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

{"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":"Photochemical activity over the eastern mediterranean under variable environmental conditions","authors":"C.S. Zerefos ,&nbsp;K.A. Kourtidis ,&nbsp;D. Balis ,&nbsp;A. Bais ,&nbsp;B. Calpini","doi":"10.1016/S1464-1917(01)00045-9","DOIUrl":"10.1016/S1464-1917(01)00045-9","url":null,"abstract":"<div><p>The present paper presents some of the results from the EU-funded Photochemical Activity and solar Ultraviolet Radiation (PAUR) and Photochemical Activity and solar Ultraviolet Radiation Modulation Factors (PAUR II) projects that are relevant to the photochemistry of the Eastern Mediterranean under variable conditions. Compared to S-SW flows, northern flows result in higher ozone values above the PBL. Usually during N flow the aerosol optical depth is also lower, thus resulting in higher NO₂ photodissociation rates. In one case of northern flow, the Etesian synoptic regime, N-NE flows are associated with high wind speeds and result to even lower aerosol optical depth. S-SW flow during springtime in some cases brings air loaded with Saharan dust particles over the region that is poor in tropospheric ozone and precursors. Often, these cases are associated with southern stratospheric circulation, resulting in reduced total ozone amounts and hence increased ozone photolysis rates, whereas the dust load reduces nitrogen dioxide photolysis rates. Results are presented from a spectral radiation model, which simulates the spectral UV radiation during some of the above cases. Measurement results from the Athens basin and rural Aegean sites are presented, that compare the ozone levels between normal N flow conditions and Etesian flow.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 7","pages":"Pages 549-554"},"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)00045-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79219203","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":"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":"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":"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":"Electromagnetic signals of a seismic excitation of geolocal structures beneath a sea bottom","authors":"S.V. Ershov ,&nbsp;I.B. Mikhaylovskaya ,&nbsp;O.B. Novik","doi":"10.1016/S1464-1917(01)95022-6","DOIUrl":"10.1016/S1464-1917(01)95022-6","url":null,"abstract":"<div><p>We formulate a mathematical model of generation and propagation of seismo-electromagnetic (EM) signals in the basin of a marginal sea with an arbitrary 2D geological structure of the bottom, including the transfer of seismic and EM energy from lithosphere to hydrosphere and EM emission into atmosphere. In case of a model basin which is a 2D scheme of the central part of the basin of the Sea of Japan, the first magnetic signal is generated in the conductive (0.02 S/m) upper mantle layer M where weak seismic displacements (SD) are supposed to arise at the moment <em>t</em> = 0. The amplitude and duration of a SD were of order of a few centimetres and a few seconds and differ in different simulations. The primary signal from M with the amplitude about 50 pT reaches for the sea bottom at the moment <em>t</em> = 3.5 sec. Magnetic diffusion into the conductive sea water is too slow and thus EM signal in atmosphere originates due to geomagnetic field induction in the vertically moving water column Q_s located above the area of the initial contact of the seismic P wave (from M) with the sea bottom. Because of the structure of the seismo-hydrodynamic field and the EM field conjugation conditions at the sea-atmosphere interface the horizontal component <em>B₂</em> of the seismo-hydrodynamic magnetic field is being generated, at first, in a thin water layer under the top of <em>Q</em>_s at the sea surface, whereas the vertical component <em>B</em>₁ is being generated everywhere in <em>Q</em>_s. After the spreading of the magnetic signals, <em>B</em>₁ is up to 250 and 150 pT at the sea surface and at the height of 10 km respectively at <em>t</em> = 10 sec Magnetic signals are represented by oscillations of the same low frequency range (0.1 to 10 Hz) as the SD. The computed long hydrodynamic wave's amplitude, caused by the SD, is not more then 20 cm. Therefore the waves transferring seismic energy can be discovered far from the coast by low-frequency EM observations.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 10","pages":"Pages 761-768"},"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)95022-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80749105","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}

{"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":"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}