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91.
Predicting soil erosion hazard in Lattakia Governorate(W Syria) 总被引:1,自引:0,他引:1
Mohammed Safwan Khallouf Alaa Alshiehabi Omran Bao Pham Quoc Thi Thuy Linh Nguyen Nam Thai Van Tran Anh Duong Harsányi Endre 《国际泥沙研究》2021,36(2):207-220
The main objective of this study is to predict soil erosion in the Lattakia Governorate(WSyria)using the Water Erosion Prediction Project model(WEPP)and to compare the result with that of the RUSLE.Field survey and data collection were carried out,and 44 soil samples were analyzed.In addition,all the necessary input files were prepared for use in the WEPP model and RUSLE.Results show that more than of 80%of the locations studied experience slight to moderate erosion(less than 5 t/ha/y),whereas the rest of the locations experience severe soil erosion hazard.Moreover,the volume of runoff estimated by the WEPP model is in the range of 51e321 mm,and the R^2 between the simulated soil erosion and the predicted runoff reached 0.68.Interestingly,the R^2 between the WEPP model and RUSLE is 0.56,which indicates a good correlation between the two models. 相似文献
92.
Ngoc Thach Nguyen Ngoc Hai Pham Xuan Canh Pham Thi Thuy Hang Nguyen Van Lam Nguyen Thi Thanh Thuy Duong 《Environmental Earth Sciences》2013,70(2):531-542
Ha Giang is one of the largest, northern border provinces of Vietnam, consisting of four districts: Yen Minh, Quan Ba, Dong Van and Meo Vac. This province features varied karst landscape of Carboniferous–Permian limestone. The region has been recognized by UNESCO as one of the 77 geological parks in the world and the second in Southeast Asia on 3 October 2012. In the dry season, little or no rain is recorded; therefore, surface water is very scarce. For this reason, proper delineation and exploitation of the groundwater resource is critical for sustainable water supply. This has been identified as an important challenge under the scientific project KC-08-10 in the national program KC-08. Remote sensing and GIS were used to decipher the signature of karst water in the highland of Ha Giang. Information layers generated were subjected to multi-criteria evaluation using analytic hierarchy process for decision making to identify ideal locations for groundwater prospecting. The study resulted in delineation of ten zones for all regions and 18 ideal drilling sites in Tam Son Town of Quan Ba District. Drilling and resistivity soundings were performed to assess the success of the interpretation. Deep resistivity survey confirmed low resistivity (200–300 Ωm) near the identified potential sites in Tam Son Town of Quan Ba District. Further, successful drilling at site LKTS1 with a discharge of 7–9 l/s is observed, proving the potential of this methodology for rapid exploration of groundwater in water-scare karst terrains of Vietnam. 相似文献
93.
This study employed image enhancement for LANDSAT TM and ALOS imagery to monitor the changing status of coastal resources from 2001 to 2011, object-based classification of high-resolution THEOS imagery to extract fish cage culture sites and interpolation methods to determine marine environmental quality in 2011 in the northern part of Phu Quoc Island. There were five classes in the study site: natural forest, Melaleuca forest, agriculture, peat and built-up areas. Agricultural land and Melaleuca forest changing into built-up areas constituted approximately 51.13% of the total area changing. The benthic seagrass habitat increased dramatically from 2001 to the end of 2010. Besides, marine culture has been concerned to cage culture which is one of the sources directly affecting aquatic life and water quality in coastal environment. Cage culture locations were detected using high-resolution imagery as THEOS data for image fusion and Object-based Image Analysis methods. Water quality criteria including nitrogen, phosphorus and chlorophyll-a concentrations were determined by interpolation method, and the spatial distribution of these parameters showed a concentration in the study area in the range from 0.17 to 0.49?mg/L, 0.012 to 0.073?mg/L and 0.26 to 1.046?μg/L, respectively. 相似文献
94.
Navarro P Amouroux D Thanh ND Rochelle-Newall E Ouillon S Arfi R Van TC Mari X Torréton JP 《Marine pollution bulletin》2012,64(9):1789-1798
In this work, two field campaigns were performed in July 2008 (wet season) and March 2009 (dry season) to produce original data on the concentration, partition and distribution of mercury and butyltin compounds along the tropical Bach Dang Estuary located in North Vietnam (Haiphong, Red River Delta). The results demonstrate that mercury and butyltin speciation in the surface waters of this type of tropical estuary is greatly affected by the drastic changes in the seasonal conditions. During high river discharge in the wet season, there was a large estuarine input of total Hg and tributyltin, while the longer residence time of the waters during the dry season promotes increasing MMHg formation and TBT degradation. Although most of the Hg and TBT is transported into the estuary from upstream sources, tidal cycle measurements demonstrate that this estuary is a significant source of TBT and MMHg during the wet (~3kgTBT/day) and dry (~3gMMHg/day) seasons. 相似文献
95.
P. Ehrenfreund E.F. Van Dishoeck M. Burgdorf J. Cami P. Van Hoof A.G.G.M. Tielens W.A. Schutte W.F. Thi 《Astrophysics and Space Science》1997,255(1-2):83-89
We present ISO observations of bright, high-mass southern starforming regions with the Short Wavelength Spectrometer (SWS)
and Long Wavelength Spectrometer (LWS). The selected targets show a range of pre-main sequence evolutionary phases. Whereas
some objects still show interstellar ice features, the most evolved objects are coincident with ultra-compact HII regions
and show strong emission lines from atomic species and polycyclic aromatic hydrocarbons (PAHs). We discuss the ISO spectra
between 2.5 - 200 μm of selected southern star-forming regions in the context of their evolution.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
96.
Nguyen Ngoc Thuy 《中国地震研究》2002,16(3):268-270
In this paper,a historical review of the seismic network of Vietnam and the ability of the network to monitor earthquakes is presented.The seismic activity of Vietnam as a country of high seismictiy in the last century and since the beginning of the new century is described.The current state of seismological research in Vietnam and cooperation with institutions outside of Vietnam is outlined. 相似文献
97.
The X-ray fluorescence analysis is an important means for the determination of the heavy metal concentrations in sewage sludges and for the evaluation of their usability in agriculture. Analysis devices from the GDR were used for that. For the investigations there was used as the zero sample a sludge which was not loaded with heavy metals, homogeneous and constantly dried at 105 °C. The drying bed sludge samples were treated with different heavy metal solutions with different concentrations. Preparation of samples, measuring conditions and general spectra are described. The measuring results of tests up to 100 g heavy metal in 1 kg dry substance are critically evaluated. The analysis of a sewer sludge sample takes only about ten minutes. There are determined: Cr, Ni, Cu, Zn, Mo, Cd, Hg and Pb. 相似文献
98.
So far,Artemia populations in solar saltponds of southern France have been considered as belonging to the Old World parthenogenetic strain.
However, two populations sampled monthly in abandoned salinas of Sète-Villeroy and Villeneuve appear to be bisexual throughout
their life-cycle. Their sex ratio regularly fluctuates near equilibrium, and mating, present throughout life, is very common
in early winter. Morphological characteristics, particularly the male frontal knobs structure, are discussed in relation to
the diploid bisexual Mediterranean strain,Artemia tunisiana, which is distributed around the Mediterranean basin. The existence of sexual populations is discussed in regard to variation
in environmental conditions in abandoned salinas. 相似文献
99.
Thuy Le Toan Shaun Quegan Ian Woodward Mark Lomas Nicolas Delbart Ghislain Picard 《Climatic change》2004,67(2):379-402
This paper addresses the use of radar remote sensing to map forest above-ground biomass, and discusses the use of biomass maps to test a dynamic vegetation model that identifies carbon sources and sinks and predicts their variation over time. For current radar satellite data, only the biomass of young/sparse forests or regrowth after disturbances can be recovered. An example from central Siberia illustrates that biomass can be measured by radar at a continental scale, and that a significant proportion of the Siberian forests have biomass values less than 50 tonnes/ha. Comparison between the radar map and calculations by the Sheffield Dynamic Global Vegetation Model (SDGVM) indicates that the model considerably overestimates biomass; under-representation of managed areas, disturbed areas and areas of low site quality in the model are suggested reasons for this effect. A case study carried out at the Büdingen plantation forest in Germany supports the argument that inadequate representations of site quality and forest management may cause model overestimates of biomass. Comparison of the calculated biomass of stands planted after 1990 with biomass estimates by radar allows identification of forest stands where the growth conditions assumed by the model are not valid. This allows a quality check on model calculations of carbon fluxes: only calculations for stands where there is good agreement between the data and the model predictions should be accepted. Although the paper only uses the SDGVM model, similar effects are likely in other dynamic vegetation models, and the results show that model calculations attempting to quantify the role of forests as carbon sources or sinks could be qualified and potentially improved by exploiting remotely sensed measurements of biomass. 相似文献
100.
Dealing with Compositional Data: The Freeware CoDaPack 总被引:2,自引:0,他引:2