Document Details
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Document Type |
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Thesis |
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Document Title |
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ATMOSPHERIC AEROSOLS AND THEIR CLIMATE IMPACTS ON THE ARABIAN PENINSULA الهباء الجوي وتأثيراته على مناخ شبه الجزيرة العربية |
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Subject |
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Faculty of Meteorology, Environment and Arid Land Agriculture |
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Document Language |
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Arabic |
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Abstract |
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Aerosols affect human health, the global radiation budget, hydrological cycle, and the earth’s climate. Very few studies have investigated the significance of aerosols on the climate over the Arabian Peninsula. In the present research, real-time measurements for aerosol optical depth (AOD), particulate matter (PM) with diameters of <10 and 2.5 µm (PM10, and PM2.5, respectively), and black carbon (BC) were performed from December 2012 to December 2013 at Hada Al-Sham, a rural location approximately 60 km west of Jeddah, Saudi Arabia. The daily mean PM10, PM2.5, and BC concentrations were 94.7 µg/m3 (range, 22.6–406.6 µg/m3), 29.8 µg/m3 (range, 7.5–157.3 µg/m3), and 1899 ng/m3 (range, 15.0–6372 ng/m3), respectively. In addition, the following five types of aerosol were studied: mineral dust (DU), sulfate (SU), particulate organic matter (POM), sea salt (SS), and BC. Their direct and indirect effects on the climate of the Arabian Peninsula were analyzed over a 7-year period (2005–2011) by using the state-of-the-art global aerosol-climate model (ECHAM5-HAM) with the Greenhouse Gas—Air Pollution Interactions and Synergies inventory representing anthropogenic emissions. Deep Blue satellite data and AOD observations were used to validate the model, which underestimated the concentration of aerosols and angstrom components. AOD values extracted from the ECHAM5-HAM correlated favorably with AOD values measured at the ground (0.58) or by satellite (0.66). DU and SU were found to constitute more than 86% of the total mass of aerosols over the Arabian Peninsula. The mean mass percentages of DU, SU, POM, SS, and BC were 43.7%, 42.5%, 7.7%, 4.5%, and 1.7% respectively. Seasonality varied for each aerosol and for each region. The longest season was observed for DU, which lasted for 7 months starting from March, and SU had a season of 4 months starting from June. Most of the aerosols were in the accumulation modes (53%), soluble coarse mode (33%), and insoluble coarse mode (12%). The direct and indirect aerosol effects on temperature, net top-of-the-atmosphere shortwave radiation for clear and all-sky cases, precipitation, cloud cover, and evaporation varied slightly between regions. The mean direct aerosol effects for temperature and precipitation were negative (−0.45 °C and −1.76 mm/month, respectively), but they were offset by the indirect aerosol effect, resulting in a positive total effect (0.09 °C and 0.17 mm/month, respectively). The results support icing theory because the total effects of aerosols in warm thin clouds can increase precipitation and temperature as a result of various cloud feedback mechanisms. A national aerosol monitoring network program could lead to a more accurate assessment of air quality in the region to protect human health, especially during Hajj and Ramadan. Further research into aerosol physics and modeling are required to guide programmers to improve their models so that climate simulations can more accurately represent aerosols over the Arabian Peninsula. |
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Supervisor |
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Prof. Mamdouh I. Khoder |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1438 AH
2017 AD |
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Co-Supervisor |
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Prof. Mansour A. Almazroui |
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Added Date |
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Monday, May 29, 2017 |
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Researchers
| فيصل مكي آل زواد | AlZawad, Faisal Makki | Researcher | Doctorate | |
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