Solar-cycle variation of the sound-speed asphericity from GONG and MDI data 1995–2000     

H.M. Antia  S. Basu  F. Hill  R. Howe  R.W. Komm  J. Schou 《Monthly notices of the Royal Astronomical Society》2001,327(3):1029-1040

We study the variation of the frequency splitting coefficients describing the solar asphericity in both GONG and MDI data, and use these data to investigate temporal sound-speed variations as a function of both depth and latitude during the period 1995–2000 and a little beyond. The temporal variations in even splitting coefficients are found to be correlated to the corresponding component of magnetic flux at the solar surface. We confirm that the sound-speed variations associated with the surface magnetic field are superficial. Temporally averaged results show a significant excess in sound speed around     and latitude of 60°.  相似文献   

Influences of Natural and Anthropogenic Factors and Tidal Restoration on Terrestrial Arthropod Assemblages in West Coast North American Estuarine Wetlands     

Aaron T. David  Pascale A. L. Goertler  Stuart H. Munsch  Brittany R. Jones  Charles A. Simenstad  Jason D. Toft  Jeffery R. Cordell  Emily R. Howe  Ayesha Gray  Michael P. Hannam  William Matsubu  Erin E. Morgan 《Estuaries and Coasts》2016,39(5):1491-1504

Compared to benthic and water-column invertebrate assemblages, considerably less is known about terrestrial arthropods inhabiting estuarine wetlands despite their importance to tidal wetland biodiversity and productivity. We also need to know more about how human modification of estuaries, including efforts to restore estuarine wetlands, affects these assemblages. To address this knowledge gap, we assembled data from multiple studies on terrestrial arthropod assemblages from 87 intertidal wetland sites in 13 estuaries along the west coast of North America. Arthropods were sampled between 1998 and 2013 with fallout traps deployed in wetlands for 1 to 3 days at a time. We describe patterns in the abundance and taxonomic composition of terrestrial arthropods and evaluate the relative ability of natural and anthropogenic factors to explain variation in abundance and composition. Arthropod abundance was highly variable. Vegetation assemblage, precipitation, and temperature best explained variation in arthropod abundance, while river discharge, latitude, and developed and agricultural land cover surrounding sampling sites were less important. Arthropod abundance rapidly achieved levels of reference wetlands after the restoration of tidal influence to leveed wetlands, regardless of surrounding land cover. However, arthropod assemblage composition was affected by the amount of developed land cover as well as restoration age. These results suggest that restoration of tidal influence to leveed wetlands can rapidly restore some components of estuarine wetland ecosystems but that recovery of other components will take longer and may depend on the extent of anthropogenic modification in the surrounding landscape.  相似文献   

Performance of the Birmingham Solar-Oscillations Network (BiSON)     

S. J. Hale  R. Howe  W. J. Chaplin  G. R. Davies  Y. P. Elsworth 《Solar physics》2016,291(1):1-28

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Stream-coordinate structure and variability of the Kuroshio Extension     

Penelope J. Howe  Kathleen A. Donohue  D. Randolph Watts 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(7):1093-1116

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Habitat utilization by postlarval and juvenile penaeid shrimps in Mobile Bay, Alabama     

Jeffrey C. Howe  Richard K. Wallace  F. Scott Rikard 《Estuaries and Coasts》1999,22(4):971-979

Densities of juvenile and postlarval Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus were compared in vegetated fringing marsh and adjacent nonvegetated areas over a range of environmental conditions in Mobile Bay, Alabama. Densities of all three species were significantly greater in vegetated than nonvegetated areas, with 82% of all penaeids found in vegetated areas. Among vegetated sites, significantly lower densities were found in oligohaline areas, whereas mesohaline areas had the highest densities. Significant positive correlations were found between density and salinity for F. aztecus and F. duorarum but not for L. setiferus. Emergent vegetation is important habitat for F. aztecus and F. duorarum as reported from other locations, and our data support a similar conclusion for L. setiferus. Shoreline emergent marsh vegetation is particularly important in Mobile Bay as it represents the only extensive vegetated habitat readily available to F. aztecus, F. duorarum, and L. setiferus.  相似文献   

A physical and chemical description of the Mediterranean outflow in the Gulf of Cadiz     

I. Ambar  M. R. Howe  M. I. Abdullah 《Ocean Dynamics》1976,29(2):58-68

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Local community training and education in southern Tanzania—a case study     

Vicki Howe   《Marine Policy》2001,25(6)

Local coastal communities are highly dependent upon the marine environment not only for protein but also as a primary source of income. In addition, there are growing economic opportunities offered within the coastal zone. As populations increase in these areas there is an increasing demand on coastal resources. This in turn requires effective management initiatives at regional, national and local levels.The Marine Education and Training Programme in Mtwara, southern Tanzania was a small scale capacity building project that incorporated two elements; a primary schools field day education programme and a marine coastal resources course for fishermen and women from the Mtwara District. The programme ran for a period of 1 year and during that time 14 schools, 198 children, 34 fishermen, 2 women and 14 villages participated. Results from preliminary evaluation indicated that such education is not only welcome by the local government offices, teachers, village chairmen and fishermen as an expansion of the knowledge base, but is also an important and valuable stepping stone for the local communities to become active in issues regarding the management of coastal resources.  相似文献   

A review of recent results on ocean acoustic wave propagation inrandom media: basin scales     

Colosi  J.A. Baggeroer  A.B. Birdsall  T.G. Clark  C. Cornuelle  B.D. Costa  D. Dushaw  B.D. Dzieciuch  M.A. Forbes  A.M.G. Howe  B.M. Menemenlis  D. Mercer  J.A. Metzger  K. Munk  W. Spindel  R.C. Worcester  P.F. Wunsch  C. 《Oceanic Engineering, IEEE Journal of》1999,24(2):138-155

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Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data   总被引：1，自引：1，他引：0  

Cuong V. A. Le  Brett D. Harris  Andrew M. Pethick  Eric M. Takam Takougang  Brendan Howe 《Surveys in Geophysics》2016,37(5):845-896

Natural source electromagnetic methods have the potential to recover rock property distributions from the surface to great depths. Unfortunately, results in complex 3D geo-electrical settings can be disappointing, especially where significant near-surface conductivity variations exist. In such settings, unconstrained inversion of magnetotelluric data is inexorably non-unique. We believe that: (1) correctly introduced information from seismic reflection can substantially improve MT inversion, (2) a cooperative inversion approach can be automated, and (3) massively parallel computing can make such a process viable. Nine inversion strategies including baseline unconstrained inversion and new automated/semiautomated cooperative inversion approaches are applied to industry-scale co-located 3D seismic and magnetotelluric data sets. These data sets were acquired in one of the Carlin gold deposit districts in north-central Nevada, USA. In our approach, seismic information feeds directly into the creation of sets of prior conductivity model and covariance coefficient distributions. We demonstrate how statistical analysis of the distribution of selected seismic attributes can be used to automatically extract subvolumes that form the framework for prior model 3D conductivity distribution. Our cooperative inversion strategies result in detailed subsurface conductivity distributions that are consistent with seismic, electrical logs and geochemical analysis of cores. Such 3D conductivity distributions would be expected to provide clues to 3D velocity structures that could feed back into full seismic inversion for an iterative practical and truly cooperative inversion process. We anticipate that, with the aid of parallel computing, cooperative inversion of seismic and magnetotelluric data can be fully automated, and we hold confidence that significant and practical advances in this direction have been accomplished.  相似文献   

North east pacific time-integrated undersea networked experiments (NEPTUNE): cable switching and protection     

El-Sharkawi  M.A. Upadhye  A. Shuai Lu Kirkham  H. Howe  B.M. McGinnis  T. Lancaster  P. 《Oceanic Engineering, IEEE Journal of》2005,30(1):232-240

The objective of the North East Pacific Time-Integrated Undersea Networked Experiments (NEPTUNE) is to establish a permanent, subsea observatory surrounding the Juan de Fuca tectonic plate. To achieve this objective, a special power distribution system is designed to provide continuous power to science equipment, vehicles, and laboratories located as deep as 5 km below the water surface. The NEPTUNE power system is significantly different from terrestrial power systems in many aspects and it requires different switching, protection, and control strategies. In this paper, we address the design of system switching and fault isolation equipment.  相似文献