Predicting site-specific storm wave run-up     

Fiedler  Julia W.  Young  Adam P.  Ludka  Bonnie C.  O’Reilly  William C.  Henderson  Cassandra  Merrifield  Mark A.  Guza  R. T. 《Natural Hazards》2020,104(1):493-517

Natural Hazards - Storm wave run-up causes beach erosion, wave overtopping, and street flooding. Extreme runup estimates may be improved, relative to predictions from general empirical formulae...  相似文献   

Balance of S in a constructed wetland built to treat acid mine drainage, Idaho Springs, Colorado, U.S.A.     

Steven D. Machemer  Julia S. Reynolds  Leslie S. Laudon  Thomas R. Wildeman 《Applied Geochemistry》1993,8(6)

The wetland constructed at the Big Five Tunnel in Idaho Springs, Colorado was designed to remove, passively, heavy metals from acid mine drainage. In optimizing the design of such a wetland, an improved understanding of the chemical processes operating there was required, particularly SO₄²⁻ reduction and sulfide precipitation. For this purpose, field and laboratory data were collected to study the balance of S in the system. Field data collected included water analyses of the mine drainage and wetland effluents and measurements of H₂S gas emissions from the wetland. The concentration of sulfide in the wetland effluent ranged from 10⁻⁴ to 10⁻³ mol/l. The average rates of H₂S emission from the surface of the substrate were 150 nmol/cm²/d in the summer and 0.17 and 0.35 nmol/cm²/d in the winter. This maximum estimated loss of sulfide was not significant in reducing the amount of sulfide available for precipitation with metals. Sequential extraction experiments for S on wetland substrates showed that acid volatile sulfides (AVS) increased with time in the wetland substrate. A serum bottle experiment was conducted to study the S balance in the Big Five wetland by quantitatively measuring the amount of S in different phases as microbial SO₄²⁻ reduction progressed. The increase in AVS reasonably balanced the decrease in SO₄²⁻ concentration in the experiment, suggesting that the decrease in SO₄²⁻ concentration represented the amount of SO₄²⁻ reduced and that nearly all of the sulfide produced was precipitated as AVS. Sulfide precipitation was determined to be the primary metal removal process in the wetland system and amorphous FeS is the primary iron sulfide formed in the substrate.  相似文献   

An Ecosystem Based Fisheries Management framework: the efficient,regional-level planning tool for management agencies     

W.J. Fletcher  J. Shaw  S.J. Metcalf  D.J. Gaughan 《Marine Policy》2010

The value of applying a regional level, Ecosystem Based Fisheries Management (EBFM) framework, which is a step-wise, hierarchical, risk-based approach, was tested on the West Coast Bioregion of Western Australia. With structured stakeholder input, over 600 ecological, social, economic and governance issues were initially identified for the region. This complexity was reduced to a level useful for management by consolidating the individual risks into 60 regional-level risks, with a multi-criteria analysis used to integrate the ecological, social and economic risks into just 24 Departmental-level priorities, which ranged from very low to urgent. Given this success, EBFM-based priorities now form the basis for the Department’s budget planning process, plus the framework is providing a critical link between fishery level issues and the broader processes undertaken by other marine based agencies. The EBFM framework is a significant step forward for the integrated management of natural resources by enabling all assets and issues relevant to stakeholders and government to be holistically considered at a regional level.  相似文献   

New sedimentological and palynological data from the Yarkand-Fergana Basin(Kyrgyz Tian Shan): Insights on its Mesozoic paleogeographic and tectonic evolution     

Julien Morin  Marc Jolivet  Dave Shaw  Sylvie Bourquin  Elena Bataleva 《地学前缘(英文版)》2021,12(1):183-202

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The Australian continental shelf: Has Australia's high-latitude diplomacy paid off?’     

Julia Jabour 《Marine Policy》2009

The Commission on the Limits of the Continental Shelf has granted Australia extended continental shelf areas around two of its sub-Antarctic island groups, and these extend into the Antarctic Treaty area. The overlap potentially raises conflict between Australian and Antarctic interests. Australia's submission included and expressly excluded Antarctic data and its high-latitude diplomacy paid off, but its next steps will be crucial to gaining acceptance by other Antarctic Treaty parties. It is likely that any resource exploitation will stop at the fence (60° South) during the life of the Treaty.  相似文献   

Igneous cooling history of olivine‐phyric shergottite Yamato 980459 constrained by dynamic crystallization experiments          下载免费PDF全文

Emily First  Julia Hammer 《Meteoritics & planetary science》2016,51(7):1233-1255

Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine‐phyric shergottite Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h^?1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h^?1, consistent with crystallization within a lava flow at depths of 25–45 cm. Increased cooling rate (~100 °C h^?1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5–7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe‐like flow and subsequent breakout on the surface of Mars.  相似文献   

Holocene landscape reconstruction in the surroundings of the Temple of Pepi I at ancient Bubastis,southeastern Nile Delta (Egypt)     

Philipp Garbe  Amr Abd El-Raouf  Ashraf Es-Senussi  Eva Lange-Athinodorou  Julia Meister 《Geoarchaeology》2024,39(1):17-34

In ancient Egypt, lakes, canals, and other water bodies were an essential part of the sacred landscape in which temples were embedded. In recent years, geoarchaeological research at the site of the Temple of Bastet at Bubastis in the southeastern Nile Delta has proven the existence of two water canals surrounding the temple. It has now been investigated whether these canals were connected to the Temple of Pepi I (2300–2250 B.C.E.), located approximately 100 m to the west of the Temple of Bastet. To explore the Holocene landscape genesis of the Temple of Pepi I, 15 drillings and six geoelectrical profile lines were performed in the surroundings of the temple in spring 2022. The results show loamy to clayey sediments in deeper sections of all drillings with a maximum thickness of 1.70 m, indicating a marshy or swampy depositional environment. Based on the recovered sediment sequences and archaeological remains in the vicinity of the Temple of Pepi I, the marshy or swampy area existed before the Fourth Dynasty. During the Old Kingdom (ca. 2850–2180 B.C.E.), the former marshland either dried up through natural processes or was intentionally drained and filled with sediments for subsequent use for occupation. Regarding the original research question, there is as yet no evidence for a direct connection to the canals of the Temple of Bastet.  相似文献   

Modelling spatio-temporal soil moisture dynamics in mountain tundra     

Vilna Tyystjrvi  Julia Kemppinen  Miska Luoto  Tuula Aalto  Tiina Markkanen  Samuli Launiainen  Antti-Jussi Kieloaho  Juha Aalto 《水文研究》2022,36(1):e14450

Soil moisture has a fundamental influence on the processes and functions of tundra ecosystems. Yet, the local dynamics of soil moisture are often ignored, due to the lack of fine resolution, spatially extensive data. In this study, we modelled soil moisture with two mechanistic models, SpaFHy (a catchment-scale hydrological model) and JSBACH (a global land surface model), and examined the results in comparison with extensive growing-season field measurements over a mountain tundra area in northwestern Finland. Our results show that soil moisture varies considerably in the study area and this variation creates a mosaic of moisture conditions, ranging from dry ridges (growing season average 12 VWC%, Volumetric Water Content) to water-logged mires (65 VWC%). The models, particularly SpaFHy, simulated temporal soil moisture dynamics reasonably well in parts of the landscape, but both underestimated the range of variation spatially and temporally. Soil properties and topography were important drivers of spatial variation in soil moisture dynamics. By testing the applicability of two mechanistic models to predict fine-scale spatial and temporal variability in soil moisture, this study paves the way towards understanding the functioning of tundra ecosystems under climate change.  相似文献   

Origin of post‐Minoan caves and volcaniclastic cave fill,Thera (Santorini), Greece     

Joan M. Ramage  George H. Shaw  Jeff A. Hoffman  Sarah A. Johnston 《Geoarchaeology》2003,18(5):523-539

The Aegean island of Thera (Santorini) was covered by tephra from its cataclysmic Late Bronze Age (ca. 3600 yr B.P.) eruption. Vertical exposures of the eruptive sequence show secondary, nonvolcanic, circular (in cross section) features composed of stratified sediment. Many are inaccessible from the floors of modern quarries and appear to be caves filled with younger sediment, but show no connection to the land surface. A filled cave was found in the wall of a modern gully outside the modern quarries, and a filled cave was found in a terrace scarp, well above the modern gully. Natural (and probably rapid) incision by gullies into the thick tephra deposit left many locations with lateral access to tephra. Inhabitants from post‐Minoan to recent times excavated tephra for materials and buildings, and caves were subsequently filled by sporadic (possibly seasonal) flood events that deposited sediment. These gullies may have provided access for modern tephra removal that isolated the filled caves high on the modern quarry walls. © 2003 Wiley Periodicals, Inc.  相似文献