Ocean modelling studies in support of altimetry     

Paula Berry  John Marshall 《Dynamics of Atmospheres and Oceans》1989,13(3-4)

Simulation studies are presented that consider the degree to which baroclinic ocean circulation models are constrained by observations of the surface pressure field on space and time-scales possible with future satellite-borne altimeters. Two- and three-layer eddy resolving quasi-geostrophic models are used to simulate and assimilate altimetric observations.For synoptic mapping of the oceanic eddy field on the scale of an ocean basin, a satellite orbit repeat time of 14 days is found to be optimum. Our studies suggest that altimetric observations will provide strong constraints on the surface flow of such models and, if used in conjunction with them, may be used to infer the deep flows.  相似文献   

Increasing public awareness of natural hazards via the Internet     

Paula K. Dunbar 《Natural Hazards》2007,42(3):529-536

NOAA’s National Geophysical Data Center is using state-of-the-art Internet tools for natural hazards education, public outreach, and access to natural hazards data. For example, NGDC acquires, processes, and provides access to geologic hazards event data that are useful in natural hazards risk assessment and hazards-related research. In addition, a collection of natural hazards slides and a teacher’s guide on volcanoes are available online. NGDC also created an online “Kids Hazards Quiz” to test the user’s knowledge of disaster safety information. An online Natural Hazards Data Resources Directory provides access to information and links to organizations that provide natural hazards data and information. Expanded access to these data and information by the public and researchers can increase public awareness of natural hazards, improve hazards research, and ultimately reduce the devastating impacts of natural disasters.  相似文献   

Modelling the effects of cross-sectoral water allocation schemes in Europe     

Florian Wimmer  Eric Audsley  Marcus Malsy  Cristina Savin  Robert Dunford  Paula A. Harrison  Rüdiger Schaldach  Martina Flörke 《Climatic change》2015,128(3-4):229-244

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Patterns of basin fill in Triassic turbidites of the Nanpanjiang basin: implications for regional tectonics and impacts on carbonate‐platform evolution          下载免费PDF全文

Daniel J. Lehrmann  Daniel H. Chaikin  Paul Enos  Marcello Minzoni  Jonathan L. Payne  Meiyi Yu  Alexa Goers  Tanner Wood  Paula Richter  Brian M. Kelley  Xiaowei Li  Yanjiao Qin  Lingyun Liu  Gang Lu 《Basin Research》2015,27(5):587-612

The Nanpanjiang Basin occurs in a key position for resolving controversies of basin tectonics and patterns of plate assembly at the junction between south China and Southeast Asian plates. Paleocurrent measurements indicate that siliciclastic turbidites in the basin were sourced by the Precambrian Jiangnan uplift to the northeast, the Precambrian Yunkai uplift to the southeast and the Triassic Songma suture to the south. Detrital zircon geochronology reveals Archean (2500 Ma), Paleoproterozoic (1800–1900 Ma), Neoproterozoic (900–1000 Ma) and Paleozoic (420–460 Ma) ages consistent with derivation from the Jiangnan and Yunkai uplifts. A large Permian‐Triassic peak of 250 Ma is present in the southern basin and attenuates northward suggesting derivation from an arc developed along the Songma suture. Sandstone QFL compositions average 65/12/23% and plot in the recycled orogen field except for a few samples in the southern basin that fall in the dissected arc field. The compositions are consistent with derivation from Precambrian basement that includes orogenic complexes. In the southern basin, Middle Triassic turbidites contain greater lithics and feldspars and Lower Triassic turbidites have volcaniclastic composition consistent with derivation from a southerly arc. Our preferred interpretation is evolution from remnant basin to a large peripheral foreland with southward subduction and convergence with Indochina along the Songma suture. The previously proposed Dian‐Qiong zone is not a suture as its map location places it within carbonate platforms bounded by identical stratigraphy. The Nan‐Uttaradit zone is too distant to have provided voluminous siliciclastic flux to the basin. The Nanpanjiang Basin provides an example of the evolution of an exceptionally large foreland with far‐field rejuvenation of Precambrian uplifts and carbonate platforms that were significantly influenced by siliciclastic flux. The timing and pattern of turbidite basin fill impacted platform evolution by enabling margin progradation in areas proximal to siliciclastic sources, whereas platforms distant from sources were driven to aggradation and extreme relief with large‐scale gravitational sector collapse.  相似文献   

The Solar Rotation in the 1930s from the Sunspot and Flocculi Catalogs of the Ebro Observatory     

V. de Paula  J. J. Curto  R. Casas 《Solar physics》2016,291(8):2269-2279

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Metagenomic Analysis of Bacterial Communities from a Nitrification–Denitrification Treatment of Landfill Leachates     

Ana Isabel Díaz  Paula Oulego  Adriana Laca  Jos Manuel Gonzlez  Mario Díaz 《洁净——土壤、空气、水》2019,47(11)

The efficiency of the biological removal of carbon and nitrogen from leachates is determined by the activity of microbial populations present in biological reactors. In this work, a complete characterization of bacterial communities revealed by personal genome machine sequencing (PGM) has been carried out from different points of a nitrification–denitrification process operated in an urban landfill. The leachate fed to the treatment is a mixture of young leachate, old leachate, and effluent from an anaerobic digestion process, in a volume ratio of 1:0.9:0.12, respectively. The anoxic and oxic reactors are followed by an ultrafiltration step. Samples are taken from different points of the process. Results reveal the microbial diversity of the samples, which include detection of minority populations that are difficult to explore by other methods. Bacteria belonging to Bacteroidetes and Proteobacteria are dominant in all the samples analyzed. Proteobacteria represents more than 50% of the total population in all cases. Samples taken after the biological treatment show a significant reduction in the relative abundance of Firmicutes, Tenericutes, and Lentisphaerae phyla in comparation with the initial leachate. The relative abundance of the classes is also studied and the most abundant in the samples are β‐Proteobacteria and Flavobacteria.  相似文献   

Combined effects of waves and plants on a mud deposition event at a mudflat-saltmarsh edge in the Bahía Blanca estuary     

Paula D. Pratolongo  Gerardo M.E. Perillo  M. Cintia Piccolo 《Estuarine, Coastal and Shelf Science》2010

This study was carried out at the Bahía Blanca Estuary, Argentina, at the seaward edge of a saltmarsh. The saltmarsh-mudflat boundary in the study area shows sediment deposits at a higher elevation immediately seaward of the saltmarsh edge. We compared field determinations of water velocity, bed shear stress, wind wave conditions and variations of the bed elevation in the mudflat and within the Spartina alterniflora canopy at the seaward edge of a saltmarsh, and we evaluated the relative role of vegetation in the observed morphology. A mud deposition event that raised bed elevation in more than 5 cm occurred during the study period, with TSS concentrations > 500 mg l⁻¹, but simultaneous measurements performed on the bed levels confirmed that the sediments deposited did not originate from local resuspension within the edge of the canopy. In similar tidal cycles in terms of local wave activity and bed shear stresses at the sampling site, deposition occurred only with winds aligned with the azimuth of the Canal Principal, reaching a maximum fetch of more than 20 km in front of the sampling site.  相似文献   

Distribution and vertical dynamics of planktonic communities at Sofala Bank, Mozambique     

M.C. Leal  C. S  S. Nordez  V. Brotas  J. Paula 《Estuarine, Coastal and Shelf Science》2009,84(4):605-616

Coastal ecosystem processes are largely influenced by the interaction of different factors operating at various temporal and spatial scales, specifically those responsible for primary production patterns that modulate zooplankton and subsequent trophic levels. Hydrological processes, such as tidal cycles and coastal currents, nutrients availability, phytoplankton groups (studied through algal pigment signatures analysed by HPLC), and zooplankton abundance and distribution were investigated at the Sofala Bank (Mozambique), with special emphasis on their horizontal distribution and vertical dynamics (48 h). Horizontal distribution has shown inshore–offshore gradients in all analysed parameters, as well as inshore waters intrusion probably related to Zambezi River delta runoff. Tidal currents were responsible for major hydrological vertical variations and for horizontal and vertical advection of phytoplankton biomass in the surface and deepest layers, respectively. Nutrient concentrations were typical from oligotrophic regions, and nutrient ratios were strongly influenced by depleted nitrate + nitrite concentrations, indicating low estuarine discharges typical from the dry season. The very low N:P ratio obtained suggests strong nitrogen limitation to phytoplankton communities, supporting the low phytoplankton abundance observed. Both phytoplankton pigments and zooplankton were found mainly near the bottom (40 m depth), despite the latter displayed vertical migrations triggered by light variations. Phytoplankton community was dominated by microflagellates, specifically prymnesiophyceans, and behaved as a whole, except Cyanobacteria that displayed vertical distribution movements different from other phytoplankton groups, being mainly concentrated at mid-water column depths (10–20 m). This investigation enhances physico-chemical phenomena and their importance determining the planktonic communities vertical dynamics at Sofala Bank, a tropical coastal ecosystem of the Western Indian Ocean where planktonic dynamics are still poorly described and understood.  相似文献   

Small-scale fisheries and food security strategies in countries in the Benguela Current Large Marine Ecosystem (BCLME) region: Angola,Namibia and South Africa     

Merle Sowman  Paula Cardoso 《Marine Policy》2010

This paper provides an overview of the small-scale fisheries sector in countries within the Benguela Current Large Marine Ecosystem (BCLME), one of the most productive large marine ecosystems in the world. The study revealed that Angola, Namibia and South Africa have very different legal and policy frameworks, show different levels of compliance with international and regional agreements to protect the livelihoods and food security of small-scale fishers, as well as of integration of fisheries into food security objectives. Angolan law recognises and protects small-scale fishers through legal and institutional mechanisms. In Namibia, this sector of fishers is not legally recognised, while in South Africa traditional fishers have been largely excluded from the new fisheries management framework. Trends in national and regional fish consumption and in the extent of export orientation in fisheries are explored, as well as the potential threats to small-scale producers and food security in the region posed by ongoing drives to incorporate fisheries in the World Trade Organisation (WTO) agreements.  相似文献   

Effects of naphthalene and phenanthrene on visual and prey capture endpoints during early stages of the dourado Salminus brasiliensis     

Carvalho PS  Kalil Dda C  Novelli GA  Bainy AC  Fraga AP 《Marine environmental research》2008,66(1):205-207

Naphthalene (NAP) and phenanthrene (PHE) effects on Salminus brasiliensis, a carnivorous freshwater fish, were investigated using behavioral tests. Larval stages of S. brasiliensis were exposed to water concentrations of 0, 0.04 mg/l, 0.20mg/l and 0.50mg/l for naphthalene and 0, 0.01 mg/l, 0.05 mg/l and 0.1mg/l for phenanthrene during two developmental phases. The prey fish Prochilodus lineatus were not exposed. Visual acuity was measured at the end of phase 2 in individual S. brasiliensis, which were also tested at the end of each phase for number of attacks on prey, number of prey captured, prey capture efficiency, and distance swam. Vision was impaired by PHE exposure, as acuity angles increased in exposed fish. At Stage I 2.3+/-1.2 prey were captured with 46% efficiency in controls compared to 0.4+/-0.3 prey captured with 13.4% efficiency in fish exposed to 0.05 mg PHEl(-1), the LOEL for both endpoints. At Stage II 4.0+/-1.1 preys were captured in controls compared to 2.5+/-0.9 preys captured in fish exposed to 0.01 mg PHEl(-1), the LOEL. Stage II control fish captured prey with 70% efficiency compared to 30% efficiency at Stage II fish exposed to 0.05 mg PHEl(-1), the LOEL. Distance swam was not affected by either NAP or PHE exposure. The exposure of larval stages of S. brasiliensis to realistic water concentrations of PHE impairs foraging skills and could affect recruitment of the species.  相似文献