مؤثر است. ارتفاع گردوغبار در این الگو حدود 5/3 کیلومتر است. همچنین، مهم‌ترین عامل در محدودشدن ارتفاع تودة گردوغبار در غرب ایران ماهیت سامانه‏های جوّی است. مانع کوهستانی زاگرس در انتشار قائم و افقی گردوغبار اهمیت کمتری دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Analysis of vertical distribution patterns of dust storms in association with atmospheric circulation patterns and topography in western Iran

نویسندگان [English]

  • Behruz Sari Sarraf 1
  • Ali Akbar Rasouli 1
  • Azar Zarrin 2
  • Mohammad Saeed Najafi 3
1 Professor of Climatology, Faculty of Geography and Planning, University of Tabriz, Iran
2 Assistant Professor of Climatology, Ferdowsi University of Mashhad
3 PhD Student in Climatology, Faculty of Geography and Planning, University of Tabriz, Iran
چکیده [English]

Introduction
The west and southwest areas of Iran are characterized by high-levels of dust events mainly due to their location in the vicinity of vast deserts. Western Iran is located in the vicinity of some important dust sources: the Tigris and Euphrates basin in Iraq as well as Syria in the west and the Arabian Peninsula in the south. These sources are among the most active in the dust belt, especially in the recent years.
Overall, sand and dust storms are the most important atmospheric phenomena in arid and semi-arid regions. They have been recognized as the regions with a wide range of environmental and climate impacts including distractive effects upon air quality and human health, agricultural activities, land use and soil formation. They are also recognized as the factor of desertification. Dust particles are important components of the earth’s climate system as they affect the balance of solar radiation by scattering and absorption. These feedbacks have a direct link with the intensity and height of the column of dust in the troposphere. The aim of current study is to understand the vertical distribution patterns of Middle Eastern Dust Storms (MEDS) associated with atmospheric circulation patterns and topography in cold period of the year (November-May) in west Iran.
 
Material and methods
The horizontal and vertical distribution of dust aerosols was simulated with chemistry/aerosol module of Weather Research Forecast system (WRF-CHEM). The WRF–Chem was configured with the Goddard global ozone chemistry aerosol radiation and transport (GOCART) dust emission scheme to calculate the influx of dust into the atmosphere. The effect of the Zagros Mountains on vertical and horizontal distribution of dust emission was also examined by WRF model in an area between 16º–44ºN and 33º–65ºE with a 30 km horizontal grid spacing. The FNL re-analysis data set were used to provide the initial and lateral boundary conditions in a control run and in a simulation run by removing the Zagros Mountains.
The atmospheric circulation pattern was investigated to explain the mechanisms of dust emission in the Middle East and its vertical emission over this region. The hourly visibility and dust dataset of 34 synoptic stations in the western part of Iran were obtained from the Iran Meteorological Organization (in 2004-2013 period) to extract dust events in the study area. The NCEP/NCAR 6-hourly reanalysis dataset with 2.5°×2.5° horizontal resolution was used for this period.
 
Results and discussion
The atmospheric circulation patterns lead to generation of dust events in the Arabian region in two categories of frontal and non-frontal patterns. In the frontal events of MEDS that occur in the cold period of the year, dust is created under the influence of emigrate systems of westerly winds setting in the Middle East region. Formation of a divergence system in mid-level of troposphere (500 hPa) leads to formation of a surface convergence center as well as frontogenesis, air uplift and atmospheric instability condition in the source areas of MEDS. In addition the Polar Jetstream position as one of the enhancing factors of instabilities and air uplift in the region has a key function in vertical distribution of MEDS. Generally, MEDS events occurred due to the frontal pattern are similar to the precipitation systems except the lack of humidity in case of dust generation in arid lands of the Middle East. Frontal patterns are divided into two patterns including Trough and Blocking. These two patterns are the dominant patterns of dust generation in November to May in this region in cold period. In frontal pattern, the vertical distribution of column dust is divided into two categories: in first pattern the maximum height of dust is above 7 km and in second pattern the maximum height is below 4 km. These patterns are related to the position and strength of Polar Jetstream, the strength of mid-levels vorticity, and upward motions of air flow. In the first vertical distribution pattern, there is upward motion to the 9 km of the troposphere as in second pattern the upward motion is 5 km of the troposphere.
In non-frontal pattern neither frontogenesis happens nor there is a polar front Jetstream which causes instabilities in the Middle East dust storm sources. Dust generation is due to the regional circulation system in the lower level of troposphere. In this pattern, the concentration of dust load is less than frontal MEDS and the maximum height of column dust is below 3.5 km.
The results of the analysis about the impact of topography on vertical and horizontal distribution of MEDS reveal that the Zagros Mountains have a limited effect on the vertical and horizontal distribution of MEDS. However, in the absence of the Zagros Mountains and the main factor which control the vertical and horizontal distribution pf dust storm is the strength of atmospheric systems.
 
Conclusion
Two main patterns of cold period of MEDS are frontal and non-frontal patterns. The vertical distribution of column dust in mentioned patterns are different. In frontal pattern the height of dust is varied from 4 to 7 km in the troposphere. The position and strength of Polar Jetstream, the strength of mid-levels vorticity, upward motions of air flow and divergence of moisture flux in MEDS sources are the most important factors which determine the strength and height of dust storm in the Middle East in the cold period. In non-frontal pattern the concentration of dust in the troposphere is below 3.5 km. the result of this study reveals that the important strength of atmospheric systems is more than topography barrier in vertical and horizontal transport of MEDS in west Iran.

کلیدواژه‌ها [English]

  • atmospheric circulation patterns
  • column dust height
  • frontogenesis
  • Zagros Mountains
بابایی فینی، ا.؛ صفرراد، ط. و کریمی م. (1395). تحلیل و شناسایی الگوهای همدیدی طوفان‏های گردوغبار غرب ایران، جغرافیاومخاطراتمحیطی، 17: 105-120.

باعقیده، م. و احمدی ح. (1393). تحلیل مخاطرة گردوغبار و روند تغییرات آن در غرب و جنوب غرب ایران، فصلنامة امدادونجات، 22: 43-60.

خسروی، م. (1389). بررسی توزیع عمودی گردوغبار ناشی از طوفان در خاورمیانه با استفاده از مدل NAAPS، مورد سیستان ایران، مجموعهمقالاتچهارمینکنگرةبینالمللیجغرافیدانانجهاناسلام.

خوش‌اخلاق، ف.؛ نجفی، م.‌س. و صمدی، م. (1391). واکاوی همدید رخداد گردوغبار بهاره در غرب ایران، پژوهشهایجغرافیایطبیعی، 80: 99-124.

رنجبر سعادت‌آبادی، ع. و عزیزی، ق. (1391). مطالعۀ الگوهای هواشناسی، شناسایی چشمه‌های تولید گردوغبار و مسیر حرکت ذرات معلق برای توفان جولای 2009، پژوهش‌های جغرافیای طبیعی، 44 (3): 73-92.

عزیزی، ق.؛ شمسی‌پور، ع.‌ا.‏؛ میری، م. و صفرراد، ط. (1391). تحلیل آماری- همدیدی پدیدة گردوغبار در نیمة غربی ایران، محیطشناسی، 63: 73-84.

عساکره، ح.؛ مسعودیان، س. ا. و شادمان، ح. (1392). تحلیل همدید پویشی فراگیرترین روز گرم ایران طی سال ۱۳۴۰ تا سال ۱۳۸۶، جغرافیاومخاطراتمحیطی، 7: 35-52.

کریمی احمدآباد، م. و شکوهی رازی، ک. (1391). اندرکنش گردش جوّ و پوشش سطح زمین در سازوکار تشکیل و گسترش طوفان‌های گردوغبار تابستانة خاورمیانه، پژوهش‌هایجغرافیایطبیعی، 78: 113-130.

کریمی، م. (1386). تحلیل منابع رطوبت بارش‏های ایران، رسالة دورة دکتری، به راهنمایی دکتر منوچهر فرج‏زاده، دانشگاه تربیت مدرس.

مفیدی، ع. و جعفری، س. (1391). بررسی نقش گردش منطقه‌ای جوّ بر روی خاورمیانه در وقوع طوفان‌های گردوغباری تابستانه در جنوب غرب ایران، مطالعاتجغرافیاییمناطقخشک، 5: 17-45.

Abdi Vishkaee, F.; Flamant, J.; Cuesta, F.C.; lamant, P. and Khalesifard, H.R. (2011). Multiplatform observations of dust vertical distribution during transport over northwest Iran in the summertime, J. Geophys. Res., 116, D05206, doi:10.1029/2010JD014573.

Alizadeh Choobari, O.; Zawar-Reza, P. and Sturman, A. (2014a). The global distribution of mineral dust and its impacts on the climate system: A review, Atmospheric Research, 138: 152-165.

Alizadeh Choobari, O.; Zawar-Reza, P. and Sturman, A. (2014b). The “wind of 120 days” and dust storm activity over the Sistan Basin, Atmospheric Research, 143: 328-341.

Alizadeh-Choobari, O.; Ghafarian. P. and Owlad, E. (2016). Temporal variations in the frequency and concentration of dust events over Iran based on surface observations, Int J Climatol, 36(4):2050-2062.

Asakereh, H.; Masoodian, S.A. and Shadman, A. (2013). Synoptic and dynamic analysis of most pervasive hot day in Iran during 1964-2009, Geog. and Environ. Haz., 7: 35-52.

Azizi, G.; Shamsipour, A.A.; Miri, M. and Safarrad, T. (2012a). Statistic and Synoptic Analysis of Dust Phenomena in West of Iran, Journal of environmental studies, 38(3):123-134.

Azizi, G.; Shamsipour, A.A.; Miri, M. and Safarrad, T. (2012b). Synoptic and remote sensing analysis of dust events in southwestern Iran, Natural Hazards, 64(2): 1625-1638.

Baaghideh, M. and Ahmadi, H. (2014). The analysis of dust storm hazard occurrence and its variations trend in west & southwest of Iran, Scientific Journal of Rescue & Relief, 6(22): 43-60.

Babaee Fini, O.; Safarrad, T. and Karimi, M. (2016). Analysis and Identification of Synoptic Patterns of Dust Storms in the West of Iran, Geography and Environmental Hazards, 17: 105-120.

Cavalieri, O.; Cairo, F.; Fierli, F.; Di Donfrancesco, G.; Snels, M.; Viterbini, M.; Cardillo, F.; Chatenet, B. Formenti, P.; Marticorena, B. and Rajot, J.L. (2010). Variability of aerosol vertical distribution in the Sahel, Atmos. Chem. Phys., 10: 12005-12023.

Chen, F. and Dudhia, J. (2001). Coupling an advanced land surface/hydrology model with the Penn State/NCAR MM5 modeling system. Part I: Model description and implementation, Mon. Weather Rev., 129: 569-585.

Engelstaedter, S.; Tegen, I.; and Washington, R. (2006). North African dust emissions and transport, Earth-Sci. Rev., 79: 73-100.

Ginoux, P.; Chin, M.; Tegen, I.; Prospero, J.; Holben, B.; Dubovik, O. and Lin, S.J. (2001). Sources and distributions of dust aerosols simulated with the GOCART model: J. Geophys. Res., 106: 20255-20273.

Grell, G.A.; Peckham, S.E.; Schmitz, R.; McKeen, S.A.; Frost, G.; Skamarock, W.C. and Eder, B. (2005). Fully coupled online chemistry within the WRF model, Atmos. Environ., 39: 6957-6975.

Grell, G. A. and Devenyi, D. (2002), A generalized approach to parameterizing convection combining ensemble and data assimilation techniques, Geophys. Res. Lett., 29 (14): 381-384.

Hamidi, M.; Kavianpour, M.R. and Shao, Y. (2013). Synoptic Analysis of Dust Storms in the Middle East, Asia-Pacific J Atmos Sci, 49(3): 279-286.

Hojati, S.; Khademi, H.; Faz Cano, A. and Landi, A. (2011). Characteristics of dust deposited along a transect between central Iran and the Zagros Mountains, Catena J., 88:27-36.

Hong, S.Y. (2010). A new stable boundary-layer mixing scheme and its impact on the simulated East Asian summer monsoon, Q. J. R. Meteorol. Soc., 136(651): 1481-1496.

Huang, J.P.; Fu, Q.; Su, J.; Tang, Q.; Minnis, P.; Hu, Y.; Yi, Y. and Zhao, Q. (2009). Taklimakan dust aerosol radiative heating derived from CALIPSO observations using the Fu-Liou radiation model with CERES constraints, Atmos. Chem. Phys., 9: 4011-4021.

Huang, X.; Wang, T.; Jiang, F.; Liao, J.; Cai1, Y.; Yin, Ch.; Zhu, J. and Han, Y. (2013). Studies on a Severe Dust Storm in East Asia and Its Impact on the Air Quality of Nanjing, China, Aerosol and Air Quality Research, 13: 179-193.

Janjic, Z.I. (2001). Nonsingular Implementation of the Mellor-Yamada Level 2.5 Scheme in the NCEP Meso model, NCEP Office Note, 437, available at: http://www.emc.ncep.noaa.gov.

Karimi AhmadAbad, M. (2008). Analysis of the moisture supply sources for Iran’s precipitation. PhD, Thesis. Tarbiat Modarres University, School of Humanities.

Karimi AhmadAbad, M. and Shakouhi Razi, K. (2012). Interaction between Atmospheric Circulation and Land Cover in the Mechanism of Creation of Summertime Dust Storms in Middle East (Case Study, July 2009), Physical Geography Research Quarterly, 78: 113-130.

Khoshakhllagh, F.; Najafi, M.S. and Samadi, M. (2012). An Analysis on Synoptic Patterns of Springtime Dust Occurrence in West of Iran, Physical Geography, 2(80): 99-124.

Khosravi, M. (2010). A Survey on the Vertical Distribution of Dust and Particle to Arise fromStorms in Middle East Case study: Sistan, Iran, The Forth International congress of the Islamic world Geographers, Zahedan, Iran.

Li, Z.; Niu, F.; Fan, J.; Liu, Y.; Rosenfeld, D. and Ding, Y. (2011). Long-term impacts of aerosols on the vertical development of clouds and precipitation, Nat. Geosci., 4: 888-894.

Lin, Y.L.; Farley, R.D. and Orville, H.D. (1983). Bulk parameterization of the snow field in a cloud model, J. Clim. Appl. Meteorol., 22: 1065-1092.

Martin E. J., (2006). Mid-Latitude Atmospheric Dynamics: A First Course. Wiley. PP. 336.

Miri, A.; Ahmdi, H.; Ekhtesasi, M.; Panjehkeh, N. and Ghanbarie, A. (2010). Environmental and socio-economic impacts of dust storms in Sistan Region, J. of Environ. Studies, 66(3): 343-355.

Mofidi, A. and Jafari, S. (2011). The Role of Regional Atmospheric Circulation over the Middle East on the Occurrence of Summer Dust-storms in Southwest Iran, Arid regions Geographic Studies, 2(5):17-45.

Najafi, M.S.; Khoshakhlagh, F.; Zamanzadeh, S.M.; Shirazi, M.H.; Samadi, M. and Hajikhani, S. (2014). Characteristics of TSP loads during the Middle East Springtime Dust Storm (MESDS) in Western Iran, Arab J Geosci., 7(12): 5367-5381.

Prakash Jish, P.; Stenchikov, G.; Kalenderski, S.; Osipov, S. and Bangalath, H. (2015). The impact of dust storms on the Arabian Peninsula and the Red Sea, Atmos. Chem. Phys., 15: 199-222.

Samadi, M.; Darvishi, A.; Mohammadi, H.; Alavi Panah, S.K. and Najafi, M.S. (2014). Global dust Detection Index (GDDI); a new remotely sensed methodology for dust storms detection, Journal of Environmental Health Science and Engineering, 12: 20.

Shao, Y.; Wyrwoll, K.H.; Chappell, A.; Huang, J.; Lin, Z.; Mctainsh, G.H.; Mikami, M.; Tanaka, T.Y.; Wang, X. and Yoon, S. (2011). Dust cycle: An emerging core theme in Earth system science, Aeolian Res., 2: 181-204.

Soares, W.R. and Marengo, J.A. (2008). Assessments of moisture fluxes east of the Andes in South America in a global warming scenario, Int. J. Climatol, DOI: 10.1002/joc.1800.

Teixeira, J.C.; Carvalho, A.C.; Tuccella, P.; Curci, G. and Rocha, A. (2016). WRF-chem sensitivity to vertical resolution during a saharan dust event, Physics and Chem. of the Earth, 94: 188-195.

Wild, O.; Zhu, X. and Prather, M.J. (2000). Fast-J: accurate simulation of in- and below cloud photolysis in tropospheric chemical models, J. Atmos. Chem., 37: 245-282.

Zarasvandi, A.; Carranza, E.J.M.; Moore, F. and Rastmanesh, F. (2011). Spatio-temporal occurrences and mineralogical–geochemical characteristics of airborne dusts in Khuzestan Province (southwestern Iran), Journal of Geochemical Exploration, 111: 138-151.

Zhang, J. and Li, X.M. (2012). Vertical distribution of sand-dust aerosols and the relationships with atmospheric environment, Journal of Arid Land, 4(4): 357-368.