Correction to: Beat-the-wave evacuation mapping for tsunami hazards in Seaside,Oregon, USA     

Priest  George R.  Gabel  Laura L.  Wood  Nathan J.  Madin  Ian P.  Watzig  Rudie J. 《Natural Hazards》2018,92(3):1509-1522

Natural Hazards - Due to a procedural error in construction of Figs.&;nbsp;8 and 9, listed minimum speeds to beat the tsunami wave in areas of Seaside seaward of Neawanna Creek are too high. The...  相似文献   

数字高程模型分辨率对流域地形特征参数的影响   总被引：2，自引：0，他引：2       下载免费PDF全文

林声盼  荆长伟  MOORE Nathan  吴嘉平 《水科学进展》2012,23(4):457-463

地形特征(如高程和坡度)和水文特征(如河流长度和河流坡度)是分布式流域水文水质模型的基础输入参数,用于量化描述模型模拟流域的自然特征。这些特征参数的准确性直接影响水文水质过程模拟的准确性。应用数字高程模型(Digital Elevation Model,DEM)在4个不同地形的子流域研究了10种不同分辨率DEM对平均高程、流域面积、坡度、河流坡度、最长河长等参数的影响。结果表明,随着DEM分辨率降低,流域地形变缓,流域平均坡度逐渐减小;随着DEM网格分辨率的变化,子流域划分范围和河道位置也都可能发生变化,且该变化在地形起伏较小的丘陵平原地区较明显,子流域集水面积和河长进一步随之改变;河流坡度随DEM分辨率降低则呈无规则变化。从地形和水文参数两方面揭示了DEM 分辨率在分布式流域模型中的不确定性影响。  相似文献   

Active Region Formation through the Negative Effective Magnetic Pressure Instability     

Koen Kemel  Axel Brandenburg  Nathan Kleeorin  Dhrubaditya Mitra  Igor Rogachevskii 《Solar physics》2013,287(1-2):293-313

The negative effective magnetic-pressure instability operates on scales encompassing many turbulent eddies, which correspond to convection cells in the Sun. This instability is discussed here in connection with the formation of active regions near the surface layers of the Sun. This instability is related to the negative contribution of turbulence to the mean magnetic pressure that causes the formation of large-scale magnetic structures. For an isothermal layer, direct numerical simulations and mean-field simulations of this phenomenon are shown to agree in many details, for example the onset of the instability occurs at the same depth. This depth increases with increasing field strength, such that the growth rate of this instability is independent of the field strength, provided the magnetic structures are fully contained within the domain. A linear stability analysis is shown to support this finding. The instability also leads to a redistribution of turbulent intensity and gas pressure that could provide direct observational signatures.  相似文献   

Iron content of the otoliths of tarakihi (Teleostei: Cheilodactylidae)     

R. W. Gauldie  Adrienne Nathan 《新西兰海洋与淡水研究杂志》2013,47(2):179-191

The otoliths (sagittae) of 1076 tarakihi Cheilodactylus macropterus collected from around the whole of New Zealand during 1968–69 were examined for heavy metal content by atomic absorption spectrometry. Copper, cadmium, nickel, manganese, and zinc did not occur in significant quantities, but iron was present in amounts ranging from 0.5 μg to 7.0 μg per otolith. The iron appears to be largely contained in the nucleus of the otolith. Variations in iron content per otolith indicate three regions where iron content is similar: a northern region (mean 3.39 μg; σ² = 1.35; n = 260); a central region (mean 1.92 μg; σ² = 1.32; n = 741); and a southern region (mean 0.96 μg; σ² = 0.45; n = 75). The significance of this regional variation, in otolith iron to the biology of the fish is not known, but may be linked by either heredity or environment to subpopulations of the fish.  相似文献   

Distribution,abundance and growth of New Zealand sea lion Phocarctos hookeri pups on Campbell Island     

Simon Childerhouse  Nadine Gibbs  Gus McAlister  Shaun McConkey  Helen McConnell  Nathan McNally 《新西兰海洋与淡水研究杂志》2013,47(4):889-898

Nine weeks field work was completed during two trips in January/February and March/ April 2003 to investigate the distribution and abundance of New Zealand sea lion Phocarctos hookeri pups at Campbell Island. A total of 161 pups were tagged and a further 138 dead pups were found. A closed mark‐recapture model was used to estimate the total number of live pups (e.g., tagged plus untagged pups) at Campbell Island in April as 247 (SE = 28, 95% CI 198–308). Pup production at Campbell Island is estimated at 385, which comprises 13% of the total pup production for the species in the 2003 season. This is the first robust estimate of pup production for New Zealand sea lions at Campbell Island. The figure of 385 pups is considerably higher than any of the previous estimates reported from Campbell Island. The high level of pup mortality (36%) at Campbell Island for approximately the first 2 months after birth is higher than the 17% reported for the Auckland Islands for approximately the same period in 2003, but is similar to unusually high levels of mortality (20–30%) reported at the Auckland Islands in recent years. It was not possible to determine the cause of death of the 138 dead pups owing to scavenging and decomposition. Pups were found over the whole Island, with the exception of its northern end. Male pups were significantly heavier and faster growing than female pups over the same period.  相似文献   

The ∼1100 Ma Sturgeon Falls paleosol revisited: Implications for Mesoproterozoic weathering environments and atmospheric CO₂ levels     

Ria L. Mitchell  Nathan D. Sheldon 《Precambrian Research》2010

During the active rifting stage of the ∼1100 Ma Midcontinental Rift in North America, alluvial sediments were deposited intermittently between basalt flows on the north and south shores of present day Lake Superior. At times of depositional quiescence, paleosols developed in both areas on the alluvial sediments and on the antecedent basalt. New results from the Sturgeon Falls paleosol in Michigan characterizing the weathering processes at the time of its formation indicate moderate maturity, high degrees of hydrolysis and leaching, and a low degree of salinization. Geochemical provenance indices indicate a homogeneous source for the paleosols, and in contrast to earlier work, there is little evidence for K metasomatism. As a result, atmospheric CO₂ levels of 4–6× pre-industrial atmospheric levels were calculated using a mass-balance model. This result is consistent with previous calculations from nearly contemporaneous paleosols from the other side of the Keweenawan Rift and from the ∼100 Ma younger Sheigra paleosol in Scotland. The calculated CO₂ values are also consistent with the calculated weathering environment proxies that indicate weak to moderate weathering at this time frame and suggest that the higher greenhouse gas loads indicated by Paleoproterozoic paleosols had dissipated by the mid-late Mesoproterozoic.  相似文献   

Phytoplankton Community Indicators of Short- and Long-term Ecological Change in the Anthropogenically and Climatically Impacted Neuse River Estuary, North Carolina, USA     

Hans W. Paerl  Karen L. Rossignol  S. Nathan Hall  Benjamin L. Peierls  Michael S. Wetz 《Estuaries and Coasts》2010,33(2):485-497

Estuarine and coastal systems represent a challenge when it comes to determining the causes of ecological change because human and natural perturbations often interact. Phytoplankton biomass (chlorophyll a) and group-specific photopigment indicators were examined from 1994 to 2007 to assess community responses to nutrient and climatic perturbations in the Neuse River Estuary, NC. This system experienced nutrient enrichment and hydrologic variability, including droughts, and an increase in hurricanes. Freshwater input strongly interacted with supplies of the limiting nutrient nitrogen (N) and temperature to determine the location, magnitude, and composition of phytoplankton biomass. Multi-annual, seasonal, and episodic hydrologic perturbations, including changes in the frequency and intensity of tropical storms, hurricanes and droughts, caused significant shifts in phytoplankton community structure. Climatic oscillations can at times overwhelm anthropogenic nutrient inputs in terms of controlling algal bloom thresholds, duration, and spatial extent. Eutrophication models should incorporate climatically driven changes to better predict phytoplankton community responses to nutrient inputs and other anthropogenic perturbations.  相似文献   

Effect of Ni2+, Zn2+, and Co2+ on green rust transformation to magnetite     

Farr  Orion  Elzinga  Evert J.  Yee  Nathan 《Geochemical transactions》2022,23(1):1-25

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