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131.
132.
Drinkwater Kenneth F.; Loeng Harald; Megrey Bernard A.; Bailey Nick; Cook Robin M. 《ICES Journal of Marine Science》2005,62(7):1203-1204
An ICES Symposium on The Influence of Climate Change on NorthAtlantic Fish Stocks was held in Bergen, Norway, from 11 to14 May 2004. The Symposium, sponsored by the ICES/GLOBEC WorkingGroup on Cod and Climate Change (WGCCC) as part of their synthesisactivities, was convened to address the issue of climate variabilityand its impact on cod and other fish stocks in the North Atlantic.It followed 11 years after the first WGCCC-sponsored ICES Symposiumon Cod and Climate (ICES, 1994) in Reykjavík, Iceland,which was convened to gather together the then current knowledgeof the influence of climate variability on cod. The 2004 Symposiumwas timely 相似文献
133.
Shane Greene Nick Battye Ian Clark Tom Kotzer Dennis Bottomley 《Geochimica et cosmochimica acta》2008,72(16):4008-4019
Dissolved noble gas concentrations were measured in high salinity (270 g/L) Ca(Na)-Cl groundwaters from the Con Mine, Yellowknife, Canada in an effort to discriminate between two possible origins, as either a brine generated by evaporative enrichment in a Paleozoic inland sea, or marine water concentrated by freezing during glacial times. Major ion and isotope geochemistry indicate that brines from the deepest level remain relatively undisturbed by mixing with modern water introduced by mining. Mixing calculations are used to quantify fractions of brine, glacial meltwater and modern water. From this, noble gas concentrations were corrected for excess air with Ne and normalized to 100% brine solution. Over-pressuring of helium and argon in the brine provide age constraints based on the accumulation of geogenic 4He and 40Ar. Radiogenic age calculations together with the local geological history suggest brine emplacement during early Palaeozoic time, likely during the Devonian when evaporitic inland seas existed in this region. The concentrations of the atmospherically derived noble gases in the brine fraction (Kr = 1.4E-8, Xe = 8.5E-10 ccSTP/ccH2O) are close to atmospheric equilibrium for brine at 25 °C (Kr = 7.3E-9, Xe = 8.0E-10 ccSTP/ccH2O), but are far lower than would be expected for closed-system concentration of seawater by freezing (Kr = 2.8E-6, Xe = 4.2E-7 ccSTP/ccH2O). Thus, despite the complicated mixing history of the brine, the atmospheric and geogenic noble gases provide strong evidence for an origin as air-equilibrated brine from evaporated Paleozoic seawater, which infiltrated via density displacement through existing fractures and faults into the Canadian Shield. 相似文献
134.
Nick Bingham 《Geoforum》2008,39(1):111-122
This paper stages an encounter between one strand of the controversy around genetically modified food crops and some conceptual resources from the field of science and technology studies, with the aim of illuminating the relationship between science and politics. Contrary to some suggestions, it is argued that the spatial, temporal and material imagination encapsulated in the figure of Progress remains central to their contemporary articulation. Best described as an ‘anti-political’ strategy, Progress does not leave room for anything else but one story of the world. Through following the attempts of both scientists in the field and protestors on the streets to make public some of the trajectories which this story leaves out, what emerges is the possibility of an alternative to Progress that is not based simply on its rejection. Instead, such efforts offer resources for inventing another way of collectively going forward which chime with some more theoretical attempts to elaborate how things might be productively ‘slowed down’. An example of how government was forced to construct a way of dealing with things that is more adequate and appropriate to life in a full world is compared with Bruno Latour’s model of due process for nonhumans, before some conclusions are drawn about whether we should be depressed or hopeful about our ability to move on in the lights of such attempts. 相似文献
135.
Philip E.BETT Adam A.SCAIFE Chaofan LI Chris HEWITT Nicola GOLDING Peiqun ZHANG Nick DUNSTONE Doug M.SMITH Hazel E.THORNTON Riyu LU Hong-Li REN 《大气科学进展》2018,35(8):918-926
The Yangtze River has been subject to heavy flooding throughout history,and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods.Dams along the river help to manage flood waters,and are important sources of electricity for the region.Being able to forecast high-impact events at long lead times therefore has enormous potential benefit.Recent improvements in seasonal forecasting mean that dynamical climate models can start to be used directly for operational services.The teleconnection from El Ni ?no to Yangtze River basin rainfall meant that the strong El Ni ?no in winter 2015/16 provided a valuable opportunity to test the application of a dynamical forecast system.This paper therefore presents a case study of a real-time seasonal forecast for the Yangtze River basin,building on previous work demonstrating the retrospective skill of such a forecast.A simple forecasting methodology is presented,in which the forecast probabilities are derived from the historical relationship between hindcast and observations.Its performance for2016 is discussed.The heavy rainfall in the May–June–July period was correctly forecast well in advance.August saw anomalously low rainfall,and the forecasts for the June–July–August period correctly showed closer to average levels.The forecasts contributed to the confidence of decision-makers across the Yangtze River basin.Trials of climate services such as this help to promote appropriate use of seasonal forecasts,and highlight areas for future improvements. 相似文献
136.
This report analyses a decade of geography scholarship student entry and achievement data (n = 10,205) to reveal patterns and trends of high‐achieving school students. The study is an exploratory analysis, the aim of which is to describe where the greatest scholarship success has occurred, as well as attendant demographic characteristics of New Zealand's most capable geography students and their schools. Emerging from the regions is a localised story of students from an extremely narrow number of schools achieving disproportionate scholarship success. This raises questions in the wider geography teaching community about the possibility of a broader constituency achieving scholarship awards. 相似文献
137.
Timing of the first drainage of the Baltic Ice Lake synchronous with the onset of Greenland Stadial 1
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Francesco Muschitiello James M. Lea Sarah L. Greenwood Faezeh M. Nick Lars Brunnberg Alison MacLeod Barbara Wohlfarth 《Boreas: An International Journal of Quaternary Research》2016,45(2):322-334
Glacial varves can give significant insights into recession and melting rates of decaying ice sheets. Moreover, varve chronologies can provide an independent means of comparison to other annually resolved climatic archives, which ultimately help to assess the timing and response of an ice sheet to changes across rapid climate transitions. Here we report a composite 1257‐year‐long varve chronology from southeastern Sweden spanning the regional late Allerød–late Younger Dryas pollen zone. The chronology was correlated to the Greenland Ice‐Core Chronology 2005 using the time‐synchronous Vedde Ash volcanic marker, which can be found in both successions. For the first time, this enables secure placement of the Lateglacial Swedish varve chronology in absolute time. Geochemical analysis from new varve successions indicate a marked change in sedimentation regime accompanied by an interruption of ice‐rafted debris deposition synchronous with the onset of Greenland Stadial 1 (GS‐1; 12 846 years before AD 1950). With the support of a simple ice‐flow/calving model, we suggest that slowdown of sediment transfer can be explained by ice‐sheet margin stabilization/advance in response to a significant drop of the Baltic Ice Lake level. A reassessment of chronological evidence from central‐western and southern Sweden further supports the hypothesis of synchronicity between the first (penultimate) catastrophic drainage of the Baltic Ice Lake and the start of GS‐1 in Greenland ice‐cores. Our results may therefore provide the first chronologically robust evidence linking continental meltwater forcing to rapid atmosphere–ocean circulation changes in the North Atlantic. 相似文献
138.
139.
Daniel N. Baker Dusan Odstrcil Brian J. Anderson C. Nick Arge Mehdi Benna George Gloeckler Haje Korth Leslie R. Mayer Jim M. Raines David Schriver James A. Slavin Sean C. Solomon Pavel M. Trávní?ek Thomas H. Zurbuchen 《Planetary and Space Science》2011,59(15):2066-2074
The second and third flybys of Mercury by the MESSENGER spacecraft occurred, respectively, on 6 October 2008 and on 29 September 2009. In order to provide contextual information about the solar wind properties and the interplanetary magnetic field (IMF) near the planet at those times, we have used an empirical modeling technique combined with a numerical physics-based solar wind model. The Wang–Sheeley–Arge (WSA) method uses solar photospheric magnetic field observations (from Earth-based instruments) in order to estimate the inner heliospheric radial flow speed and radial magnetic field out to 21.5 solar radii from the Sun. This information is then used as input to the global numerical magnetohydrodynamic model, ENLIL, which calculates solar wind velocity, density, temperature, and magnetic field strength and polarity throughout the inner heliosphere. WSA-ENLIL calculations are presented for the several-week period encompassing the second and third flybys. This information, in conjunction with available MESSENGER data, aid in understanding the Mercury flyby observations and provide a basis for global magnetospheric modeling. We find that during both flybys, the solar wind conditions were very quiescent and would have provided only modest dynamic driving forces for Mercury's magnetospheric system. 相似文献
140.
Penelope J. WOZNIAKIEWICZ Hope A. ISHII Anton T. KEARSLEY Mark J. BURCHELL Philip A. BLAND John P. BRADLEY Zurong DAI Nick TESLICH Gareth S. COLLINS Mike J. COLE Sara S. RUSSELL 《Meteoritics & planetary science》2011,46(7):1007-1024
Abstract– Samples returned from comet 81P/Wild 2 by the Stardust mission provided an unequaled opportunity to compare previously available extraterrestrial samples against those from a known comet. Iron sulfides are a major constituent of cometary grains commonly identified within cometary interplanetary dust particles (IDPs) and Wild 2 samples. Chemical analyses indicate Wild 2 sulfides are fundamentally different from those in IDPs. However, as Wild 2 dust was collected via impact into capture media at approximately 6.1 km s?1, it is unclear whether this is due to variation in preaccretional/parent body processes experienced by these materials or due to heating and alteration during collection. We investigated alteration in pyrrhotite and pentlandite impacted into Stardust flight spare Al foils under encounter conditions by comparing scanning and transmission electron microscope (SEM, TEM) analyses of preimpact and postimpact samples and calculating estimates of various impact parameters. SEM is the primary method of analysis during initial in situ examination of Stardust foils, and therefore, we also sought to evaluate the data obtained by SEM using insights provided by TEM. We find iron sulfides experience heating, melting, separation, and loss of S, and mixing with molten Al. These results are consistent with estimated peak pressures and temperatures experienced (approximately 85 GPa, approximately 2600 K) and relative melting temperatures. Unambiguous identification of preserved iron sulfides may be possible by TEM through the location of Al‐free regions. In most cases, the Ni:Fe ratio is preserved in both SEM and TEM analyses and may therefore also be used to predict original chemistry and estimate mineralogy. 相似文献