Reaktionen benthischer Tiefsee-Lebensgemeinschaften auf mechanische Störungen der Sedimente     

Bluhm  Hartmut  Borowski  Christian  Ahnert  Ahmed  Vopel  Kay  Schriever  Gerd  Thiel  Hjalmar 《Ocean Dynamics》1999,51(10):149-152

Ocean Dynamics - Das Ökosystem der Tiefsee wird zunehmend durch industrielle Eingriffe beeinflusst. Über die Auswirkungen dieser Aktivitäten auf das Benthos wurden bisher nur...  相似文献   

Particle tracking experiments on a model of the Okhotsk Sea: Toward oil spill simulation   总被引：2，自引：1，他引：1  

Kay I. Ohshima  Daisuke Simizu 《Journal of Oceanography》2008,64(1):103-114

Particle tracking experiments were conducted for the Sea of Okhotsk using a three-dimensional ocean circulation model, as a step toward the simulation of oil spills. The model’s reproducibility is first examined in detail. Comparison with surface drifter and moored ADCP data shows that the model successfully reproduces the velocity field over the shelves, particularly in the weak stratification period. This is because the current variability is simply determined by integration of the alongshore component of the wind stress over the coast from which arrested topographic waves propagate. Good agreement even in the ice-covered period implies that the neglect of sea ice in the model is not a problem for reproduction of the current over the shelves. Good agreement also supports the correction of ECMWF wind speed by a factor of 1.25. A series of particle tracking experiments was carried out to examine the case of particles released from the Sakhalin oil field at depths of 0 m and 15 m. Regardless of the deployment month and year, most particles at depth 15 m are transported southward along the Sakhalin coast, in accordance with the abrupt intensification of the East Sakhalin Current in October, finally arriving offshore of Hokkaido in November–January. Particles at the surface, which are affected by wind drift in addition to the ocean current, show larger yearly variability. In years when the offshoreward-wind dominates, the particles would be advected out of the mainstream of the current and would not be transported offshore of Hokkaido.  相似文献   

Volume transport of the Soya Warm Current revealed by bottom-mounted ADCP and ocean-radar measurement   总被引：2，自引：2，他引：0  

Yasushi Fukamachi  Iori Tanaka  Kay I. Ohshima  Naoto Ebuchi  Genta Mizuta  Hideo Yoshida  Shiro Takayanagi  Masaaki Wakatsuchi 《Journal of Oceanography》2008,64(3):385-392

The vertical structure of the Soya Warm Current (SWC) was observed by a bottom-mounted acoustic Doppler current profiler (ADCP) in the region of the SWC axis near the Soya Strait during a 1-year period from May 2004. The ADCP data revealed a marked seasonal variability in the vertical structure, with positive (negative) vertical shear in summer and fall (winter and spring). The volume transport of the SWC is estimated on the basis of both the vertical structure observed by the ADCP and horizontal structure observed by the ocean radars near the strait. The transport estimates have a minimum in winter and a maximum in fall, with the yearly-averaged values in the range of 0.94–1.04 Sv (1 Sv = 10⁶ m³ s⁻¹). These lie within a reasonable range in comparison to those through other straits in the Japan Sea.  相似文献   

The impact of climate change on U. K. river flows: A preliminary comparison of two generations of probabilistic climate projections     

Alison Lindsey Kay  Glenn Watts  Steven C. Wells  Stuart Allen 《水文研究》2020,34(4):1081-1088

The impacts of climate change on future river flows are a growing concern. Typically, impacts are simulated by driving hydrological models with climate model ensemble data. The U.K. Climate Projections 2009 (UKCP09) provided probabilistic projections, enabling a risk-based approach to decision-making under climate change. Recently, an update was released—UKCP18—so there is a need for information on how impacts may differ. The probabilistic projections from UKCP18 and UKCP09 are here applied using the change factor method with catchment-based hydrological modelling for 10 catchments across England. Projections of changes in median, mean, high, and low flows are made for the 2050s, using the A1B emissions scenario from UKCP09 and UKCP18 as well as the RCP4.5 and RCP8.5 emissions scenarios from UCKP18. The results show that, in all catchments for all flow measures, the central estimate of change under UKCP18 is similar to that from UKCP09 (A1B emissions). However, the probabilistic uncertainty ranges from UKCP18 are, in all cases, greater than from UKCP09, despite UKCP18 having a smaller ensemble size than UKCP09. Although there are differences between the central estimates of change using UKCP18 RCP4.5, RCP8.5 and A1B emissions, there is considerable overlap in the uncertainty ranges. The results suggest that existing assessments of hydrological impacts remain relevant, though it will be necessary to evaluate sensitive decisions using the latest projections. The analysis will aid development of advice to users of current guidance based on UKCP09 and help make decisions about the prioritization of further hydrological impacts work using UKCP18, which should also apply other products from UKCP18 like the 12-km regional data.  相似文献   

Using response surfaces to estimate impacts of climate change on flood peaks: assessment of uncertainty          下载免费PDF全文

A. L. Kay  S. M. Crooks  N. S. Reynard 《水文研究》2014,28(20):5273-5287

The potential impacts of climate change are an increasing focus of research, and ever‐larger climate projection ensembles are available, making standard impact assessments more onerous. An alternative way of estimating impacts involves response surfaces, which present the change in a given indicator for a large number of plausible climatic changes defined on a regular sensitivity domain. Sets of climate change projections can then be overlaid on the response surface and impacts estimated from the nearest corresponding points of the sensitivity domain, providing a powerful method for fast impact estimation for multiple projections and locations. However, the effect of assumptions necessary for initial response surface development must be assessed. This paper assesses the uncertainty introduced by use of a sensitivity framework for estimating changes in 20‐year return period flood peaks in Britain. This sensitivity domain involves mean annual and seasonal precipitation changes, and a number of simplifications were necessary for consistency and to reduce dimensionality. The effect of these is investigated for nine catchments across Britain, representing nine typical response surfaces (response types), using three sets of climate projections. The results show that catchments can have different causes of uncertainty and some catchments have an overall higher level of uncertainty than others. These differences are compatible with the underlying climatological and hydrological differences between the response types, giving confidence in generalization of the results. This enables the development of uncertainty allowances by response type, to be used alongside the response surfaces to provide more robust impact estimates. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Weathering of the black limestone of historical monuments (Ljubljana,Slovenia): Oxygen and sulfur isotope composition of sulfate salts     

Sabina Kramar  Breda Mirtič  Kay Knöller  Nastja Rogan-Šmuc 《Applied Geochemistry》2011,26(9-10):1632-1638

The black limestone widely used in Slovenian monuments, particularly in the baroque architecture, is deteriorating extensively due to salt crystallization. Samples of soluble salts from two important historical monuments (in Ljubljana, Slovenia) were investigated in terms of their mineral and isotopic (S and O) compositions. Results revealed the presence of gypsum and soluble salts of the MgSO₄·nH₂O series, such as starkeyite (MgSO₄·4H₂O), pentahydrite (MgSO₄·5H₂O) and hexahydrite (MgSO₄·6H₂O). Whereas black crusts and subflorescences consisted of gypsum, efflorescences appeared to be an assemblage of gypsum and MgSO₄ hydrates. Sample δ¹⁸O_sulfate values varied from ?1.9‰ to +5.5‰ vs. V-SMOW and δ³⁴S_sulfate values from ?19.8‰ to +3.2‰ vs. V-CDT. The respective isotopic composition of analysed outdoor and indoor monument samples indicated different sources of contamination.  相似文献   

Cosmological simulations of the intracluster medium     

Scott T. Kay  Peter A. Thomas  Adrian Jenkins  Frazer R. Pearce 《Monthly notices of the Royal Astronomical Society》2004,355(4):1091-1104

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The effect of cooling and preheating on the X-ray properties of clusters of galaxies     

Orrarujee Muanwong  Peter A. Thomas  Scott T. Kay  Frazer R. Pearce 《Monthly notices of the Royal Astronomical Society》2002,336(2):527-540

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COUNCIL MEETING,SEATTLE April 26-27, 1974     

Samuel Kay  Bo Zhao  Daniel Sui 《The Professional geographer》2013,65(3):351-363

Since the U.S. Embassy in Beijing placed an air quality sensor on its roof and began publishing the results on Twitter in 2008, air quality has gained widespread attention on Chinese microblogs. When the Chinese government introduced new air quality standards in 2012, some hailed this as a victory for Chinese microbloggers, signifying the emergence of social media as a democratizing force leading to greater citizen power. Using a representative sample of microblog posts collected from October 2012 to June 2013 on the topic of air pollution, as well as contextual information from a variety of sources, we examine how the government, companies, nongovernmental organizations, and individuals approach the Chinese social media landscape. We find that although microblogs are capable of empowering citizens to advance an environmental cause, social media have also been increasingly employed by the government as a tool for social monitoring and control and by companies as a platform for profiting from air pollution.  相似文献   

Determination of groundwater discharge rates and water residence time of groundwater‐fed lakes by stable isotopes of water (18O, 2H) and radon (222Rn) mass balances          下载免费PDF全文

Eric Petermann  John J. Gibson  Kay Knöller  Thomas Pannier  Holger Weiß  Michael Schubert 《水文研究》2018,32(6):805-816

Lacustrine groundwater discharge (LGD) and the related water residence time are crucial parameters for quantifying lake matter budgets and assessing its vulnerability to contaminant input. Our approach utilizes the stable isotopes of water (δ¹⁸O, δ²H) and the radioisotope radon (²²²Rn) for determining long‐term average and short‐term snapshots in LGD. We conducted isotope balances for the 0.5‐km² Lake Ammelshainer See (Germany) based on measurements of lake isotope inventories and groundwater composition accompanied by good quality and comprehensive long‐term meteorological and isotopic data (precipitation) from nearby monitoring stations. The results from the steady‐state annual isotope balances that rely on only two sampling campaigns are consistent for both δ¹⁸O and δ²H and suggested an overall long‐term average LGD rate that was used to infer the water residence time of the lake. These findings were supported by the good agreement of the simulated LGD‐driven annual cycles of δ¹⁸O and δ²H lake inventories with the observed lake isotope inventories. However, radon mass balances revealed lower values that might be the result of seasonal LGD variability. For obtaining further insights into possible seasonal variability of groundwater–lake interaction, stable water isotope and radon mass balances could be conducted more frequently (e.g., monthly) in order to use the derived groundwater discharge rates as input for time‐variant isotope balances.  相似文献