Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science最新文献_第3页

Natural hazard assessment using GIS and remote sensing methods, with particular reference to the landslides in the Wondogenet Area, Ethiopia 利用地理信息系统和遥感方法进行自然灾害评估，特别是埃塞俄比亚Wondogenet地区的滑坡

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)00065-4

B. Temesgen , M.U. Mohammed , T. Korme

引用次数: 163

Image analysis for debris flow properties estimation 泥石流特性估计的图像分析

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)00059-9

R. Genevois , A. Galgaro , P.R. Tecca

{"title":"Image analysis for debris flow properties estimation","authors":"R. Genevois , A. Galgaro , P.R. Tecca","doi":"10.1016/S1464-1917(01)00059-9","DOIUrl":"10.1016/S1464-1917(01)00059-9","url":null,"abstract":"<div><p>On August 1998 some debris flows were recorded by an automated monitoring system at Acquabona creek (Eastern Italian Alps). In this paper, motion picture of the flow, timing of single coarse particles on the flow surface, geophone recordings and ultrasonic logs were used to obtain velocity, depth and particle size data for the August 17 debris flow. Analogical images, recorded from zenithal camera located along the flow channel axis, have been converted in digital format and then processed in order to obtain a suitable identification of single flowing particles. Through image analysis techniques, grain-size and surface velocity distributions of debris flows are estimated. These properties are of the outmost importance in developing a proper rheological model for debris flows. Front velocities ranged from 1.8 to 4 m/s and corresponding flow surface velocities ranged from 2.26 to 4.18 m/s. A range of slurry shear strengths and viscosities occur in different surges of the same event. These differences in rheological flow behaviour appear to be influenced by concentration of particles and by flow particle-size distributions too. Coarser slurry are related a Bingham flow and finer slurry is associated to Newtonian flow. The development of rigid plugs is an index of rheological behaviour. In the observed surge Bingham flow is characterised by plug widths between 62 and 94% of flow width for flow depth higher than 45 cm. When depth dropped below 45 cm, slurry is finer and more liquid and flow transformed to hyperconcentrated flow. Turbulent small less concentrated surges are caused by a sort of pushing effect of the following coarser debris surge.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 9","pages":"Pages 623-631"},"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)00059-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78873906","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}

引用次数: 25

The E layer shape: the combination with existing models E层形状:与现有模型的结合

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)00006-X

J. Hafner , R. Leitinger , J. Titheridge

引用次数: 0

On volatile particle formation in aircraft exhaust plumes 飞机废气中挥发性微粒的形成

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)00047-2

A. Sorokin, X. Vancassel, P. Mirabel

引用次数: 9

Particle acceleration and wave phenomena in the auroral region 极光区域的粒子加速和波动现象

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(00)00084-2

R.L. Lysak , M. André

引用次数: 1

Radar: Is it a new technology applicable to water level gauging? 雷达:它是一种适用于水位测量的新技术吗?

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)95020-2

S Kranz, T Zenz, U Barjenbruch

引用次数: 9

The shape and evolution of lower hybrid density cavities observed by FREJA 用FREJA观察低杂化密度空腔的形状和演化

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(00)00110-0

S.H. Høymork , H.L. Pécseli , B Lybekk , J. Trusen , A. Eriksson

引用次数: 8

AKR bursts and substorm field line excitation AKR爆发和亚暴场线激发

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(00)00101-X

H. de Feraudy , J. Hanasz , R. Schreiber , G. Parks , M. Brittnacher , S. Perraut , J.A. Sauvaud , F. Lefeuvre , M. Mogilevsky

{"title":"AKR bursts and substorm field line excitation","authors":"H. de Feraudy , J. Hanasz , R. Schreiber , G. Parks , M. Brittnacher , S. Perraut , J.A. Sauvaud , F. Lefeuvre , M. Mogilevsky","doi":"10.1016/S1464-1917(00)00101-X","DOIUrl":"https://doi.org/10.1016/S1464-1917(00)00101-X","url":null,"abstract":"<div><p>A new manifestation of the Auroral Kilometric Radiation is put in evidence through the observations of the POLRAD wave experiment of the INTERBALL mission, the Wide Band Bursts of the AKR, or WBB AKR. It consists in bursts of radiation with a very broad bandwidth, typically 100 – 800 kHz. The whole frequency range is excited at once or in less than few minutes. This corresponds to the excitation of long segments of auroral field lines in a time often less that one minute. The sources of the emission are stretched along the field lines between altitudes ranging from 2000 to 20000 km. The relationship of these bursts to the development of auroral bulges, in the UV spectral range, is shown by the comparison of the POLRAD wave observations and those of the UV imager of the POLAR mission. It is shown that these bursts are generated during fast expansion of the auroral bulge. An accurate timing of the burst events is made with the time evolution of the frequency integrated wave energy flux. It shows that the bursts have a rise time of few minutes which is followed by an exponential relaxation with a characteristic time of few tens of minutes. The source of the bursts first expands along the field lines then it shrinks during the relaxation phase. The bursts are triggered few minutes before the maximum intensity of the UV auroral bulge. It is also shown that the bursts actually consist of a large number of individual broad bandwidth elements, each, lasting less than few seconds.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 151-159"},"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)00101-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91749359","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}

引用次数: 8

Acceleration signatures in the dayside boundary layer and the cusp 日面边界层和尖端的加速度特征

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(00)00107-0

M. Yamauchi , L. Andersson , P.-A. Lindqvist , S. Ohtani , J. Clemmons , J.-E. Wahlund , L. Eliasson , R. Lundin

{"title":"Acceleration signatures in the dayside boundary layer and the cusp","authors":"M. Yamauchi , L. Andersson , P.-A. Lindqvist , S. Ohtani , J. Clemmons , J.-E. Wahlund , L. Eliasson , R. Lundin","doi":"10.1016/S1464-1917(00)00107-0","DOIUrl":"10.1016/S1464-1917(00)00107-0","url":null,"abstract":"<div><p>Freja data show various electron acceleration signatures in the cusp and the dayside boundary layer: (1) time dispersive super-Alfvénic electrons followed by strong wave activity which accompanies transient downward super-thermal electron burst in both the boundary layer and the cusp; (2) quasi-stationary bidirectional electron burst coinciding with localized intense field-aligned current in the boundary layer; (3) downgoing electron burst without visible time dispersion in the cusp; and (4) thermal electrons accelerated by electrostatic potential in both the boundary layer and the cusp. The first and last signatures are different between two regions for typical energies and fluxes, and these differences probably reflect the different auroral emission in the cusp proper (red) and the boundary layer (green). Contributions of these electrons to the large-scale field-aligned currents are also different between two regions. The dispersed electron burst is probably accelerated within 1 Re above the ionosphere. From this result we believe that the cusp red aurora is caused mainly by accelerated electrons, but not by the smoothly entering magnetosheath electrons without acceleration. This also requires revisions of flux transfer event models for the structured cusp red aurora.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 195-200"},"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)00107-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85748201","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}

引用次数: 10

A study of real time ionospheric mapping by neural network 基于神经网络的电离层实时制图研究

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 DOI: 10.1016/S1464-1917(01)00014-9

C. Scotto

引用次数: 7