Imprints of wave climate and mean sea level variations in the dynamics of a coastal spit over the last 250 years: Cap Ferret,SW France

In coastal areas, sea level rise (SLR) and changing wave climates are expected to be the main oceanic drivers of shoreline adjustments. These drivers have been shown to vary on a wide spectrum of spatial and temporal scales. Nonetheless, a general rule about how this variability impacts global shorelines remains to be articulated. Here, we discuss the impacts of wave climate changes and SLR on the evolution of a barrier spit–inlet system over the last 250 years. The distal end of the Cap Ferret barrier spit, SW France, has undergone large-scale oscillations that were well correlated with variations of the decadal average of the winter North Atlantic Oscillation (NAO) index. The local wave climate hindcast supports that increased alongshore wave energy fluxes associated with the positive phase of the NAO were responsible for the updrift retreat of the spit. By opposition, the spit has elongated downdrift when waves were less energetic and more shore normal, as during the negative phase of the NAO. In addition, lower rates of SLR appeared to be necessary for the spit to develop, as higher rates of SLR very likely forced the adjacent inlet to enlarge, at the expense of the spit. These results should help to predict and detect coastal adjustments driven by climate change and by climate variability. © 2019 John Wiley & Sons, Ltd.     

Assessment of Hurricane Ivan impact on chlorophyll-a in Pensacola Bay by MODIS 250 m remote sensing

The impact of Hurricane Ivan on water quality in Pensacola Bay was investigated by MODIS 250 m remote sensing of chlorophyll-a concentrations at different time slots before and after the hurricane event. Before the hurricane, the mean chlorophyll-a in the Bay was 5.3 μg/L. Heavy rainfall occurred during the hurricane landfall. The 48 h rainfall reached 40 cm and the peak storm surge reached 3 m on 9/16. After the rainstorm and during the storm surge on 9/17/2004, the mean chlorophyll-a concentration substantially increased to 14.7 μg/L. 26.3% water area was in the poor-water-quality condition (chl-a > 20 μg/L). This indicates that heavy nutrient loads from urban stormwater runoff and storm-surge inundation simulated chlorophyll bloom. After the end of the storm surge on 9/18/2004, the mean chlorophyll dropped to 2.0 μg/L, suggesting the effective flushing of polluted water from the bay to the Gulf of Mexico by the storm-surge. The good water quality condition lasted for almost several weeks after the storm surge. The peak river flow, arriving on the 4th day after the peak storm surge, did not alter the good water quality situation in the bay. This indicates that urban stormwater runoff rather than the river inflow is the major pollutant source for water quality in Pensacola Bay during the hurricane.     

GLUE: 20 years on

This paper reviews the use of the Generalized Likelihood Uncertainty Estimation (GLUE) methodology in the 20 years since the paper by Beven and Binley in Hydrological Processes in (1992), which is now one of the most highly cited papers in hydrology. The original conception, the on‐going controversy it has generated, the nature of different sources of uncertainty and the meaning of the GLUE prediction uncertainty bounds are discussed. The hydrological, rather than statistical, arguments about the nature of model and data errors and uncertainties that are the basis for GLUE are emphasized. The application of the Institute of Hydrology distributed model to the Gwy catchment at Plynlimon presented in the original paper is revisited, using a larger sample of models, a wider range of likelihood evaluations and new visualization techniques. It is concluded that there are good reasons to reject this model for that data set. This is a positive result in a research environment in that it requires improved models or data to be made available. In practice, there may be ethical issues of using outputs from models for which there is evidence for model rejection in decision making. Finally, some suggestions for what is needed in the next 20 years are provided. © 2013 The Authors. Hydrological Processes published by John Wiley & Sons, Ltd.     

Fifty years of stacking

Common-Mid-Point (CMP) stacking is a major process to enhance signal-to-noise ratio in seismic data. Since its appearance fifty years ago, CMP stacking has gone through different phases of prosperity and negligence within the geophysical community. During those times, CMP stacking developed from a simple process of averaging into a sophisticated process that involves complicated mathematics and state-of-the-art computation. This article summarizes the basic principles, assumptions, and violations related to the CMP stacking technique, presents a historical overview on the development stages of CMP stacking, and discusses its future potentiality.     

Geomagnetic evolution: 400 years of change on planet Earth

Spherical harmonic coefficients of the geomagnetic field, calculated from historical observations of declination, inclination and intensity, and from archaeomagnetic inclination results, have been used to produce a film of geomagnetic change since 1600 A.D. The non-dipole geomagnetic field is found to be constantly changing: no fixed or standing non-dipole features are observed. Non-dipole foci are seen to have lifetimes of a few hundred years. The westward drift, which was an important feature of the 18th and early 19th century geomagnetic field, was less pronounced in the 17th century. The growth, evolution, decay and replacement of non-dipole foci, but not their movement are found to have been the major features producing century-long secular directional magnetic variation. Most of the low degree and order spherical harmonic coefficients have changed significantly over the last few hundred years. In particular the change in sign of the axisymmetric quadrupole around 1837 A.D. is noted. Sustained, century-long, intensity changes, however, appear to have been dominated by variations in the intensity of the centred dipole, rather than by non-dipole field fluctuations.     

Solar activity and climatic variability in the time interval from 10 to 250 Ma ago

The climatic variability in the past on the time scales from several tens to several hundreds of million years has been analyzed based on the paleoclimatic data with a time resolution of several years (the variations in the fossil tree ring widths, varve). The revealed periodicity in the climatic parameters correlates with the observed solar activity cyclicity, which indicates that this periodicity effectively influences climate changes independently of differences in the climatic conditions in the considered interval.     

庆祝《CT理论与应用研究》杂志创刊15周年暨公开发行十周年纪念会和有奖征文启事

在新的世纪来临之际，《CT理论与应用研究》杂志，1987年创刊，已15周年。自1992年1月经国家科委批准为国内外发行的中央级科技期刊，至今已在国内外发行十年。国际标准刊号为ISSN 1004-4140，国内统一刊号为CN11-3017/P。本刊特邀国内外知名人士为顾问，有国际体视学学会主席John F. Bertram 教授, S.J.Duda教授(德国汉堡大学) 香港顾问：吴敬文、罗吴美英(英国医学院院士)。国内：地球物理专家陈运泰院士、陈 顒院士、何继善院士；刘赓年教授、徐家兴教授、戴汝平教授等有关CT、MRI方面的医学知名专家等任顾问。 从1993年起,本刊在地震联合基金办公室的领导下,得到科技日报、中国科协报的支持下，连续七年举办了“亚洲CT科技十大进展和中国CT科技新进展评选与信息交流会”，有人民日报(海外版)、科技日报、大众科技报等八家报刊给予了报道。在亚洲地区，CT科技已在医学临床诊断方面得到迅速的发展，并很快在地震CT探查震源破裂过程及其环境、地球资源和能源的探测、检测矿山崩塌、用γ-射线背散射对炸药和毒品作安全保卫检测、土木、水利工程的地基稳定性检测、工业CT对精密零件的无损检测、用γ-射线探测房屋和厂房结构、用地电、电磁CT探测地下水、古文物探测等方面发挥了重要的作用。为了进一步加快高性能CT科技的发展，交流在国际上发展CT和三维成像的理论、应用技术的成就和展望。中国科协国际部同意，由中国体视学学会在北京市举办“国际CT和三维断面成像理论与应用学术会议”，并已得到中国科学技术部的批准。邀请到X-CT机的发明家Dr.G.Hounsfield(英国,1979年Nobel奖金得主)任大会名誉主席，国家自然科学基金委原副主任孙枢院士担任名誉主席，现任副主任王乃彦院士和深圳大学谢维信校长任大会主席。本刊为主要的承办单位。2000年10月5日在天安门人民大会堂举行了开幕式；特请Bertram教授，So Gu Kim教授、归来、郑全录、丁厚本、潘玉玲教授和底青云博士等专家做了大会特邀报告。“CT与三维成像展览会”在北苑宾馆隆重剪彩开幕，有12个展台，展示了三维成像图片、实物样机、和在计算机里储存的若干CT科技成果和统计资料。会议共收到中国，澳大利亚、日本、韩国、俄罗斯、英国、美国和芬兰等国学者的学术论文、报告85篇。会议以中英文对照方式出版了论文集《CT理论与应用研究2000年第9卷增刊》,在国内外公开发行、正式引用。根据国家社会力量设立科学技术奖的文件精神，本次会议设立了“体视学和CT成像荣誉奖章和奖杯”，以及优秀论文证书。由于这次会议的成功，国际体视学学会决定2003年在北京召开第XI届国际体视学大会亚太地区卫星式学术会议。     

Eighteen years of observations on the Fennoscandian land uplift gravity lines

In order to investigate the variation in gravity caused by the Fennoscandian land uplift, the Nordic countries have established 4 profiles with near-zero gravity differences along the latitudes 65°, 63°, 61° and 56° N. High-precision gravity measurements have been repeatedly made on these lines since 1975, 1966, 1976 and 1977, respectively. The observations have recently been published in one volume.     

Dambreak flood impact on mountain stream bedload transport after 13 years

Studies of the bedload transport regime of the Roaring River, Colorado, in 1984–88, following a dambreak flood in 1982, showed that bedload transport rates were an order of magnitude higher than under pre-flood conditions. A gorge eroded by the flood in glacial moraine acted as a major sediment supply source. Measurements in early June 1995 showed a continued potential for high sediment supply from the gorge and a bedload transport regime similar to that of 1984–88. A major snowmelt flood in mid-June flushed sediment supplies from the gorge and measurements in July showed a corresponding reduction in bedload transport. However, high sediment supply will continue until the gorge cliffs revegetate or erode to a stable slope. The measurements demonstrate both the control exercised by sediment supply on transport rates and the persistent long-term impact of major floods on mountain streams. © 1998 John Wiley & Sons, Ltd.