Glacier recession and human vulnerability in the Yanamarey watershed of the Cordillera Blanca, Peru   总被引：2，自引：0，他引：2  

Jeffrey T. Bury  Bryan G. Mark  Jeffrey M. McKenzie  Adam French  Michel Baraer  Kyung In Huh  Marco Alfonso Zapata Luyo  Ricardo Jes��s G��mez L��pez 《Climatic change》2011,105(1-2):179-206

Glaciers in the Cordillera Blanca, Peru, are undergoing rapid retreat, in large part due to climate change. These changes are significantly altering water availability in the region and pose critical risks to local populations that are highly dependent on these resources for livelihoods. We examine these issues through an interdisciplinary and linked evaluation of hydrological change and livelihood vulnerability in the Yanamarey watershed. Physical observations of the Yanamarey glacier show acceleration in frontal retreat at a rate of 8 m decade^???1 since 1970, accompanied by total volume loss on the order of 0.022 km³. Hydrological and hydrochemical analyses document a possible transformation of stream flow over the past decade as the seasonal storage capacity of the glacier has degraded. Recent stream discharge measurements from the proglacial lake below the glacier are more coincident with the highly variable seasonal precipitation than they were during the 1998?C1999 hydrological year. Local household perceptions of glacier recession and seasonal hydrological variability agree with this trend, which is increasing human vulnerability in the watershed. Household case-study survey results demonstrate that shifting water resources, increasing weather extremes and climate-related threats to tourism are all new vectors of vulnerability for household livelihoods.  相似文献   

Ecological quality assessment of small estuaries from the Portuguese coast based on fish assemblages indices     

Cardoso I  Pais MP  Henriques S  da Fonseca LC  Cabral HN 《Marine pollution bulletin》2011,62(5):992-1001

The importance of establishing the ecological quality of estuarine systems has been widely acknowledged and led to the development of several fish community-based multimetric indices. Nevertheless, a question rose about the accuracy of these tools when natural disturbance is acting upon the organization of the systems’ communities. Four multimetric indices were used to examine their ability to differentiate the ecological status of five small estuarine systems (southern Portugal), and also to test if they reflected the level of anthropogenic pressures. Fish assemblages from Mira, Odeceixe and Aljezur (in the Southwest coast), Gilão and Bensafrim (in the South coast) estuaries were sampled seasonally for one year, and anthropogenic sources of pressure were identified and quantified. We found that although the applied indices provided information on ecological condition differentiation among systems, they are unable to explain different classes of ecological status in systems with equivalent pressure levels.  相似文献   

Use of daily precipitation uncertainties in streamflow simulation and forecast   总被引：3，自引：2，他引：1  

Yeonsang Hwang  Martyn P. Clark  Balaji Rajagopalan 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(7):957-972

Among other sources of uncertainties in hydrologic modeling, input uncertainty due to a sparse station network was tested. The authors tested impact of uncertainty in daily precipitation on streamflow forecasts. In order to test the impact, a distributed hydrologic model (PRMS, Precipitation Runoff Modeling System) was used in two hydrologically different basins (Animas basin at Durango, Colorado and Alapaha basin at Statenville, Georgia) to generate ensemble streamflows. The uncertainty in model inputs was characterized using ensembles of daily precipitation, which were designed to preserve spatial and temporal correlations in the precipitation observations. Generated ensemble flows in the two test basins clearly showed fundamental differences in the impact of input uncertainty. The flow ensemble showed wider range in Alapaha basin than the Animas basin. The wider range of streamflow ensembles in Alapaha basin was caused by both greater spatial variance in precipitation and shorter time lags between rainfall and runoff in this rainfall dominated basin. This ensemble streamflow generation framework was also applied to demonstrate example forecasts that could improve traditional ESP (Ensemble Streamflow Prediction) method.  相似文献   

Evidence for significant clockwise rotations of the Korean Peninsula during Cretaceous   总被引：1，自引：0，他引：1  

Youn Soo Lee  Hyun-Chul Han  Jae Ha Hwang  Weon-Seo Kee  Bok Chul Kim 《Gondwana Research》2011,20(4):904-918

In an effort to evaluate the Cretaceous magnetostratigraphy for the Korean Peninsula and to establish the tectonic coherence of its various elements, we collected paleomagnetic data from 121 samples from 20 sites within the Chilgok Formation (108.3–109.9 Ma) in the Gyeongsang Basin. Together with previously published data, we evaluate the results from a total of 163 sites in the basin.We combine our age model with results from recent stratigraphic, paleomagnetic and radiometric geochemical studies. In this study, we found that two distinct declination shifts decrease with younging direction, indicating two clockwise rotational events of the Korean Peninsula with respect to the Eurasia continent. The earlier event took place during 130–100 Ma (Phase I, newly termed “Goguryeo Disturbance”) and a later one during 80–50 Ma (Phase III, belonging to “Bulguksa Orogeny”). The mean rotation rate in the interval from 115.2 to 103.8 Ma (Phase I) is about 0.74°/Ma, while the rate from 90.9 to 79.8 Ma (Phase II) is 0.19°/Ma. Based on paleolatitude change during Phase I, we infer that the Korean Peninsula (eastern part of the Sino-Korea Block) migrated southward about 300 km after the complete amalgamation of the Sino-Korea Block into the Eurasian continent resulting in N–S compression within the Korean peninsula and Manchuria. Large-scale strike-slip faults (e.g., Tan-Lu Fault, Okcheon Boundary Fault) were probably rejuvenated in the Sino-Korea Block during Phase I.  相似文献   

Web-GIS tool for the management of rural land markets     

Juan Porta  Jorge Parapar  Paula García  Gracia Fernández  Juan Touriño  Ramón Doallo  Francisco Ónega  Inés Santé  Pablo Díaz  David Miranda  Rafael Crecente 《Earth Science Informatics》2013,6(4):209-226

Land abandonment and stagnation of rural markets in the last few years have become one of the main concerns of rural administrations. The use of Web and GIS (Geographic Information System) technologies can help to mitigate the effects of these problems. This paper pro-poses a novel Web-GIS tool with spatial capabilities for the dynamization of rural land markets by encouraging the transfer of land from owners to farmers through the leasing of plots. The system, based on open source software, offers information about the properties, their environment and their owners. It uses standards for handling the geographic information and for communicating with external data sources. This system was used as the basis for the development of SITEGAL, the tool for the management of the Land Bank of Galicia (www.bantegal.com/sitegal). SITEGAL has been operational since 2007 obtaining benefits for both administration and users (farmers and land owners), and promoting the e-Government.  相似文献   

Retention studies of chromium (VI) from aqueous solution on the surface of a novel carbonaceous material     

Sajjad Hussain  Saima Gul  Sabir Khan  Habib ur Rehman 《Arabian Journal of Geosciences》2013,6(11):4547-4556

In the present study, the retention capacity of carbonaceous material obtained from the diesel engine exhaust mufflers for Cr(VI) removal has been investigated. The physicochemical properties such as density, pH of aqueous slurry, pH at point of zero charge, ash content, moisture content, volatile matter, surface area, scanning electron microscopy and electron dispersive spectroscopy of the carbonaceous material were determined. The capacity of adsorbent for removal of Cr(VI) from aqueous solution was observed under different experimental condition like contact time, initial concentration of metal ions, pH and temperatures on the adsorption capacity of the adsorbent. Maximum adsorption of Cr(VI) ions was found at low pH. The adsorption process was found to follow second-order kinetics. The rate constant was evaluated at different temperatures along with other thermodynamic parameters like activation energy, Gibbs free energy change, enthalpy change and entropy change. Both Langmuir and Freundlich isotherms were used to describe the adsorption equilibrium of carbonaceous material at different temperatures. Langmuir isotherm shows better fit than Freundlich isotherm at given conditions. The result shows that low-cost carbonaceous material from diesel engine exhaust mufflers can be efficiently used for wastewater treatment containing Cr(VI) ions.  相似文献   

GPS Height and Gravity Variations Due to Ocean Tidal Loading Around Taiwan     

Ta-Kang Yeh  Cheinway Hwang  Guochang Xu 《Surveys in Geophysics》2009,30(1):51-51

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Gravity recovery using COSMIC GPS data: application of orbital perturbation theory   总被引：14，自引：0，他引：14  

C. Hwang 《Journal of Geodesy》2001,75(2-3):117-136

 COSMIC is a joint Taiwan–US mission to study the atmosphere using the Global Positioning System (GPS) occultation technique. Improved formulas are developed for the radial, along-track, and cross-track perturbations, which are more accurate than the commonly used order-zero formulas. The formulas are used to simulate gravity recovery using the geodetic GPS data of COSMIC in the operational phase. Results show that the EGM96 model can be improved up to degree 26 using 1 year of COSMIC data. TOPEX/POSEIDON altimeter data are used to derive a temporal gravity variation. COSMIC cannot reproduce this gravity variation perfectly because of data noise and orbital configuration, but the recovered field clearly shows the gravity signature due to mass movement in an El Ni?o. Received: 3 March 2000 / Accepted: 10 November 2000  相似文献   

Evaluation of the liquid hydrocarbon potential of coal by artificial maturation techniques     

S.C. Teerman  R.J. Hwang 《Organic Geochemistry》1991,17(6)

In certain areas, relatively large accumulations of liquid hydrocarbons have been attributed to coals. Evaluating the source rock potential of coal requires definition of both the generative potential (quantity and composition of generated hydrocarbons), and expulsion efficiency. Hydrous pyrolysis experiments were completed using Tertiary lignites (R_o < 0.35%) from North Dakota and the Far East to evaluate the source rock potential of coal. The North Dakota lignite is vitrinite-rich (93%) and liptinite-poor (3%); the Far East lignite is liptinite-rich (32% of total maceral content). These lignites have Hydrogen Index values of 123 and 483 mg HC/g OC, respectively. Differences in oil-pyrolysate yield, composition, and temperature of maximum pyrolysate yield from hydrous pyrolysis experiments for these two lignites are related to the type and amount of liptinite and vitrinite macerals. A maximum of 48 and 158 mg oil-pyrolysate/g OC is generated and expelled from the North Dakota and Far East lignites, respectively. Although these lignites consist predominantly of gas-prone vitrinitic components, their organic-rich nature can compensate for their poor convertibility to liquid hydrocarbons. The composition of these artificially generated oil-pyrolysates are similar to some non-marine oils, suggesting that this type of organic matter can be a significant contributor to many oils. Although the overall composition of the generated products from the two lignites is similar, the distribution of these products is significantly different. Homologous series of methyl ketones and alkyl benzenes have been identified in both oil-pyrolysates. Their presence and characteristic distribution suggest that microbial degradation occurred during the formation of these lignites. Although many coals generate significate amounts of liquid hydrocarbons that are similar to naturally occurring oils, poor explusion efficiency limits their source rock potential. Significant amounts of liquid products are assimilated by the vitrinitic matrix of most coals prior to expulsion, severely limiting the amount of petroleum available for migration and reservoir accumulation. However, adequate expulsion may occur in certain liptinite-rich coals or coals occurring in unique depositional settings.  相似文献   

Metagenomic characterization of viral communities in Goseong Bay,Korea     

Jinik Hwang  So Yun Park  Mirye Park  Sukchan Lee  Yeonhwa Jo  Won Kyong Cho  Taek-Kyun Lee 《Ocean Science Journal》2016,51(4):599-612

In this study, seawater samples were collected from Goseong Bay, Korea in March 2014 and viral populations were examined by metagenomics assembly. Enrichment of marine viral particles using FeCl₃ followed by next-generation sequencing produced numerous sequences. De novo assembly and BLAST search showed that most of the obtained contigs were unknown sequences and only 0.74% of sequences were associated with known viruses. As a result, 138 viruses, including bacteriophages (87%), viruses infecting algae and others (13%) were identified. The identified 138 viruses were divided into 11 orders, 14 families, 34 genera, and 133 species. The dominant viruses were Pelagibacter phage HTVC010P and Roseobacter phage SIO1. The viruses infecting algae, including the Ostreococcus species, accounted for 9.4% of total identified viruses. In addition, we identified pathogenic herpes viruses infecting fishes and giant viruses infecting parasitic acanthamoeba species. This is a comprehensive study to reveal the viral populations in the Goseong Bay using metagenomics. The information associated with the marine viral community in Goseong Bay, Korea will be useful for comparative analysis in other marine viral communities.  相似文献