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Many invaluable underwater buildings of archaeological interest in Alexandria were discovered in 1996 at different sites in the Eastern Harbour of Alexandria. There is a belief that the best way to protect these invaluable heritages is to transfer them to an underwater park or museum. Obviously, the execution of such a project depends essentially upon the water quality (including water transparency) improving in the future. The harbour is presently polluted by discharge of wastewater effluents from different sources. It has recently been decided to restore this important coastal area through: (1) stopping the direct discharge of wastewater effluents into this semi-enclosed harbour in 1993 and (2) gradually reducing the discharge of the municipal wastewater through marine outfalls at two sites lying at the outer sides of the harbour. Zero discharge is expected to be effective by the end of the year 2001. The present work, therefore, is a follow up of the study of water quality in the harbour after 1993: in 1996 and 1999-2000. The water quality of an open sea reference station was also studied for comparison. The results reveal occurrence of an improvement of the environmental conditions in the harbour. The water has turned from being eutrophic to mesotrophic. The harbour is expected to become meso/oligotrophic as soon as the complete cessation of the discharge from the two outside sources is attained. 相似文献
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考虑天气情况对入射太阳辐射的影响,研究和分析日照时数、天气类型和辐射参数的关系,并将散射模型、透射率和散射比例与4种常用天气类型相对应。以佳木斯市辖区为例,采用ArcGIS的点太阳辐射分析批处理工具,对佳木斯辐射台站进行日入射太阳辐射分析。通过将默认情况和天气类型两种模拟结果与辐射台站的实测值进行分析和验证,获得两者的相关性R2分别为0.573 4和0.899 5。研究结果表明按不同天气类型进行中温带地区点太阳辐射分析的方法切实可行,并获得更好的点日太阳辐射模拟效果,其有利于研究不同天气类型下物理和生物过程模型所受到的太阳辐射影响。 相似文献
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将DEM、坡度和坡向作为地形因子,基于ENVI/IDL编写MT-CLIM模型批量处理程序,使用改进MTCLIM模型对小兴安岭地区的地面气象台站进行太阳辐射模拟,并将模拟结果分别与辐射台站实测数据和二次趋势面统计模型进行验证。研究结果表明:从整年上,其与辐射台站的拟合精度R2为0.813 3,其中,夏季模拟太阳辐射日值拟合精度偏低,而其与二次趋势面统计模型拟合精度R2值范围为0.571 3~0.793 3;采用改进的MT-CLIM模型模拟较大区域的太阳辐射,比统计模型具有更好的普适性和高效性,能获得较好的中高纬低山丘陵区模拟效果,且为森林生态过程模型的输入参数研究提供依据。 相似文献
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Khalid S. Aldamegh Hesham Hussein Moussa S. Nasser Al-Arifi Sayed S. R. Moustafa Moustafa Hemeda Moustafa 《Arabian Journal of Geosciences》2012,5(4):599-606
Focal mechanism solution of the 27th August 2009 earthquake (mb?=?4.0) that occurred in the Badr area, northwest of Saudi Arabia, approximately 50?km from the Red Sea has been determined from the P-wave first motion polarities. Results show normal faulting mechanism with a negligible component of strike-slip motion with NE T-axis direction. This type of mechanism is common with other earthquakes of the northwestern Saudi Arabia and is considered to present the tectonic movement of the region. The dominantly extensional tectonic regime in this province demonstrates the influence of NE extension in the Red Sea. The strikes of the solution are consistent with those of the main faults near the epicenter. Hypocentral location of this earthquake was carried out using the data from the King Abdulaziz City of Science and Technology Seismic Network, Saudi Arabia, and the Egyptian National Seismological Network, Egypt. The horizontal and vertical confidence estimates are 0.5?km for both. The local magnitude, M L, following the Richter??s original definition was also derived from ten digital three-component broadband seismograms. The average local magnitude determined in this study is 3.8?±?0.17. The estimated seismic moment of this event is $ {3}.{\hbox{7e}} + {14}\,{\hbox{Nm}}\left( {{M_{\rm{W}}} = {3}.{66}\pm 0.0{7}} \right) $ . 相似文献
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