Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science最新文献

{"title":"Electric and magnetic fields generated by electrokinetic processes in a conductive crust","authors":"E. Fedorov ,&nbsp;V. Pilipenko ,&nbsp;S. Uyeda","doi":"10.1016/S1464-1917(01)95027-5","DOIUrl":"10.1016/S1464-1917(01)95027-5","url":null,"abstract":"<div><p>The results of different models of electrokinetic sources of ULF disturbances, mostly based on numerical calculations, can be reproduced with a much simpler analytical model of an elliptic-shaped inhomogeneity. The suggested model can be applied to the estimates of electromagnetic fields from elementary sources of different geometries. Moreover, this model enables one to estimate the screening effect of the back conductivity currents and the influence of the ground-atmosphere boundary. The estimates show that the expected magnitudes of seismo-electromagnetic signals in ULF band from an elementary electrokinetic source may reach the detection level only for rather favorable set of crustal parameters.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 10","pages":"Pages 793-799"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)95027-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78376553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of the auroral particle acceleration in the upward and downward current regions","authors":"G.T. Marklund,&nbsp;T. Karlsson","doi":"10.1016/S1464-1917(00)00094-5","DOIUrl":"10.1016/S1464-1917(00)00094-5","url":null,"abstract":"<div><p>To understand auroral particle acceleration it is necessary to consider the entire auroral current circuit, from the generator in the outer magnetosphere to the auroral ionosphere, decoupled from each other by field-aligned potential drops in both the upward and downward current regions. This paper focusses on the characteristics of such potential drops responsible for the accelerated electrons that produce the aurora and for the upward acceleration of ions and electrons. First, some features of the converging electric field structures in the upward current region are discussed based predominantly on results from Viking observations within and above the acceleration region. These include the relationship between the high-altitude potential and the ionospheric potential associated with auroral arcs; ways to estimate the field-aligned potential drop from in situ satellite measurements of fields and particles; the role of low-frequency electric field fluctuations for acceleration and heating of auroral particles. A brief review is then given of recent Freja results on characteristics of the downward current region, such as the intense diverging electric field structures that give rise to upward acceleration of ionospheric electrons and perpendicular ion heating. Different theoretical models have been proposed to explain these phenomena. It is clear that the plasma density on auroral field lines and the ionospheric density play a fundamental role for where and when potential structures are formed in the upward and downward current region. For a current generator feeding the auroral currents, particle acceleration is necessary to maintain the current through regions of low plasma density. The altitude distribution of the field-aligned potential will thus depend strongly on the local ambient plasma conditions, and thus vary with local time, season and magnetic activity level. These characteristics could be investigated in detail by combining measurements from various spacecraft (such as Viking, Polar, Freja, FAST, and Astrid-2) at different altitudes with respect to the the field-aligned potential distribution.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 81-96"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(00)00094-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77096904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Options for coordinated multi-point sensing in the lower thermosphere","authors":"E.J. van der Heide ,&nbsp;J.A. Carroll ,&nbsp;M. Kruijff","doi":"10.1016/S1464-1917(00)00122-7","DOIUrl":"10.1016/S1464-1917(00)00122-7","url":null,"abstract":"<div><p>A satellite mission for synchronized multi point measurements over tens of km in the lower thermosphere is possible at low cost and in a short time frame. This paper offers three options for providing coordinated multi-point sensing in the lower thermosphere. The options have quite different implications and idiosyncrasies, and possibly quite different costs and values. We invite members of the thermospheric research community to provide feedback on these concepts and how they might be used to best advantage.</p><p>The authors have experience with proposing and pursuing small satellite missions, especially using space tether technology. Tether Applications has developed and delivered SEDS hardware for 3 successful orbital flight tests of tethers. Delta-Utec is specialized in deployment algorithms and has proposed and developed the tethered YES satellite.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 4","pages":"Pages 285-291"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(00)00122-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77184656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictions for the propagation of energetic particles from the sun to the earth: influence of the magnetic turbulence","authors":"G. Zimbardo,&nbsp;P. Pommois,&nbsp;P. Veltri","doi":"10.1016/S1464-1917(01)00053-8","DOIUrl":"10.1016/S1464-1917(01)00053-8","url":null,"abstract":"<div><p>Energetic particle fluxes in the Earth's magnetosphere can seriously affect spacecraft operations as well as navigation and communication systems. To this end, and critical issue is to understand and predict whether particles accelerated at a solar flare will impinge on the Earth's magnetosphere. Energetic particle propagation depends on the magnetohydrodynamic turbulence in the solar wind. We present here a Monte Carlo simulation which traces the magnetic field line from the Earth to the solar corona, taking into account both the average Parker spiral magnetic field and the effects of magnetic turbulence. A proper evaluation of the diffusion coefficient is obtained by a numerical simulation of transport in anisotropic magnetic turbulence which takes into account the scaling of the fluctuation level and of the correlation lengths with the distance from the Sun. This numerical code allows to determine, from the observations of a solar flare at given heliographic latitude and longitude, whether energetic particles will come over the magnetosphere or not.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 8","pages":"Pages 595-599"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00053-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77186546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeological monitoring and image analysis of a mudslide in Southern Italy","authors":"M. Polemio ,&nbsp;O. Petrucci","doi":"10.1016/S1464-1917(01)00068-X","DOIUrl":"10.1016/S1464-1917(01)00068-X","url":null,"abstract":"<div><p>This paper describes a methodological example of a data-integration procedure to improve the knowledge of landslide hazard related to a seismic area in the southern Apennine (Italy). Attention is focused on remote sensing data. The analysis is validated using detailed topographical, geophysical, geotechnical and hydrogeological data as <em>ground truth</em>. The investigated phenomenon, which started at the end of 1993, is an earthflow. The presented methodology recommends the combined use of DEM, multi-temporal panchromatic visible aerial photographs and thermal infrared images. The integration between these data and multidisciplinary monitoring data proved useful. The main hydrogeological pattern, the geological and geomorphological framework and the areas of latent instability can be clearly determined. Insight can be gained through the synoptic slope view in the relative short time needed to carry out the analysis. The proposed approach can be regarded as a useful contribution to the evaluation of landslide hazard, particularly during emergency periods.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 9","pages":"Pages 689-695"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00068-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88804700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model assisted inversion of GNSS occultation data","authors":"G. Hochegger,&nbsp;R. Leitinger","doi":"10.1016/S1464-1917(01)00007-1","DOIUrl":"10.1016/S1464-1917(01)00007-1","url":null,"abstract":"<div><p>The classical inversion of occultation data assumes spherical symmetry. Of course in the ionosphere the electron density depends not only on height but also on the geographic coordinates. Projection on a vertical “reconstruction plane” gives dependence of electron density on height and on a horizontal coordinate. Linear horizontal gradients have no influence on inversion results. However, nonlinear gradients (e.g. troughs and ridges) can influence the inversion results in such a way that they differ strongly from true height profiles of electron density in the reconstruction plane.</p><p>We have developed an inversion algorithm which such data driven models constructing the electron density distribution along the occultation rays. This introduces weights into the design matrix of the inversion equation.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 5","pages":"Pages 325-330"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00007-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91261676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Isotope identification in NO as a chemical tracer in the middle atmosphere","authors":"A.C. Aikin","doi":"10.1016/S1464-1917(01)00041-1","DOIUrl":"10.1016/S1464-1917(01)00041-1","url":null,"abstract":"<div><p>The nitrogen isotope ratio of middle atmosphere nitrogen oxide is predicted as a function of altitude. Nitrogen oxides originate photochemically either from stratospheric nitrous oxide reacting with O(¹D) or in the mesosphere and thermosphere from direct dissociation of N₂ and ionization-initiated reactions involving O₂ and N₂. During its formation process, N₂O acquires a nitrogen isotopic composition of N isotopes different than N₂. Photodissociation within the stratosphere also modifies the proportion of isotopes. Reaction of stratospheric NO with O₃ produces NO₂, which when photodissociated yields NO depleted in ¹⁵N relative to NO₂ in laboratory air. The value of δ¹⁵NO in the stratosphere is −100‰. In the altitude region between 50 and 65 km, NO is transformed into NO₂ and then returned to NO by reaction of NO₂ with O and by NO₂ photodissociation. These reactions determine the isotopic makeup of NO. Above 65 km, nitric oxide is produced by local ionization processes and gas phase photochemical reactions involving N₂ and excited O₂. These processes determine the isotopic composition of NO in the upper mesosphere and thermosphere. Here δ¹⁵NO is 0‰. Air transported into the mesosphere above 65 km will reflect the NO isotopic values of the region below, while mesospheric NO transported below 65 km will not be distinguishable from NO originating in the stratosphere.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 7","pages":"Pages 527-532"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00041-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81332586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ESF network on space weather and the earth's weather, SPECIAL","authors":"N.B. Crosby,&nbsp;M.J. Rycroft","doi":"10.1016/S1464-1917(01)00055-1","DOIUrl":"https://doi.org/10.1016/S1464-1917(01)00055-1","url":null,"abstract":"","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 8","pages":"605-607"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00055-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72217830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvement and evaluation of the parameterisation of nitrogen oxide production by lightning","authors":"E.W. Meijer ,&nbsp;P.F.J. van Velthoven ,&nbsp;D.W. Brunner ,&nbsp;H. Huntrieser ,&nbsp;H. Kelder","doi":"10.1016/S1464-1917(01)00050-2","DOIUrl":"https://doi.org/10.1016/S1464-1917(01)00050-2","url":null,"abstract":"","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 8","pages":"577-583"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(01)00050-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72257874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear three-wave interaction of kinetic Alfvén waves (KAW) and particle acceleration in the earth's magnetosphere","authors":"P.P. Malovichko,&nbsp;S.F. Nosov,&nbsp;Yu.V. Kyzyurov","doi":"10.1016/S1464-1917(00)00114-8","DOIUrl":"10.1016/S1464-1917(00)00114-8","url":null,"abstract":"<div><p>In the kinetic approximation, the resonant nonlinear three-wave interaction of Alfvén waves in the Earth's plasmasphere is considered. The nonlinear equations describing evolution of amplitudes of kinetic Alfvén wave packets are obtained. The parametric decay of one KAW into two others is considered. It is shown that such an interaction is very effective, when the kinetic effects exert an essential influence on kinetic Alfvén waves dispersion, and can considerably exceed similar interaction occurring in other areas of the magnetosphere. The nonlinear interaction of a KAW can lead to the generation of a KAW with small enough transverse wave lengths. At an exit from the plasmasphere in an area remoter from the surface of the Earth, such waves will effectively interact with electrons, that will lead to their acceleration and injection into polar areas of the ionosphere.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 237-239"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1917(00)00114-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72513702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}