A GIS-based glacier inventory for the Antarctic Peninsula and the South Shetland Islands —A first case study on King George Island     

Matthias Braun  F. Rau  Jefferson Simões 《地球空间信息科学学报》2013,16(2):15-24

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)” headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery. This data set will form a first digital baseline study for future glacier monitoring. The presented GIS-based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula. In the database of the glacier inventory topographic information, specific glaciological parameters as well as metadata will be included. The topographic data consists of drainage basin limits, basin areas, altitudinal ranges, perimeters and mean lengths. Glaciological data sets should comprise information on glacier retreat in different periods, glacier velocities, ice thickness and bedrock topography as well as derived parameters. Modelled and measured mass balance parameters could be included as additional data layers. In particular, these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS). Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications, but also other environmental studies on the island will benefit from this standardised remote sensing data sets. Therefore, a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms. Finally, better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950's onward.  相似文献   

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs     

Alistair Raymond Bryce Soutter  René Mõttus 《Chemie der Erde / Geochemistry》2012

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.  相似文献   

Drinking water production from surface water sources in the tropics: Brasília DF,Brazil     

Ekaterina Vasyukova  Wolfgang Uhl  Fuad Braga  Claudia Simões  Tânia Baylão  Klaus Neder 《Environmental Earth Sciences》2012,65(5):1587-1599

Drinking water production at three waterworks was evaluated with respect to variable weather conditions in the Brasília Distrito Federal. Results of the investigation revealed that seasonal variations in rainfall play an important role in influencing the quality of the surface water sources used for drinking water production in the district. In most surface sources, particles and apparent colour are likely to originate from erosion during rain events. This represents the primary challenge facing waterworks, notably when the raw water qualities of the sources to be treated at one facility differ by one order of magnitude, as well significantly varying from one season to the next. Treatment efficiencies in terms of turbidity, apparent colour and dissolved organic carbon (DOC) removal were evaluated. Drinking water quality was found to be significantly influenced by raw water quality at all considered treatment plants. With regard to DOC removal, treatment was most efficient in waterworks which treated raw water with high percentages of biopolymers and humics. Most dissolved organics were removed by coagulation. Finally, conclusions are drawn on how to better cope with challenges facing drinking water production in a tropical climate. The first of these recommendations is the introduction of online turbidity and dissolved organic matter monitoring in order to optimise the coagulation process for the removal of these two parameters. A combination of different coagulants could also be considered for this process. Additional more sophisticated improvements to process stability, such as determination of floc characteristics, introduction of artificial neural networks or the eventual upgrade of the treatment train using membrane filtration, are also suggested.  相似文献   

Response of single benthic metrics and multi-metric methods to anthropogenic pressure gradients, in five distinct European coastal and transitional ecosystems   总被引：4，自引：0，他引：4  

Borja A  Barbone E  Basset A  Borgersen G  Brkljacic M  Elliott M  Garmendia JM  Marques JC  Mazik K  Muxika I  Magalhães Neto J  Norling K  Rodríguez JG  Rosati I  Rygg B  Teixeira H  Trayanova A 《Marine pollution bulletin》2011,62(3):499-513

In recent times many benthic indices have been proposed to assess the ecological quality of marine waters worldwide. In this study we compared single metrics and multi-metric methods to assess coastal and transitional benthic status along human pressure gradients in five distinct environments across Europe: Varna bay and lake (Bulgaria), Lesina lagoon (Italy), Mondego estuary (Portugal), Basque coast (Spain) and Oslofjord (Norway). Hence, 13 single metrics (abundance, number of taxa, and several diversity and sensitivity indices) and eight of the most common indices used within the European Water Framework Directive (WFD) for benthic assessment were selected: index of size spectra (ISS), Benthic assessment tool (BAT), Norwegian quality index (NQI), Multivariate AMBI (M-AMBI), Benthic quality index (BQI), (Benthic ecosystem quality index (BEQI), Benthic index based on taxonomic sufficiency (BITS), and infaunal quality index (IQI). Within each system, sampling sites were ordered in an increasing pressure gradient according to a preliminary classification based on professional judgement. The different indices are largely consistent in their response to pressure gradient, except in some particular cases (i.e. BITS, in all cases, or ISS when a low number of individuals is present). Inconsistencies between indicator responses were most pronounced in transitional waters (i.e. IQI, BEQI), highlighting the difficulties of the generic application of indicators to all marine, estuarine and lagoonal environments. However, some of the single (i.e. ecological groups approach, diversity, richness) and multi-metric methods (i.e. BAT, M-AMBI, NQI) were able to detect such gradients both in transitional and coastal environments, being these multi-metric methods more consistent in the detection than single indices. This study highlights the importance of survey design and good reference conditions for some indicators. The agreement observed between different methodologies and their ability to detect quality trends across distinct environments constitutes a promising result for the implementation of the WFD’s monitoring plans. Moreover, these results have management implications, regarding the dangers of misclassification, uncertainty in the assessment, use of conflicting indices, and testing and validation of indices.  相似文献   

A computational study of nonresonant cross-field diffusion of energetic particles due to their interaction with interplanetary magnetic decreases     

E. Costa  E. Echer  M.V. Alves  B.T. Tsurutani  F.J.R. Simões  F.R. Cardoso  G.S. Lakhina 《Journal of Atmospheric and Solar》2011,73(11-12):1405-1409

We present a new method of calculating cross-field diffusion of charged particles due to their interactions with interplanetary magnetic decreases (MDs) in high heliospheric latitudes. We use a geometric model that evaluates perpendicular diffusion to the ambient magnetic field as a function of particle's gyroradius, MD radius, ratio between fields outside and inside the MD, and a random impact parameter. We use Ulysses magnetic field data of 1994 to identify the MDs and get the empirical size and magnetic field decrease distribution functions. We let protons with energies ranging from 100 keV to 2 MeV interact with MDs. The MD characteristics are taken from the observational distribution functions using the Monte Carlo method. Calculations show that the increase in diffusion tends to saturate when particles' gyroradius becomes as large as MD radii, and that particles' gyroradius increases faster than diffusion distance as the energy of the particles is increased.  相似文献   

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs     

Alistair Raymond Bryce Soutter  René Mõttus 《Chemie der Erde / Geochemistry》2011

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.  相似文献   

Effect of the addition of granitic powder to an acidic soil from Galicia (NW Spain) in comparison with lime   总被引：1，自引：1，他引：0  

Benita?Silva  Remigio?ParadeloEmail author  Nuria?Vázquez  Eduardo?García-Rodeja  María?Teresa?Barral 《Environmental Earth Sciences》2013,69(2):429-441

The impact of diffuse pollution, agricultural land use and climate change on the long-term response of subsurface–surface water quality is not well understood, but is a prerequisite for evaluation of water management options. The goal of this study is to model geochemical evolution of water chemistry from the infiltration through soil into the unsaturated zone, transport through bedrocks and granular aquifers to a river in order to identify zones of steep concentration gradients and high dynamics under transient flow conditions. A numerical model was constructed comprising a 2-D 1,500 m × 150 m vertical cross-section of typical sedimentary rock formations, a glacio-fluvial quaternary gravel aquifer in the valley and soil layers. The model coupled saturated/un-saturated flow and reactive transport under steady state and transient conditions. Geochemical interactions, include intra-aqueous kinetic reactions of oxygen with dissolved organic matter, as well as kinetics of carbonate dissolution/precipitation. This model section was chosen to provide insight in to the principal processes and time scales affecting water chemistry along different flow paths. The numerical simulator MIN3P was used, a finite volume program for variably saturated subsurface flow and multi-component reactive transport. The results show that subsurface water residence times range from approximately 2 to 2,000 years. Different zones are to be expected with respect to the development of mineral equilibria; namely, purely atmospherically influenced, as well as open and closed system carbonate dissolution. Short-term responses to daily averaged changes in precipitation, however, are only visible to some extent in the shallower and near-river parts of flow system and solute loads. This can most likely be explained by directional changes in flow paths, indicating that equilibrium geochemical condition predominate at the hillslope scale, i.e. water quality depends on transport pathways rather than on kinetic effects. The extent of reducing conditions is controlled by the presence of organic-rich layers (i.e. peat deposits), the dissolution kinetics of aquifer organic matter and the subsequent mixing with oxygenated water by hydrodynamic dispersion.  相似文献   

Persistent organic pollutants and histological lesions in Mayan catfish Ariopsis assimilis from the Bay of Chetumal, Mexico     

Noreña-Barroso E  Simá-Alvarez R  Gold-Bouchot G  Zapata-Pérez O 《Marine pollution bulletin》2004,48(3-4):263-269

Livers of catfish (Ariopsis assimilis) from the Bay of Chetumal were analyzed for organochlorine compounds and hydrocarbons as part of a study to diagnose the environmental health of the Bay after a catfish mass mortality that occurred in 1996. The presence of histological lesions in several organs of the fish as result of chemical exposure was also evaluated. The concentrations of organic pollutants found in the Bay may be considered high if compared to the levels reported for sites affected by chemical pollution. High prevalences of cellular alteration histopathologies were found in liver, including hepatic tumors. The presence of some lesions may be related statistically to environmental pollution in the Bay, specially with chlorinated compounds.  相似文献   

Organochlorine compounds in sharks from the Brazilian coast     

Claudio Eduardo de Azevedo e Silva  Adriana de Cássia Lima Dias  José Lailson-Brito  Jean Remy Daveé Guimarães 《Marine pollution bulletin》2009,58(2):294-298

  相似文献   

A Burst with Double Radio Spectrum Observed up to 212 GHz     

C. G. Giménez de Castro  G. D. Cristiani  P. J. A. Simões  C. H. Mandrini  E. Correia  P. Kaufmann 《Solar physics》2013,284(2):541-558

We study a solar flare that occurred on 10 September 2002, in active region NOAA 10105, starting around 14:52 UT and lasting approximately 5 minutes in the radio range. The event was classified as M2.9 in X-rays and 1N in Hα. Solar Submillimeter Telescope observations, in addition to microwave data, give a good spectral coverage between 1.415 and 212 GHz. We combine these data with ultraviolet images, hard and soft X-ray observations, and full-disk magnetograms. Images obtained from Ramaty High Energy Solar Spectroscopic Imager data are used to identify the locations of X-ray sources at different energies, and to determine the X-ray spectrum, while ultraviolet images allow us to characterize the coronal flaring region. The magnetic field evolution of the active region is analyzed using Michelson Doppler Imager magnetograms. The burst is detected at all available radio frequencies. X-ray images (between 12 keV and 300 keV) reveal two compact sources. In the 212 GHz data, which are used to estimate the radio-source position, a single compact source is seen, displaced by 25″ from one of the hard X-ray footpoints. We model the radio spectra using two homogeneous sources, and we combine this analysis with that of hard X-rays to understand the dynamics of the accelerated particles. Relativistic particles, observed at radio wavelengths above 50 GHz, have an electron index evolving with the typical soft–hard–soft behavior.  相似文献