Response of a bounded atmosphere to a non-resonant excitation     

Janine Provost 《Solar physics》1975,40(2):257-273

The response of a bounded atmosphere to a non-resonant excitation applied at its basis is studied. It is shown that the essential feature related to this kind of excitation is that the distribution of the energy of the velocity field relatively to the frequency and horizontal wavelength is a function of height and merely depends on the structure of the atmosphere above the level at which it is considered. The preliminary results concerning an isothermal atmosphere are presented and their relevance to the solar case is discussed.  相似文献   

Narrative analysis as a strategy for understanding interview talk in geographic research   总被引：1，自引：0，他引：1  

Janine L Wiles  Mark W Rosenberg  Robin A Kearns 《Area》2005,37(1):89-99

Narrative analysis produces strategies to inform the conduct, interpretation and presentation of interview talk, and encourages and enables researchers to take account of research participants' own evaluations. We suggest this to be a useful method for geographers because it focuses on how people talk about and evaluate places, experiences and situations, as well as what they say. With an example from health geography, we show how it allows for interactive texts, thus providing a tool for geographers doing qualitative research to connect intimate details of experience to broader social and spatial relations.  相似文献   

Wave reflections in the solar atmosphere     

Janine Provost  Nicole Mein 《Solar physics》1979,64(1):43-56

The small phase-lag between velocities observed at different chromospheric levels is interpreted as being due to acoustic waves reflected by the very hot atmospheric layers of the chromosphere-corona transition zone. We consider first an isothermal slab, then a realistic solar atmospheric model and calculate weighting functions for velocities in Ca ii lines. It is shown that taking into account these functions and integrating over horizontal wave numbers leads to a good agreement with previous observations (Mein, 1977) in the case of 8498 and 8542 Ca ii lines. For the K line, the less good agreement shows that magnetoacoustic waves become important in the upper chromospheric layers.  相似文献   

⁴⁰Ar/³⁹Ar ages for the alkaline volcanism and the basement of Gorringe Bank,North Atlantic ocean     

Gilbert Féraud  Janine Gastaud  Jean-Marie Auzende  Jean-Louis Olivet  Guy Cornen 《Earth and Planetary Science Letters》1982,57(1):211-226

Gorringe Bank is situated on the Europe-Africa plate boundary at the eastern end of the Azores-Gibraltar fracture zone. It has two summits, Gettysburg Bank to the Southwest and Ormonde Bank to the northeast.We applied the⁴⁰Ar/³⁹Ar stepwise heating method to date six samples of the alkaline volcanic rocks, two gabbros from the Ormonde Bank and a dolerite from the Gettysburg Bank. The results that the alkaline volcanism lasted probably for less than 6 Ma(66-60 Ma).Although the nature of this volcanism precludes any subduction feature during its setting, the alkaline volcanism of Ormonde is probably linked to Upper Cretaceous/Eocene compressive tectonic events.The basement rocks of Gorringe Bank reveal distrubed⁴⁰Ar/³⁹Ar age spectra. One plagioclase and one biotite from a gabbro give evidence for a thermic event whose age is tentatively estimated at about 75 Ma, and related to a variation in the direction of the relative movement between Europe and Africa. The more probable age given by a plagioclase of another gabbro and by a dolerite (110 Ma) corresponds to tilting northeastward of the Gorringe massif.  相似文献   

VIRGO: Experiment for helioseismology and solar irradiance monitoring   总被引：1，自引：0，他引：1  

Claus Fröhlich  José Romero  Hansjörg Roth  Christoph Wehrli  Bo N. Andersen  Thierry Appourchaux  Vicente Domingo  Udo Telljohann  Gabrielle Berthomieu  Philippe Delache  Janine Provost  Thierry Toutain  Dominique A. Crommelynck  André Chevalier  Alain Fichot  Werner Däppen  Douglas Gough  Todd Hoeksema  Antonio Jiménez  Maria F. Gómez  José M. Herreros  Teodoro Roca Cortés  Andrew R. Jones  Judit M. Pap  Richard C. Willson 《Solar physics》1995,162(1-2):101-128

The scientific objective of the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) is to determine the characteristics of pressure and internal gravity oscillations by observing irradiance and radiance variations, to measure the solar total and spectral irradiance and to quantify their variability over periods of days to the duration of the mission. With these data helioseismological methods can be used to probe the solar interior. Certain characteristics of convection and its interaction with magnetic fields, related to, for example, activity, will be studied from the results of the irradiance monitoring and from the comparison of amplitudes and phases of the oscillations as manifest in brightness from VIRGO, in velocity from GOLF, and in both velocity and continuum intensity from SOI/MDI. The VIRGO experiment contains two different active-cavity radiometers for monitoring the solar constant, two three-channel sunphotometers (SPM) for the measurement of the spectral irradiance at 402, 500 and 862 nm, and a low-resolution imager (LOI) with 12 pixels, for the measurement of the radiance distribution over the solar disk at 500 um. In this paper the scientific objectives of VIRGO are presented, the instruments and the data acquisition and control system are described in detail, and their measured performance is given.died 13 October 1994  相似文献   

Certification of ERM‐EB400, the First Matrix Reference Material for Lead Isotope Amount Ratios,and ERM‐AE142, a Lead Solution Providing a Lead Isotopic Composition at the Edge of Natural Variation     

Jochen Vogl  Yong‐Hyeon Yim  Kyoung‐Seok Lee  Heidi Goenaga‐Infante  Dmitriy Malinovskiy  Sarah Hill  Tongxiang Ren  Jun Wang  Robert D. Vocke  Karen E. Murphy  Naoko Nonose  Olaf Rienitz  Janine Noordmann 《Geostandards and Geoanalytical Research》2019,43(1):23-37

Lead isotope amount ratios are commonly used in diverse fields such as archaeometry, geochemistry and forensic science. Currently, five reference materials with certified lead isotope amount ratios are available, namely NIST SRM 981, 982 and 983, GBW‐04442 and NMIJ 3681‐a. Only NIST SRM 981 and NMIJ 3681‐a have approximately natural isotopic compositions, and NIST SRM 981 is predominantly used for correcting mass discrimination/mass fractionation in the applied mass spectrometric procedures. Consequently, there is no other certified reference material available to be used for validation and/or quality control of the analytical procedures applied to lead isotope amount ratio measurements. To fill this gap, two new reference materials have been produced and certified for their lead isotope amount ratios. For both certified reference materials, complete uncertainty budgets have been calculated and SI traceability has been established. This provides the users with independent means for validating and verifying their analytical procedures and for conducting quality control measures. ERM‐EB400 is a bronze material with a nominal lead mass fraction of 45 mg kg^?1 and certified lead isotope amount ratios of n(²⁰⁶Pb)/n(²⁰⁴Pb) = 18.072(17) mol mol^?1, n(²⁰⁷Pb)/n(²⁰⁴Pb) = 15.578(18) mol mol^?1 and n(²⁰⁸Pb)/n(²⁰⁴Pb) = 38.075(46) mol mol^?1 with the associated expanded uncertainties (k = 2) given in brackets. ERM‐AE142 is a high‐purity solution of lead in 2% nitric acid with a nominal mass fraction of 100 mg kg^?1 and certified Pb isotope amount ratios of n(²⁰⁶Pb)/n(²⁰⁴Pb) = 21.114(17) mol mol^?1, n(²⁰⁷Pb)/n(²⁰⁴Pb) = 15.944(17) mol mol^?1 and n(²⁰⁸Pb)/n(²⁰⁴Pb) = 39.850(44) mol mol^?1 with the associated expanded uncertainties (k = 2) given in brackets. Both materials are specifically designed to fall within the natural lead isotopic variation and to assist users with the validation and verification of their analytical procedures. Note that while one of these reference materials requires the chemical separation of Pb from its matrix (ERM‐EB400), the other does not (ERM‐AE142). As additional information, δ^208/206Pb_{NIST SRM981} values are provided for both materials. For ERM‐AE142, a delta value of δ^208/206Pb_{NIST SRM981} = ?28.21(30)‰ was obtained, and for ERM‐EB400, a delta value of δ^208/206Pb_NIST SRM981= ?129.47(38)‰ was obtained, with the associated expanded uncertainties (k = 2) given in brackets.  相似文献   

The volatile content of hypabyssal kimberlite magmas: some constraints from experiments on natural rock compositions   总被引：1，自引：0，他引：1  

Richard A. Brooker  R. Stephen J. Sparks  Janine L. Kavanagh  Matthew Field 《Bulletin of Volcanology》2011,73(8):959-981

Kimberlites are volatile rich magmas that ascend from deep in the mantle at high velocities, then as they reach a ‘root zone’ at 1–3 km in depth they either discharge explosively through to the surface or stall to form dykes and sills. Understanding this eruptive behaviour is difficult due to a lack of data on volatile solubility, particularly at conditions where the magmas enter the ‘root zone’ (∼30–80 MPa). In this study, we perform experiments on some putative primary kimberlite magma compositions to assess the amount of CO₂ and H₂O retained if these compositions represent magma as it enters the root zone. At the conditions investigated (100–200 MPa and 1,275–1,100°C) the results suggest that none of these particular kimberlite compositions reproduce a magma that can retain the observed high volatile content when intruded at these pressures (∼4–8 km). In our experiments, the low volatile retention is due to a combination of factors including a high proportion of solid phases, none of which are volatile-bearing, and inadequate volatile solubilities in the subordinate amounts of melt present. Modelled solubilities also suggest that the dissolved volatile contents remain too low even at super-liquidus temperatures (i.e. 100% melt). For water, the higher values observed in natural rocks can be explained by the addition of H₂O associated with ubiquitous post-emplacement serpentinization. The high CO₂ contents in hypabyssal rocks are unlikely to be related to alteration. We suggest that most kimberlites originally had lower SiO₂ contents and as such may have been ‘transitional’ between silicate and carbonate melts. This results in both higher CO₂ solubilities and lower liquidus temperatures. For such compositions, it is possible that both CO₂ and water solubility may first decrease and then increase as magmas decompress and crystallize. Such unusual behaviour can help explain why kimberlite magmas can be very explosive or form shallow hypabyssal intrusions.  相似文献   

Approaches to human geography: Philosophies,theories, people and practices          下载免费PDF全文

Janine Wiles 《New Zealand geographer》2016,72(1):76-77

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Evaluation and modelling of Tertiary source rocks in the central Arctic Ocean     

Ute Mann  Jochen Knies  Shyam Chand  Wilfried Jokat  Ruediger Stein  Janine Zweigel   《Marine and Petroleum Geology》2009,26(8):1624-1639

With the recently recovered organic-rich sediments of early Tertiary age from the Lomonosov Ridge by the Integrated Ocean Drilling Program (IODP) Expedition 302, the first data collection directly from source rocks of the central basins of the Arctic Ocean is now available. Using the results of seismic interpretations and published sedimentological and organic geochemical data from Expedition 302, the framework for the first quantitative assessment of source-rock quality and distribution of the Palaeogene sediments was modelled in the central Arctic Ocean. The modelling results suggest that an approximately 100-m-thick Early to Middle Eocene sedimentary sequence of good to very good source rocks exists along a 75 km long transect across the Lomonosov Ridge. In-situ generation of hydrocarbons is unlikely because the overburden (200–250 m) and consequently the thermal maturity are too low. Burial history and thermal modelling reveal that an additional overburden of at least 1000 m is necessary to start hydrocarbon generation along the ridge. However, source-rock modelling results show that good source-rock potential may exist in correlative units in the adjacent Amundsen Basin. Simulated organic carbon contents of 1.5–5%, coupled with an overburden of 1000–1200 m, and heat flow anomalies (117 and 100 mW m⁻²) due to the vicinity to the Gakkel Ridge spreading centre indicate that necessary conditions for hydrocarbon expulsion are already reached, and point to viability of a potential petroleum system. Our results support the hypothesis that deposition of a potentially good hydrocarbon source rock occurred across the entire Arctic Basin and adjacent margins during the early Tertiary.  相似文献   

Culture/Place/Health     

Janine Wiles 《New Zealand geographer》2002,58(2):79-79

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