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1.
Following the 14th International Workshop on Wave Hindcasting and Forecasting and 5th Coastal Hazards Symposium in November 2014 in Key West, Florida, a topical collection has appeared in recent issues of Ocean Dynamics. Here, we give a brief overview of the 16 papers published in this topical collection as well as an overview of the widening scope of the conference in recent years. A general trend in the field has been towards closer integration between the wave and ocean modelling communities. This is also seen in this topical collection, with several papers exploring the interaction between surface waves and mixed layer dynamics and sea ice. 相似文献
2.
AbstractThe ability of hydrological models to deal with changing conditions should not be taken for granted: it is an unfortunate but well-known problem of hydrology that the model structure and/or parameters optimized for certain conditions may not be transferable in time. Consequently, it is essential that, for application under changing conditions (e.g. in climate change impact studies), models be thoroughly assessed for their extrapolation capacity using adequate protocols. This editorial provides an overview of the Special Issue of Hydrological Sciences Journal compiled after a workshop on this theme held during the General Assembly of the International Association of Hydrological Sciences (IAHS) in Gothenburg (Sweden) in 2013. The Workshop participants had been invited to apply a calibration and evaluation protocol to their own models on a given set of changing basins. The results show that this protocol is an appropriate and instructive way of assessing the suitability of hydrological models to be applied under changing conditions. This special issue also includes papers following alternative testing methodologies, as well as an opinion paper on the definition of non-stationarity. 相似文献
3.
“空间技术揭示的古吉拉特地震的地球系统过程”国际研讨会于2003年1月27－29日在印度坎普尔举行。来自印度、美国、中国、德国和俄罗斯约80位专家参加了该研讨会。会计收到约70篇研究报告。文章介绍了会议概况、学术报告和专题辩论的情况。 相似文献
4.
2003年9月24～26日“第五届中哈现代地球动力学和中亚地震危险国际学术研讨会”在哈萨克斯坦阿拉木图举行。来自7个国家140名代表参加了会议。文章介绍了会议概况、学术交流、取得的成果，以及几点认识。 相似文献
5.
A topical collection on “Advances in Search and Rescue at Sea” has appeared in recent issues of Ocean Dynamics following the latest in a series of workshops on “Technologies for Search and Rescue and other Emergency Marine Operations” (2004, 2006, 2008, and 2011), hosted by IFREMER in Brest, France. Here, we give a brief overview of the history of search and rescue at sea before we summarize the main results of the papers that have appeared in the topical collection. 相似文献
6.
Fifteen papers are included in Volume 2 of a PAGEOPH topical issue Tsunamis in the World Ocean: Past, Present, and Future. These papers are briefly introduced. They are grouped into three categories: reports and studies of recent tsunamis, studies
on tsunami statistics and application to tsunami warning, and modeling studies of tsunami runup and inundation. Most of the
papers were presented at the 24th International Tsunami Symposium held 14–16 July 2009 in Novosibirsk, Russia, and reflect
the current state of tsunami science. 相似文献
7.
The International Workshop on Strong-motion Earthquake Instrument Arrays was held during 2-5 May 1978 in Honolulu, Hawaii. The goal of the workshop was to develop a workable plan for the possible future deployment of dense strong-motion arrays with primary emphasis on ground motion studies. Topics considered by the workshop included: favourable array locations, the design of arrays for source mechanism and wave propagation studies, the design of arrays for local effects studies, array construction and operation, and implementation. This paper gives a summary of the recommendations and conclusions of the workshop. 相似文献
8.
Abstract This is an updated and extended presentation of the results of the IAHS Workshop on Quality Assurance in Hydrologic Measurement, held during the XXI General Assembly of the International Union of Geodesy and Geophysics (IUGG), Boulder, Colorado, USA, in July 1995. The main focus at Boulder was on experience with hydrological applications of the international standard ISO 9002 and developments in rating curve theory. A case study of a quality assurance system is presented. Progress in hydrometric quality assurance since the workshop and areas for future development are discussed. 相似文献
9.
Wave generation, propagation, and transformation from deep ocean over complex bathymetric terrains to coastal waters around Potter Cove (King George Island, South Shetland Islands, Antarctica) have been simulated for an austral summer month using the Simulating Waves Nearshore (SWAN) wave model. This study aims to examine and understand the wave patterns, energy fluxes, and dissipations in Potter Cove. Bed shear stress due to waves is also calculated to provide a general insight on the bed sediment erosion characteristics in Potter Cove.A nesting approach has been implemented from an oceanic scale to a high-resolution coastal scale around Potter Cove. The results of the simulations were compared with buoy observations obtained from the National Data Buoy Center, the WAVEWATCH III model results, and GlobWave altimeter data. The quality of the modelling results has been assessed using two statistical parameters, namely the Willmott’s index of agreement D and the bias index. Under various wave conditions, the significant wave heights at the inner cove were found to be about 40–50 % smaller than the ones near the mouth of Potter Cove. The wave power in Potter Cove is generally low. The spatial distributions of the wave-induced bed shear stress and active energy dissipation were found to be following the pattern of the bathymetry, and waves were identified as a potential major driving force for bed sediment erosion in Potter Cove, especially in shallow water regions. This study also gives some results on global ocean applications of SWAN. 相似文献
10.
The cross-sectional stability of double inlet systems is investigated using an exploratory model that combines Escoffier’s stability concept for the evolution of the inlet’s cross-sectional area with a two-dimensional, depth-averaged (2DH) hydrodynamic model for tidal flow. The model geometry consists of four rectangular compartments, each with a uniform depth, associated with the ocean, tidal inlets and basin. The water motion, forced by an incoming Kelvin wave at the ocean’s open boundary and satisfying the linear shallow water equations on the f -plane with linearised bottom friction, is in each compartment written as a superposition of eigenmodes, i.e. Kelvin and Poincaré waves. A collocation method is employed to satisfy boundary and matching conditions. The analysis of resulting equilibrium configurations is done using flow diagrams. Model results show that internally generated spatial variations in the water motion are essential for the existence of stable equilibria with two inlets open. In the hydrodynamic model used in the paper, both radiation damping into the ocean and basin depth effects result in these necessary spatial variations. Coriolis effects trigger an asymmetry in the stable equilibrium cross-sectional areas of the inlets. Furthermore, square basin geometries generally correspond to significantly larger equilibrium values of the inlet cross-sections. These model outcomes result from a competition between a destabilising (caused by inlet bottom friction) and a stabilising mechanism (caused by spatially varying local pressure gradients over the inlets). 相似文献
11.
Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth’s temperature and consequently have led to changes in wind and wave regimes. The main effects of climate change on oceans are warming of the ocean water, melting of ice, acidification of ocean water, and change in the ocean currents. The main effects of climate change on coastal regions are change in the coast hydrodynamics, sea level rise, change in wave height, coastal erosion, coastal structure damage, food shortage, and storms. Due to the importance of waves in the coastal zone and its effect on erosion and sedimentation, it is necessary to study wave changes. In this study, the effect of climate change on wave specifications was evaluated in the southern coast of the Caspian Sea in Noshahr Port. To simulate wave parameters, the third generation spectral Simulating WAves Nearshore (SWAN) model was used. Wave modeling was carried out using the SWAN numerical model for two 30-yearly periods, including the control period (1984 to 2014) and the future period (2051 to 2080). For wave modeling in the control period, the European Center for Average Weather Forecast wind field was used, and for the future period, a downscaled wind field from Coordinated Regional Downscaling Experiment projection, which was sponsored by World Climate Research Programme, based on the most recent emission scenarios RCP2.6, RCP4.5, and RCP8.5, was used. The model results were calibrated and verified with buoy-recorded data. The effect of the climate change on the wave parameters was evaluated by studying the differences between the patterns in three scenarios and the control period. Results showed that the 30-year maximum significant wave height will increase because of climate change, and the wave direction will not change. In addition, the intensity of storms will increase in the future. 相似文献
12.
Knowledge of upper ocean currents is needed for trajectory forecasts and is essential for search and rescue operations and oil spill mitigation. This paper addresses effects of surface waves on ocean currents and drifter trajectories using in situ observations. The data set includes colocated measurements of directional wave spectra from a wave rider buoy, ocean currents measured by acoustic Doppler current profilers (ADCPs), as well as data from two types of tracking buoys that sample the currents at two different depths. The ADCP measures the Eulerian current at one point, as modelled by an ocean general circulation model, while the tracking buoys are advected by the Lagrangian current that includes the wave-induced Stokes drift. Based on our observations, we assess the importance of two different wave effects: (a) forcing of the ocean current by wave-induced surface fluxes and the Coriolis–Stokes force, and (b) advection of surface drifters by wave motion, that is the Stokes drift. Recent theoretical developments provide a framework for including these wave effects in ocean model systems. The order of magnitude of the Stokes drift is the same as the Eulerian current judging from the available data. The wave-induced momentum and turbulent kinetic energy fluxes are estimated and shown to be significant. Similarly, the wave-induced Coriolis–Stokes force is significant over time scales related to the inertial period. Surface drifter trajectories were analysed and could be reproduced using the observations of currents, waves and wind. Waves were found to have a significant contribution to the trajectories, and we conclude that adding wave effects in ocean model systems is likely to increase predictability of surface drifter trajectories. The relative importance of the Stokes drift was twice as large as the direct wind drag for the used surface drifter. 相似文献
13.
AbstractA Kelvin wave in a semi-infinite ocean with a narrow (compared with the wavelength) continental shelf is diffracted by a narrow gap that feeds any of a second semi-infinite ocean, a semi-infinite channel, a closed channel of finite length, a small bay, or a channel terminated by a bay. An equivalent electrical circuit is constructed, in which the incident-wave displacement in the gap appears as the input voltage and the flow into the gap appears as the input current. Approximations to the elements of this circuit are constructed from a quadratic functional that is derived from the integral equation implied by the boundary-value problem. The phase shift in the diffracted Kelvin wave is calculated, and numerical results are given for representative configurations. The general results are applicable to other tidal waves in the semi-infinite ocean, e.g., a Poincaré wave. A model of San Francisco Bay, opening into the ocean through a short, narrow channel (the Golden Gate) and fed by rivers through a long channel (Carquinez Straits), is constructed. It yields a resonant period of 4.6h and a time delay of 3.6 sec for a semi-diurnal (12.4h) Kelvin wave. 相似文献
14.
为了解决海底起伏变化对地震波场的影响问题,本文提出将（x-z）域中的曲网格映射成（ξ,η）域中的矩形网格,推导出（ξ,η）域中的二维标量声波方程,根据推导出来的波动方程采用逆时有限差分法将海面上采集到的地震波场在（ξ,η）域中向下延拓至海底面,延拓时采用海水的速度,然后采用顺时有限差分法将延拓后的地震波场再反延拓到海面上,延拓时采用海底面以下地层的速度,从而消除了海底起伏带来的负面影响。模型及实际地震资料的计算分析表明该方法不但能够校正由于海底起伏所引起的海底面下地层反射波场的不连续性还能够校正由于海底起伏所引起的地震波的动力学特征的变化。对延拓前后的地震波场进行速度反演,延拓后反演的地层速度比延拓前反演的地层速度的精度提高很多,延拓前后地震波场的叠加剖面对比表明该延拓方法能够明显提高地震波场的成像质量。 相似文献
16.
The papers in this special issue reflect several of the major themes and topics from the 7 th International Workshop on Gravel‐Bed Rivers. The papers focus primarily on aspects of bed material transport in gravel‐bed rivers and larger scale morpho‐dynamics. Research in gravel‐bed rivers is increasingly integrating processes over a wide range of temporal and spatial scales by combining field observation, lab experimentation, numerical modeling and theory testing in a range of river types, aided by new technological developments in particle tracking, computational modeling and high resolution spatial data. This is leading to greater understanding of the processes leading to distinctive morpho‐dynamics of river types and a more reliable basis for river management. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
17.
Eighteen papers are included in Volume 1 of a PAGEOPH topical issue Tsunamis in the World Ocean: Past, Present, and Future. These papers are briefly introduced. They are grouped into three categories: case studies of earthquake-generated tsunamis; tsunami forecast and hazard assessments; and theoretical and computational modeling of tsunami generation, propagation, and coastal behavior. Most of the papers were presented at the 24th International Tsunami Symposium held 14?C16 July 2009 in Novosibirsk, Russia, and reflect the current state of tsunami science. 相似文献
18.
‘Aggregation’ refers to spatial averaging of some heterogeneous surface variable to obtain an effective value representative of an area. The effect of surface heterogeneity on interactions between land and atmosphere is relevant to near-surface hydrology, ecology, and climate, and is the common theme of the papers in this issue. Even though the full effect of heterogeneity must be neglected owing to limited spatial resolution of large-scale models, it is important to understand when and how the presence of heterogeneity requires recognition in any aggregate representation. In March 1994, a workshop, which has come to be known as the ‘Tucson Aggregation Workshop’, was convened to assess the state of the art in aggregation research, and the papers in this issue are the product of that workshop. The principal findings of the workshop can be summarized as follows: - 1. 1. substantial progress has been made in producing aggregated representations of flat terrain. Simple aggregation rules applied to surface properties have given rise, in some studies, to simulated surface energy fluxes that are within 10% of fluxes produced from models with full representation of heterogeneity.
- 2. 2. Aggregation rules are relatively straightforward in the case of patch-scale heterogeneity (variability on the order of hundreds to thousands of meters) of vegetative characteristics which control surface exchanges, although aggregation of soil hydraulic properties and possibly of soil moisture remains problematic. In addition, some of the effects of meso-scale heterogeneity (variability on the order or 10–100 km) in surface cover will need to be addressed through more complicated types of parameterization.
- 3. 3. There is convincing evidence that the regional energy balance (over, say, 105 km2) is insensitive to gentle topography, provided that surface vegetation and water availability are uniform, but in mountainous terrain the influence of topography on near-surface meteorology must be considered.
- 4. 4. It appears that the value of simple combinations of remotely sensed radiances representing areal-average measurements are influenced only slightly by unresolved variability, although the averaging of some derived variables based on these radiances offers a greater challenge, especially with sparse canopies.
相似文献
19.
Following the recent reports by Y uan et al. (2005) of recordings of the 2004 Sumatra tsunami on the horizontal components of coastal seismometers in the Indian Ocean
basin, we build a much enhanced dataset extending into the Atlantic and Pacific Oceans, as far away as Bermuda and Hawaii,
and also expanded to five additional events in the years 1995–2006. In order to interpret these records quantitatively, we
propose that the instruments are responding to the combination of horizontal displacement, tilt and perturbation in gravity
described by G ilbert (1980), and induced by the passage of the progressive tsunami wave over the ocean basin. In this crude approximation, we
simply ignore the island or continent structure, and assume that the seismometer functions de facto as an ocean-bottom instrument. The records can then be interpreted in the framework of tsunami normal mode theory,and lead
to acceptable estimates of the seismic moment of the parent earthquakes. We further demonstrate the feasibility of deconvolving
the response of the ocean floor in order to reconstruct the time series of the tsunami wave height at the surface of the ocean,
suggesting that island or coastal continental seismometers could complement the function of tsunameters. 相似文献
20.
与地震预报有关的电磁现象国际学术讨论会已于１９９３年９月６－８日在东京召开。这次学术讨论会的宗旨是，为世界各国学者提供一个公开讲坛以讨论与地震有关的电磁现象，并通过交叉学科与多科学相关领域相结合的方式探讨地震预报等问题。本文较详细地介绍了各国学者在这一领域中的最新成果。 相似文献
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