نتایج جستجو برای: equatorial ionosphere

تعداد نتایج: 16712  

2009
AZAMI ZAHARIM

GPS receivers have been profitably employed by researchers for investigations into ionospheric and atmospheric science. However, a number of improvements in measurement accuracy are necessary for today’s applications. The ionosphere has practical importance in GPS applications because it influences transionospheric radio wave propagation. Total Electron Content (TEC) is one of the parameters of...

2004
T. W. Garner

At the Low-Frequency Array (LOFAR)(Planet. Space Sci. (2004) these proceedings) frequencies (HF/VHF), extraterrestrial radiation experiences substantial propagation delay as it passes through the ionosphere. The adaptive calibration technique to be employed by LOFAR will use signals from many known bright radio sources in the sky to estimate and remove the effects of this delay. This technique ...

2006
Luke Moore Andrew F. Nagy Arvydas J. Kliore Ingo Müller-Wodarg John D. Richardson Michael Mendillo

[1] Recent radio occultations of Saturn’s equatorial ionosphere by the Cassini spacecraft provide important insight into this poorly constrained region. Twelve new electron density profiles identify a clear dawn/dusk asymmetry as well as two apparently separate electron density peaks. This study uses a 3D general circulation model along with 1D water diffusion calculations to examine the possib...

Journal: :Earth, Planets and Space 2022

Abstract The ionosphere exhibits some characteristic perturbations during sudden stratospheric warming (SSW) events, of which the mechanism is not thoroughly understood. This study focuses on latitudinal and interhemispheric differences enhanced semi-diurnal lunitidal (M2) related to SSW using total electron content calculated from network Global Navigation Satellite System ionosonde data in ea...

2004
Yurii V. Dumin

An accuracy of the last version of International Reference Ionosphere IRI-2001 at low latitudes is tested by a detailed comparison of longitudinal variations in the equatorial anomaly development following from this model with the ones given by independent ISS-b satellite data. A few drawbacks of IRI-2001 were revealed, particularly, (1) its longitudinal variations are substantially oversmoothe...

2017
Bela G. Fejer M. C. Kelley C. A. Gonzales

Anomalous reversals of the zonal equatorial electric field component have sometimes been observed when the interplanetary magnetic field turns northward from a steady southerly direction. We suggest that this reversal is associated with a sudden change in the convection electric field in the magnetosphere and present measurements to support this explanation. Although slower variations in the co...

2005
Yurii V. Dumin

An accuracy of the last version of International Reference Ionosphere IRI-2001 at low latitudes is tested by a detailed comparison of longitudinal variations in the equatorial anomaly development following from this model with the ones given by independent ISS-b satellite data. A few drawbacks of IRI-2001 were revealed, particularly, (1) its longitudinal variations are substantially oversmoothe...

2011
D. Snowden R. Winglee C. Bertucci M. Dougherty

[1] Using a three-dimensional multifluid simulation, we demonstrate the importance of ion gyroradius and heavy ion effects when characterizing Titan’s plasma interaction with the Kronian magnetosphere. Ion gyroradius and heavy ion effects drastically change the mass loading and magnetic field draping at Titan. We find that the large ion gyroradius of picked up ionospheric species results in an ...

Journal: :Annales Geophysicae 2022

Abstract. This work uses the Disturbance Ionosphere indeX (DIX) to evaluate ionospheric responses equatorial plasma bubble (EPB) events from 2013 2020 over Brazilian and low latitudes. We have compared DIX variations during EPBs ionosonde All-Sky Imager data, aiming physical characteristics of these events. Our results show that was able detect EPB-related TEC disturbances in terms their intens...

2005
Michael Mendillo Luke Moore John Clarke Ingo Mueller-Wodarg William S. Kurth M. L. Kaiser

[1] A long-standing discrepancy exists in determinations from observations and modeling of the diurnal variation of the peak electron density of Saturn’s ionosphere. Using a new Saturn-Thermosphere-Ionosphere-Model (STIM), we examine the suggestion by Burns et al. (1983) that Saturn’s rings shadow its ionosphere causing radio penetration ‘‘holes’’, thereby allowing lightning-induced radio signa...

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