Annales Geophysicae
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Study of sporadic-E clouds by backscatter radar
Annales Geophysicae - Tập 14 - Trang 1060-1065 - 1997
It is shown that swept-frequency backscatter ionograms covering a range of azimuths can be used to study the dynamics of sporadic-E clouds. A simple technique based on analytic ray tracing can be used to simulate the observed narrow traces associated with Es patches. This enables the location and extent of the sporadic-E clouds to be determined. The motion of clouds can then be determined from a t......
Localized structure in the cusp and high-latitude ionosphere: a modelling study
Annales Geophysicae - Tập 17 - Trang 455-462 - 1999
The ionospheric signature of a flux transfer event (FTE) seen in EISCAT radar data has been used as the basis for a modelling study using a new numerical model of the high-latitude ionosphere developed at the University of Sheffield, UK. The evolution of structure in the high-latitude ionosphere is investigated and examined with respect to the current views of polar patch formation and development......
A new airborne polar Nephelometer for the measurements of optical and microphysical cloud properties. Part I: Theoretical design
Annales Geophysicae - Tập 15 - Trang 451-459 - 1997
A new optical sensor, the airborne Polar Nephelometer, is described. The sensor is designed to measure the optical and microphysical parameters of clouds containing either water droplets or ice crystals or a mixture of these particles ranging in size from a few micrometers to about 500 μm diameter. The probe measures the scattering phase function of an ensemble of cloud particles intersecting a co......
Auroral E-region electron density gradients measured with EISCAT
Annales Geophysicae - Tập 18 - Trang 1172-1181 - 2000
In the theory of E-region plasma instabilities, the ambient electric field and electron density gradient are both included in the same dispersion relation as the key parameters that provide the energy for the generation and growth of electrostatic plasma waves. While there exist numerous measurements of ionospheric electric fields, there are very few measurements and limited knowledge about the am......
Properties and origin of energetic particles at the duskside of the Earth’s magnetosheath throughout a great storm
Annales Geophysicae - Tập 17 - Trang 1121-1133 - 1999
We study an interval of 56 h on January 16 to 18, 1995, during which the GEOTAIL spacecraft traversed the duskside magnetosheath from X ≅ −15 to −40 R
E
and the EPIC/ICS and EPIC/STICS sensors sporadically detected tens of energetic particle bursts. This interval coincides with the expansion and growth of a great geomagnetic storm. The flux bursts are strongly de......
Trường điện từ vùng F vào ban đêm tại xích đạo Dịch bởi AI
Annales Geophysicae - Tập 13 - Trang 871-878 - 1995
Sự trôi điện động thẳng đứng của vùng F vào ban đêm tại trạm từ trường xích đạo, Trivandrum được thu thập trong khoảng thời gian 2 năm, 1989 và 1990 (tương ứng với thời kỳ cực đại của chu kỳ mặt trời), sử dụng dữ liệu ionosonde h‘F. Sự dao động theo mùa của sự trôi thẳng đứng được phát hiện có liên quan đến các gradient kinh độ của gió khí quyển nhiệt độ cao. Hơn nữa, sự dao động theo mùa của sự g......
#Trường điện từ #điện động #vùng F #từ trường xích đạo
Jupiter’s Great Red Spot: compactness condition and stability
Annales Geophysicae - Tập 12 - Trang 1-18 - 1994
Linear Rossby wave dispersion relationships suggest that Jupiter’s Great Red Spot (GRS) is a baroclinic structure embedded in a barotropic shearing zonal flow. Quasi-geostrophic (QG) two-layer simulations support the theory, as long as an infinitely deep zonal flow is assumed. However, once a finite depth of the lower layer is assumed, a self-interaction of the baroclinic eddy component produces a......
The study of intermolecular energy transfers in electronic energy quenching for molecular collisions N<sub>2</sub>-N<sub>2</sub>, N<sub>2</sub>-O<sub>2</sub>, O<sub>2</sub>-O<sub>2</sub>Abstract. Contributions of intermolecular electron energy transfers in the electronic quenching are calculated for molecular collisions N2(A3Σu+, W3Δu)+N2(X1Σg+, v=0), N2(A3Σu+)+N2(X1Σg+, v≥0), N2(A3Σu+)+O2(X3Σg−, v=0–2), O2(a1Δg, b1Σg+)+O2(X3Σg−, v=0–2). The calculation has allowed one to estimate the product branching ratios. It is shown that there is a dependence of the calculated rate ... ...
Annales Geophysicae - Tập 26 Số 5 - Trang 1149-1157
Electronic kinetics of molecular nitrogen and molecular oxygen in high-latitude lower thermosphere and mesosphereAbstract. Total quenching rate coefficients of Herzberg states of molecular oxygen and three triplet states of molecular nitrogen in the collisions with O2 and N2 molecules are calculated on the basis of quantum-chemical approximations. The calculated rate coefficients of electronic quenching of O2* and N2* molecules show a good agreement with available experimental data. An influence of c... ...
Annales Geophysicae - Tập 28 Số 1 - Trang 181-192
Meteor fluxes and visual magnitudes from EISCAT radar event rates: a comparison with cross-section based magnitude estimates and optical data
Annales Geophysicae - Tập 16 - Trang 1475-1485 - 1998
Incoherent scatter radars (ISR) are versatile instruments for continuous monitoring of ionisation processes in the Earth’s atmosphere. EISCAT, The European Incoherent Scatter facility has proven effective also in meteor studies. The time resolution of the radar can be reduced to a few milliseconds, sufficient to resolve the passage of individual meteors through the narrow ISR beam. Methods for gro......
Tổng số: 695
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