Memorial to Prof. Paolo Bono 1940–2012     

James W. LaMoreaux  Marco Petitta  Giuseppe Capelli  Hai Thanh Tran 《Environmental Earth Sciences》2013,70(2):497-499

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Geoheritage values in the Cat Ba islands, Vietnam     

Ta Hoa Phuong  Nguyen Huu Cu  Tran Duc Thanh  Bui Van Dong 《Environmental Earth Sciences》2013,70(2):543-548

Geological wonders have been generally known as natural wonderful products. Resulted from geological processes, geological wonders are diverse in size that have geoheritage values that should be protected from damaging of substance, form and natural development. In a large scale, geological wonders can be geoheritage areas, containing several geodiversity elements that are geologically important or in a smaller scale, they can be geosites of heritage values (or geoheritage sites). In the delimitation of areas, having geoheritage values and the establishment of geoparks, the first thing is to recognise them as geosites and geoheritage areas that indicate great geological values. Besides the Ha Long bay, the world natural heritage with its outstanding aesthetic and geological values, the Cat Ba islands are typical and grandeur karst landscapes formed in tropical condition. Based on the geodiversity elements with their own geoheritage values on aesthetics, uniqueness and grandeur in the Cat Ba islands, the authors have recognised three geoheritage areas: the south cape of the Cat Ba embayment, Tung Gau (shelter), and the Lan Ha bay. Sites where Brachiopods, Crinoids and Tetracorals are exposed on the way through the island are considered as palaeontological geosites. The folds of limestone layers in the northern part of Cat Co 3 beach, with typical turbidite structures in carbonate formations are considered as a lithological geosite. The Devonian-Carboniferous boundary near the Cat Co 3 beach is regarded as a stratigraphical geosite while Que Kem and Turtle islands, etc. are considered as geomorphological geosites.  相似文献   

卫星资料在台风暴雨数值模拟中的应用   总被引：21，自引：4，他引：21  

江敦春  党人庆  陈联寿 《热带气象学报》1994,10(4):318-324

用ＰＳＵ／ＮＣＡＲ中尺度模式，采用ＥＣＭＷＦ资料对８２０９号台风带来的暴雨进行了控制试验，同时采用卫星和地面资料对原有初始湿度场作订正，进行了灵敏试验。对比分析表明，应用卫星资料后，模拟的台风暴雨及雨量中心强度与实况甚为一致。此外，由模式输出流场的分析表明，台风内部及其外围有显著的非对称气流和明显的中尺度系统结构。暴雨发生在低空非对称气流聚合和高空非对称气流辐散重叠区域；在强雨量中心区，低空有清楚  相似文献   

Multi-hazard assessment using machine learning and remote sensing in the North Central region of Vietnam     

Huu Duy Nguyen  Dinh-Kha Dang  Quang-Thanh Bui  Alexandru-Ionut Petrisor 《Transactions in GIS》2023,27(5):1614-1640

Natural hazards constitute a diverse category and are unevenly distributed in time and space. This hinders predictive efforts, leading to significant impacts on human life and economies. Multi-hazard prediction is vital for any natural hazard risk management plan. The main objective of this study was the development of a multi-hazard susceptibility mapping framework, by combining two natural hazards—flooding and landslides—in the North Central region of Vietnam. This was accomplished using support vector machines, random forest, and AdaBoost. The input data consisted of 4591 flood points, 1315 landslide points, and 13 conditioning factors, split into training (70%), and testing (30%) datasets. The accuracy of the models' predictions was evaluated using the statistical indices root mean square error, area under curve (AUC), mean absolute error, and coefficient of determination. All proposed models were good at predicting multi-hazard susceptibility, with AUC values over 0.95. Among them, the AUC value for the support vector machine model was 0.98 and 0.99 for landslide and flood, respectively. For the random forest model, these values were 0.98 and 0.98, and for AdaBoost, they were 0.99 and 0.99. The multi-hazard maps were built by combining the landslide and flood susceptibility maps. The results showed that approximately 60% of the study area was affected by landslides, 30% by flood, and 8% by both hazards. These results illustrate how North Central is one of the regions of Vietnam that is most severely affected by natural hazards, particularly flooding, and landslides. The proposed models adapt to evaluate multi-hazard susceptibility at different scales, although expert intervention is also required, to optimize the algorithms. Multi-hazard maps can provide a valuable point of reference for decision makers in sustainable land-use planning and infrastructure development in regions faced with multiple hazards, and to prevent and reduce more effectively the frequency of floods and landslides and their damage to human life and property.  相似文献   

Application of an analytical hierarchical process approach for landslide susceptibility mapping in A Luoi district,Thua Thien Hue Province,Vietnam   总被引：6，自引：2，他引：4  

Long Nguyen Thanh  Florimond De Smedt 《Environmental Earth Sciences》2012,66(7):1739-1752

A Luoi is a Vietnamese–Laotian border district situated in the western part of Thua Thien Hue province, central Vietnam, where landslides occur frequently and seriously affect local living conditions. This study focuses on the spatial analysis of landslide susceptibility in this 263-km² area. To analyze landslide manifestation in the study area, causative factor maps are derived of slope angle, weathering, land use, geomorphology, fault density, geology, drainage distance, elevation, and precipitation. The analytical hierarchical process approach is used to combine these maps for landslide susceptibility mapping. A landslide susceptibility zonation map with four landslide susceptibility classes, i.e. low, moderate, high, and very high susceptibility for landsliding, is derived based on the correspondence with an inventory of observed landslides. The final map indicates that about 37% of the area is very highly susceptible for landsliding and about 22% is highly susceptible, which means that more than half of the area should be considered prone to landsliding.  相似文献   

Inspirations from the scientific discovery of the anammox bacteria: A classic example of how scientific principles can guide discovery and development     

HongYue Dang  RongFang Huang  NianZhi Jiao 《中国科学:地球科学(英文版)》2016,59(3):449-455

Anaerobic ammonium oxidation(anammox) is a relatively new pathway within the N cycle discovered in the late 1990 s. This eminent discovery not only modified the classical theory of biological metabolism and matter cycling, but also profoundly influenced our understanding of the energy sources for life. A new member of chemolithoautotrophic microorganisms capable of carbon fixation was found in the vast deep dark ocean. If the discovery of the chemosynthetic ecosystems in the deep-sea hydrothermal vent environments once challenged the old dogma "all living things depend on the sun for growth," the discovery of anammox bacteria that are widespread in anoxic environments fortifies the victory over this dogma. Anammox bacteria catalyze the oxidization of NH_4~+ by using NO_2~- as the terminal electron acceptor to produce N_2. Similar to the denitrifying microorganisms, anammox bacteria play a biogeochemical role of inorganic N removal from the environment. However, unlike heterotrophic denitrifying bacteria, anammox bacteria are chemolithoautotrophs that can generate transmembrane proton motive force, synthesize ATP molecules and further carry out CO_2 fixation through metabolic energy harvested from the anammox process. Although anammox bacteria and the subsequently found ammonia-oxidizing archaea(AOA), another very important group of N cycling microorganisms are both chemolithoautotrophs, AOA use ammonia rather than ammonium as the electron donor and O_2 as the terminal electron acceptor in their energy metabolism. Therefore, the ecological process of AOA mainly takes place in oxic seawater and sediments, while anammox bacteria are widely distributed in anoxic water and sediments, and even in some typical extreme marine environments such as the deep-sea hydrothermal vents and methane seeps. Studies have shown that the anammox process may be responsible for 30%–70% N_2 production in the ocean. In environmental engineering related to nitrogenous wastewater treatment, anammox provides a new technology with low energy consumption, low cost, and high efficiency that can achieve energy saving and emission reduction. However, the discovery of anammox bacteria is actually a hard-won achievement. Early in the 1960 s, the possibility of the anammox biogeochemical process was predicted to exist according to some marine geochemical data. Then in the 1970 s, the existence of anammox bacteria was further predicted via chemical reaction thermodynamic calculations. However, these microorganisms were not found in subsequent decades. What hindered the discovery of anammox bacteria, an important N cycling microbial group widespread in hypoxic and anoxic environments? What are the factors that finally led to their discovery? What are the inspirations that the analyses of these questions can bring to scientific research? This review article will analyze and elucidate the above questions by presenting the fundamental physiological and ecological characteristics of the marine anammox bacteria and the principles of scientific research.  相似文献   

Approximate Formula of Peak Frequency of H/V Ratio Curve in Multilayered Model and Its Use in H/V Ratio Technique     

Tran Thanh Tuan  Pham Chi Vinh  P. Malischewsky  Abdelkrim Aoudia 《Pure and Applied Geophysics》2016,173(2):487-498

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Removal of Cr(VI) from Aqueous Solutions Using Buckwheat (Fagopyrum esculentum Moench) Hull through Adsorption–Reduction: Affecting Factors,Isotherm, and Mechanisms          下载免费PDF全文

Kebin Li  Yanhui Zhang  Yan Dang  Hong Wei  Qiquan Wang 《洁净——土壤、空气、水》2014,42(11):1549-1557

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Synoptic-scale physical mechanisms associated with the Mei-yu front: A numerical case study in 1999     

Nguyen Minh Truong  Vu Thanh Hang  Roger A. Pielke Sr.  Christopher L. Castro  Koji Dairaku 《Asia-Pacific Journal of Atmospheric Sciences》2012,48(4):433-448

The Mei-yu front system occurring from 23 to 27 June 1999 consists of the Mei-yu front and the dewpoint front, which confine a warm core extending from the eastern flank of the Tibetan Plateau to the west of 145°E. To further understand the synopticscale physical mechanisms associated with the Mei-yu front system, the present study proposes another insight into the physical significance of the x-component relative vorticity (XRV) whose vertical circulation is expected to tilt isentropic surfaces. The XRV equation diagnoses exhibit that the twisting effect of the planetary vorticity (TEPV) is positive along the Mei-yu front and negative in the dewpoint front region, and tilts isentropic surfaces from south to north in the Mei-yu frontal zone. Conversely, the meridional gradient of the atmospheric buoyancy (MGAB) tilts isentropic surfaces in the opposite direction and maintains negative in the regions where the TEPV is positive and vice versa. Thus, the TEPV plays the role of the Mei-yu frontogenesis, whereas the MGAB demonstrates the Meiyu frontolysis factor. Both terms control the evolution of the cross-front circulation. The other terms show much minor contributions in this case study. The present simulations also indicate that the weakening of the upper-level jet evidently induces the weakening of the Mei-yu front and reduces the amplitude of the East Asia cold trough. Furthermore, the impact can also penetrate into the lower troposphere in terms of mesoscale disturbances and precipitation, proving that the upper-level jet imposes a noticeable top-down influence on the Mei-yu front system.  相似文献   

《工程测量学》双语教学的实践与评估   总被引：2，自引：0，他引：2  

尹晖  罗档 《测绘工程》2006,15(3):74-76,78

介绍工程测量学双语教学的具体实践过程,对工程测量学双语教学模式及教学效果进行了问卷调查、评估与分析,提出工程测量学双语教学存在的问题和应采取的改进措施。  相似文献