Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science最新文献_第10页

The effect of the 1999 total solar eclipse on the ionosphere 1999年日全食对电离层的影响

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-06-04 DOI: 10.1016/S1464-1917(01)00016-2

R.A. Bamford

{"title":"The effect of the 1999 total solar eclipse on the ionosphere","authors":"R.A. Bamford","doi":"10.1016/S1464-1917(01)00016-2","DOIUrl":"10.1016/S1464-1917(01)00016-2","url":null,"abstract":"<div><p>The localised “night” created as the moon's shadow travelled across the Earth during the total solar eclipse of 11th August 1999, produced changes in the ionosphere across Europe that were monitored with a variety of modern instrumentation. The passage of the 100km wide, super-sonic lunar shadow offered the opportunity to examine the changes in electron densities, radio absorption, neutral wind patterns and the possible generation of waves in the layers of the ionosphere. All these for an event for which the cause of the disturbance can be calculated with accuracy. Reported here are the results from the vertical ionosondes located under the path of totality and in the partial eclipse region and dual frequency GPS TEC measurements. The ionosondes showed that even in the partial shadow the peak electron densities of the F & E ionospheric layers decreased by as much as 20–35%. The TEC measurements showed that the vertical equivalent line integrated electron density dropped by 15% at the 97% partial eclipse north of the path of totality. The consequences of these observations are discussed in relation to making model predictions.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 5","pages":"Pages 373-377"},"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)00016-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80440822","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: 30

Numerical simulation of secondary planetary waves arising from the nonlinear interaction of the normal atmospheric modes 正常大气模式非线性相互作用产生的次级行星波的数值模拟

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-06-29 DOI: 10.1016/S1464-1917(01)00020-4

A.I. Pogoreltsev

引用次数: 23

Wave energy and momentum fluxes coming to the middle and upper atmosphere from tropospheric mesoscale turbulence 对流层中尺度湍流对中高层大气的波能和动量通量

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-06-29 DOI: 10.1016/S1464-1917(01)00029-0

I.N. Drobyazko, N.M. Gavrilov

引用次数: 2

On the mass dependence of transverse ion acceleration by broad-band extremely low frequency waves 宽带极低频波对横向离子加速的质量依赖性

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-12-06 DOI: 10.1016/S1464-1917(00)00102-1

E.J. Lund , E. Möbius , K.A. Lynch , D.M. Klumpar , W.K. Peterson , R.E. Ergun , C.W. Carlson

引用次数: 11

Variations of the number of weak and strong earthquakes for 1977–1998 years and their possible precursors 1977-1998年强震和弱震次数的变化及其可能的前兆

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2002-02-14 DOI: 10.1016/S1464-1917(01)95028-7

T.V. Barliaeva, M.I. Pudovkin, A.L. Morozova

引用次数: 2

Particle acceleration mechanisms in space plasmas 空间等离子体中的粒子加速机制

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-12-06 DOI: 10.1016/S1464-1917(00)00090-8

M.A. Raadu

{"title":"Particle acceleration mechanisms in space plasmas","authors":"M.A. Raadu","doi":"10.1016/S1464-1917(00)00090-8","DOIUrl":"https://doi.org/10.1016/S1464-1917(00)00090-8","url":null,"abstract":"<div><p>There are many possible mechanisms for particle acceleration in space plasmas. Among these are two broadly defined types that may be characterised on the one hand by large scale electric field structures and on the other hand by stochastic mechanisms and enhanced wave activity. Double layers (DLs) are an example of the first type. They sustain a net potential difference, across which particles are accelerated. Crucial questions concern the generator maintaining the potential, the rate of energy transfer, equilibrium and matching conditions. Magnetic reconnection at an X-type neutral line is another example and shares many characteristics with DLs, such as the cutting of field lines and constraints set by external MHD motions. Particle acceleration by the growth of the modified two- stream instability (MTSI) is an example of the second type. The MTSI is driven by cross magnetic field ion motion and rapidly accelerates electrons. It has been seen as a link in the critical ionisation velocity (CIV) mechanism, which has been extensively studied both in experiments and theory. Crucial questions concern the evolution of the particle energy distribution, the wave source and the saturation of the driving instability.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 55-59"},"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)00090-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91749360","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: 5

Wave-like variations and sudden density decreases in the lower thermosphere as measured by the San Marco V satellite 圣马可5号卫星测量到的低层热层的波状变化和突然的密度下降

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-04-24 DOI: 10.1016/S1464-1917(00)00120-3

E. Illés-Almár , I. Almár , P. Bencze , G. Laneve

{"title":"Wave-like variations and sudden density decreases in the lower thermosphere as measured by the San Marco V satellite","authors":"E. Illés-Almár , I. Almár , P. Bencze , G. Laneve","doi":"10.1016/S1464-1917(00)00120-3","DOIUrl":"10.1016/S1464-1917(00)00120-3","url":null,"abstract":"<div><p>Neutral density measurements were carried out by the microaccelerometer on board the Italian San Marco V satellite in 1988. During the final week of its existence the satellite's perigee decreased to as low as 130 km. Measured density values were compared to the corresponding CIRA '86 (MSIS '86) or to our dMSIS model values. The residuals reveal a wavy structure of different time scales. Characterising the wave amplitude by the average deviation of the residuals, its dependence on different parameters was studied. These investigations demonstrated that the wave-amplitude varies with height, local solar time and geomagnetic disturbance level. There is a particularly developed wave pattern in the average deviations below 200 km. Case studies indicated that there are sudden density decreases of 20–30 sec duration that might be in connection with plasma bubble crossings by the satellite. Altogether 261 such cases were identified and their distribution as a function of height, LST and longitude have been investigated.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 4","pages":"Pages 275-280"},"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)00120-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75312156","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: 4

Auroral potential structures and current-voltage relationship: summary of recent results 极光电位结构和电流-电压关系:近期研究结果综述

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-12-06 DOI: 10.1016/S1464-1917(00)00096-9

P. Janhunen , A. Olsson

{"title":"Auroral potential structures and current-voltage relationship: summary of recent results","authors":"P. Janhunen , A. Olsson","doi":"10.1016/S1464-1917(00)00096-9","DOIUrl":"https://doi.org/10.1016/S1464-1917(00)00096-9","url":null,"abstract":"<div><p>Discrete auroral arcs are caused by precipitating accelerated electrons, and there is a lot of observational evidence for the associated potential structure being U-shaped below about 15000 km altitude. However, according to our studies using Polar data at higher altitude, there is a lack of convergent electric field signatures at ∼20000–35000 km and consequently we suggest that the U-shaped potential contours close below this altitude range. To explain this finding, an O-shaped potential model is proposed, together with a maintenance mechanism which involves parallel energisation of middle-energy electrons by waves in the 15000–30000 km altitude range. Test particle simulations show that the presence of waves brings this “cooperative” model in quantitative agreement with both Polar and low-altitude observations. We also discuss our statistical Freja satellite studies of the observational relationship between the peak energy (voltage) and the current density in inverted-V regions. The result is that the current and voltage are sometimes correlated in the evening sector events, but almost always anticorrelated in the morning sector. This result, which is very interesting in its own right, may also have some relationship to the potential structure question.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 107-111"},"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)00096-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91669910","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: 4

Asymmetric sunlight effect on dayside/nightside auroral precipitation 非对称日照对日侧/夜侧极光降水的影响

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-12-06 DOI: 10.1016/S1464-1917(00)00088-X

C.-I Meng, K. Liou, P.T. Newell

{"title":"Asymmetric sunlight effect on dayside/nightside auroral precipitation","authors":"C.-I Meng, K. Liou, P.T. Newell","doi":"10.1016/S1464-1917(00)00088-X","DOIUrl":"https://doi.org/10.1016/S1464-1917(00)00088-X","url":null,"abstract":"<div><p>There are considerable evidence supporting the novel finding from intensive particle observations that electron acceleration events responsible for producing discrete arcs are more common in darkness than in sunlight [<em>Newell et al.</em>, 1996a]. This sunlight effect on the production of auroral arcs is most dramatic in the pre-midnight sector, and it is still unclear whether the dayside auroras have the same response to the sunlight as the nightside auroras. In this paper we investigate this issue by using auroral images acquired from the ultraviolet imager (UVI) on board the Polar satellite. By analyzing auroral emission in the long Lyman-Birge-Hopfield band (160 – 180 nm), which is approximately proportional to the total energy flux of precipitating electrons over a wide range of auroral electron energies, one can estimate the total energy deposition rate from auroral precipitation. To emphasize the sunlight effect on auroras seasonal averages of auroral luminosities are derived for the winter of 1996 and the summer of 1997 (4 weeks before and after the solstices). It is shown again that auroral intensity in the premidnight sector is suppressed in sunlight. On the contrary, dayside auroral intensity is generally enhanced in sunlight, indicating a different source mechanism for the dayside aurora from the nightside auroras. The suppression of nightside auroras in sunlight is usually attributed to a feedback mechanism, associated with the ionospheric conductivity, when the nightside magnetosphere acts as a current generator. Since precipitating electrons that produce dayside auroras are associated with upward field-aligned currents, the enhancement of dayside auroras in sunlight can be interpreted as a simple circuit system in which the ionosphere is a load and the dayside magnetosphere is a voltage generator.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 1","pages":"Pages 43-47"},"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)00088-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91669913","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: 6

Small satellites for studies in the lower thermosphere 用于低层热层研究的小卫星

Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science Pub Date : 2001-01-01 Epub Date: 2001-04-24 DOI: 10.1016/S1464-1917(00)00119-7

G. Laneve

{"title":"Small satellites for studies in the lower thermosphere","authors":"G. Laneve","doi":"10.1016/S1464-1917(00)00119-7","DOIUrl":"10.1016/S1464-1917(00)00119-7","url":null,"abstract":"<div><p>Among the solutions of the problem of filling the gap in aeronomic data at altitudes ranging from 130 to 200 km an experiment based on the exploitation of a tethered satellite deployed for 100 km or more from the Shuttle, has been proposed. However, this solution seems to be still far away from implementation; whereas other methods based on sounding rocket flights and measurements from the ground present problem like the sporadicness and/or scarce spatial coverage of the observations. As an alternative to these previous approaches this paper studies the possibility of using a satellite on a very eccentric orbit (e ≈ 0.5) as a possible alternative, more rewarding in terms of cost and reliability. In addition to the altitude, the Earth's Thermosphere characteristics depend mainly on the latitude and solar local time. Thus we intend to study the rate of variation of these terms as function of the rate of variations of right ascension of the ascending node and perigee argument, in order to evaluate the time necessary for meeting our requirements in terms of latitudinal and solar local time coverage. Then, the characteristics of a suitable orbit in terms of semi-major-axis and inclination can be determined according to the type of study to be performed. Furthermore we intend to analyze the possible difficulties that could arise when the full separation of any effect is afforded with the aim of selecting the orbit, for a single satellite or for a constellation of small satellites, able to minimize the limitations in the spatial and temporal effects separation.</p></div>","PeriodicalId":101026,"journal":{"name":"Physics and Chemistry of the Earth, Part C: Solar, Terrestrial & Planetary Science","volume":"26 4","pages":"Pages 265-273"},"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)00119-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80230018","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: 0