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1.
S. Farhadipour M. Azadi A. A. Bidokhti H. Sayyari O. Alizadeh Choobari 《Russian Meteorology and Hydrology》2018,43(9):613-624
In recent decades, the number of dust events has increased significantly in the west and southwest of Iran. In this research, a survey on the dust events during the period 1990–2013 is carried out using historical dust data collected from seven synoptic stations scattered across the west and southwest of Iran. Using statistical analysis of the observational data, two of the most severe dust storm events that occurred in the region on July 4–7, 2009 and June 17–20, 2012 were selected and analyzed synoptically. NCEP/NCAR reanalysis dataset was used to obtain the required fields including sea level pressure, surface wind field, geopotential height at 500 hPa, and wind and vertical motion at the 850 hPa level. Moreover, weather research and forecasting model coupled with chemistry (WRF-Chem) with two aerosol schemes, GOCART and MADE/SORGAM, were used to simulate the amount of particulate matter (PM10) and its transportation over the studied region. The initial and lateral boundary conditions of the model simulations are provided by Global Forecast System (GFS) data with the horizontal resolution of 0.5°. The calculations demonstrated that the MADE/SORGAM scheme predicted the values and trends of PM10 better than GOCART. Dust plums are formed over Iraq and Syria and then transported to the west and southwest of Iran. Comparing the MODIS satellite images for July 4, 2009 and June 18, 2012 with the corresponding model output showed the good performance of WRF-Chem in simulating the spatial distribution of dust. 相似文献
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Siahsarani Amir Karami Khaniki Ali Aliakbari Bidokhti Abbas-Ali Azadi Majid 《Ocean Science Journal》2021,56(3):225-240
Ocean Science Journal - A storm surge is a complex phenomenon in which current, tide, and waves interact with each other. Even if the wind is the main force of driving the surge, waves and tide are... 相似文献
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The effect of the Zagros Mountains on the formation and maintenance of the Iran Anticyclone using RegCM4 总被引：3，自引：0，他引：3
Azar Zarrin Hooshang Ghaemi Majid Azadi Abbas Mofidi Ebrahim Mirzaei 《Meteorology and Atmospheric Physics》2011,112(3-4):91-100
Iran anticyclone is one of the main features of the summer circulation over the Middle East in the middle and upper troposphere. To examine the effect of the Zagros Mountains on the formation and maintenance of the Iran anticyclone, an experiment was conducted by Regional Climate Model (RegCM4) in an area between 22°?C44°N and 35°?C70°E with a 40?km horizontal grid spacing. The NCEP/NCAR 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 result reveals that the Zagros Mountains have an important effect on the formation and maintenance of the low-level cyclonic circulation and mid-level anticyclonic circulation in summer. Examining the diabatic heating shows that the elimination of the Zagros Mountains causes a significant change in the heating values and its spatial distributions over the study area. Comparing the diabatic heating terms, the vertical advection term has the main contribution to the total heating. In the absence of the Zagros Mountains, the vertical advection and the mid-troposphere anticyclonic circulation are apparently weak and, therefore, the Iran subtropical anticyclone vanishes over the west of Iran. The study indicates that the Zagros Mountains as an elevated heat source have the main impact in the formation of a thermally driven circulation over the Middle East. 相似文献
4.
This paper presents a method for identification of the hydrodynamic coefficients of the dive plane of an autonomous underwater vehicle. The proposed identification method uses the governing equations of motion to estimate the coefficients of the linear damping, added mass and inertia, cross flow drag and control. Parts of data required by the proposed identification method are not measured by the onboard instruments. Hence, an optimal fusion algorithm is devised which estimates the required data accurately with a high sampling rate. To excite the dive plane dynamics and obtain the required measurements, diving maneuvers should be performed. Hence, a reliable controller with satisfactory performance and stability is needed. A cascaded controller is designed based on the coefficients obtained using a semi-empirical method and its robustness to the uncertainties is verified by the μ-analysis method. The performance and accuracy of the identification and fusion algorithms are investigated through 6-DOF numerical simulations of a realistic autonomous underwater vehicle. 相似文献
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To assess the susceptibility of five varieties of tobacco to ozone, nine rounds of fumigation experiments were performed. These tobacco varieties were exposed to a range of ozone concentrations in a single-pass chamber fumigation system for short periods. A dose of 7.5 pphm did not produce visible injury in any tobacco variety. Tobacco cultivars; Bel-B, Weather Fleck and ZZ100 exhibited no visible injury up to 26 pphm. However, doses in excess of 16 pphm caused visible injury in cultivars Bel-W3 and Dynes. Awareness of the susceptibility levels of these cultivars to ozone assist biological monitoring process in field experiments. Biomonitoring is considered to be a valuable method for ozone assessment for situations where air pollution monitoring by instruments in remote locations is too expensive. 相似文献
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During very considerable progress in industry and industrial centres development in late 20th and early 21st century, air pollution has become one of the most significant problems of mega cities. Thus, air pollution survey to exert abatement methods has a very important role. Various methods are available for air pollution monitoring which are very costly. Air pollution monitoring by susceptible plants as biological indicators are not only economic but also simple. In this paper, vast studies were done on the plants of around each Queensland Environmental Protection Agency (QEPA) monitoring sites. Around these sites susceptible plants to air pollution were neither available nor exist in all monitoring sites. Therefore, it seemed the best method is the portable exposure benches application with automatic watering system in five sites among all studied locations. In this research different varieties of tobacco like Weather fleck, Bel-B, Bel-W3, Dynes, ZZ100 were used to measure the impact of ozone as a pollutant on them. Parsley cv. Frizz and Leek cv. Vertina were selected as nitogen oxides indicators. In general, the above-mentioned plants were exposed to the ambient air in five sites around Brisbane from April 1997 to May 1998. The susceptible variety leaves of Bel-W3 showed injuries just in two sites. The reason for this is the high level of ozone and the effects of climatic factors in production and dispersion of it during the experiments. The survey results represent that ozone with elevated concentrations is available as far as 30km radius from Brisbane city centre. Within this area only the most susceptible plants’ leaves would be liable to suffer injury. 相似文献
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Integrated geophysical methods for determining geometry of the Kahrizak Fault,Tehran, Iran 总被引：1，自引：0，他引：1
Historical studies and geologic investigations show that the Kahrizak fault located at the southern foot of the central Alborz
Mountains poses a high seismic risk for the Tehran region. However, little is known about the geometry and mechanism of movement
along this seismogenic fault. This paper uses three different geophysical methods namely, seismic refraction, electrical resistivity
and magnetic techniques to investigate geometry and sense of motion across the Kahrizak fault in southern Tehran. Although
the geoelectric measurements do not show clear anomaly across the fault deep down into the ground, it reveals an obvious anomaly
in shallow depths. However, looking at the seismic refraction and magnetic profiles across the Kahrizak scarp, we identified
a high angle fault dipping south. This result in conjunction with the local relief across the fault scarp would suggest that
the southern block is downthrown with respect to the northern block across a normal fault. Such knowledge can contribute to
better evaluate the seismic hazard potential of one of the main seismogenic faults in the Tehran area. 相似文献
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