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Modeling and Forecasting Dust Storms in Yazd Province

Hosseini Dehshiri, Shahabaddin | 2023

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 56714 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Firoozabadi, Bahar; Afshin, Hossein
  7. Abstract:
  8. The Yazd province is located in the dry and desert region of Iran and is constantly exposed to strong winds and dust storms due to its climatic conditions and geographical location. The first objective of this thesis is to assess the dust storm events that have occurred in Yazd province in order to identify their source and pathways of transport during the long-term period of 2012-2019. A novel multi-criteria framework for identifying the sources of dust storms and dust events in Yazd province has been presented using the HYSPLIT model. In this framework, the numerical results, along with geographical features, observational and satellite data, were used as criteria in the multi-criteria decision-making approach. The receiver-based models show that local dust sources have the greatest impact on dust storms during the warm seasons, while external dust sources in the west and southwest of Iran have the greatest impact during the cold seasons. The final results of the proposed multi-criteria framework for determining the sources of dust storms in Yazd province showed that the Dasht-e-Kavir is the most critical dust source. Among the receiver-based models, the cross-reference backward trajectory method was the most suitable performance in identifying dust sources. Another objective of this thesis is to provide proper predictions of dust storms in Yazd province. In this study, the modeling parameters were first optimally selected, and then the dust storm in Yazd province was numerically modeled using the open-source WRF-chem model. The grid parameters were selected using a new hierarchical framework based result’s independency, and total 22 configurations were modeled. Other important parameters in modeling were also evaluated using a multi-criteria decision-making approach. In this evaluation, 13 configurations were considered, and the effect of each physical and chemical parameter on the modeling results was examined. After determining the optimal parameters in modeling, the dust budget and dust radiative forcing were also examined in this region. To evaluate the effects of radiative forcing, modeling was performed with and without considering radiative forcing. The results showed that the computational domian has the greatest impact on the dust event prediction in Yazd province. The results of the grid independence framework showed that taking Iran into account and expanding to northern dust sources as the computational domain, starting the modeling at least two days before the event, using the nest domain with a cell size of 12 kilometers, 30 vertical layers, and a time step of 120 seconds are the optimal grid parameters. The results of the multi-criteria decision-making framework show that the ERA boundary and initial conditions, the ACM2 boundary layer schemes, and the NOAH land surface scheme are the optimal physical parameters, and the AFWA dust emission scheme and morphology-based dust source function are the optimal chemical parameters for modeling dust storms in Yazd province. The radiative budget evaluation results in four events showed that the central region of Iran is mostly affected by internal dust sources, and the amount of dust emission and deposition in Iran ranges from 700-1400 Gg and 50-90 Gg, respectively. The radiative forcing results assuming a clear sky showed that the net radiative forcing at the surface, in the atmosphere, and above the atmosphere of Yazd province ranges from -1.2 to -5.7 W/m2, 1.8 to 6.8 W/m2, and -3.1 to -1.5 W/m2, respectively
  9. Keywords:
  10. Dust Storm ; Multicriteria Decision Making ; Sensitivity Analysis ; Radiative Forcing Feedback ; Receptor Based Models ; Yazd Province ; Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT)Model

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