Correlation studies for B-spline modeled F2 Chapman parameters obtained from FORMOSAT-3/COSMIC data
Summary: The determination of ionospheric key quantities such as the maximum electron density of the F2 layer, the corresponding F2 peak height and the F2 scale height are of high relevance in 4-D ionosphere modeling to provide information on the vertical structure of the electron density distribution. This paper discusses mathematical correlations between these parameters as derived from FORMOSAT-3/COSMIC radio occultations and regionally parameterized by means of polynomial B-splines.
M. Limberger, W. Liang, M. Schmidt, D. Dettmering, M. Hernández-Pajares, and U. Hugentobler Ann. Geophys., 32, 1533-1545, 2014 AbstractFull Article (PDF, 4923 KB)
17 Dec 2014
TID characterised using joint effort of incoherent scatter radar and GPS
M. van de Kamp, D. Pokhotelov, and K. Kauristie Ann. Geophys., 32, 1511-1532, 2014 AbstractFull Article (PDF, 15149 KB)
17 Dec 2014
Energy exchange and wave action conservation for magnetohydrodynamic (MHD) waves in a general, slowly varying medium
Summary: The equation for conservation of wave action is explicitly derived for magnetohydrodynamic waves in a plasma that varies slowly in space and time. Together with generalized ray-tracing equations, it is equivalent to a WKBJ solution of the problem and allows the computation of energy exchange between wave and background plasma as well as the variation of the amplitudes of the field components along the ray. The method is illustrated by application to simple examples.
The numerical simulation on ionospheric perturbations in electric field before large earthquakes
S. F. Zhao, X. M. Zhang, Z. Y. Zhao, and X. H. Shen Ann. Geophys., 32, 1487-1493, 2014 AbstractFull Article (PDF, 353 KB)
09 Dec 2014
On the origin of falling-tone chorus elements in Earth's inner magnetosphere
H. Breuillard, O. Agapitov, A. Artemyev, V. Krasnoselskikh, O. Le Contel, C. M. Cully, V. Angelopoulos, Y. Zaliznyak, and G. Rolland Ann. Geophys., 32, 1477-1485, 2014 AbstractFull Article (PDF, 1201 KB)
08 Dec 2014
A possible influence of the Great White Spot on Saturn kilometric radiation periodicity
Summary: In this paper we show that the large thunderstorm called the "Great White Spot", which raged for about 9 months in Saturn's troposphere in 2010/2011, was accompanied by changes in the periodicity and phasing of auroral radio emissions. We suggest that the thunderstorm was a source of intense gravity waves causing a global change in Saturn’s ionospheric winds via energy and momentum deposition. This supports the theory that Saturn’s magnetospheric periodicities are driven by the upper atmosphere.
G. Fischer, S.-Y. Ye, J. B. Groene, A. P. Ingersoll, K. M. Sayanagi, J. D. Menietti, W. S. Kurth, and D. A. Gurnett Ann. Geophys., 32, 1463-1476, 2014 AbstractFull Article (PDF, 1478 KB)
04 Dec 2014
Correlation of very low and low frequency signal variations at mid-latitudes with magnetic activity and outer-zone particles
A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta
Summary: We discuss three flybys (within an 8-day time span) of comet 1P/Halley by VEGA 1, 2 and Giotto. Looking at two different plasma phenomena: mirror mode waves and field line draping; we study the differences in SW--comet interaction between these three flybys. We find that on this time scale (comparable to Rosetta's orbits) there is a significant difference, both caused by changing outgassing rate of the comet and changes in the solar wind. We discuss implications for Rosetta RPC observations.
M. Volwerk, K.-H. Glassmeier, M. Delva, D. Schmid, C. Koenders, I. Richter, and K. Szegö Ann. Geophys., 32, 1441-1453, 2014 AbstractFull Article (PDF, 3046 KB)
28 Nov 2014
Sporadic E layer at mid-latitudes: average properties and influence of atmospheric tides
A. Pignalberi, M. Pezzopane, and E. Zuccheretti Ann. Geophys., 32, 1427-1440, 2014 AbstractFull Article (PDF, 8568 KB)
21 Nov 2014
Deterministic prediction of surface wind speed variations
Summary: We demonstrate that deterministic forecasting methods can make accurate short-term predictions of wind speed using past data. The predictions are remarkably accurate up to 1 hour and reasonably accurate up to 3 hours. Comparison of the results with f-ARIMA model predictions shows that the deterministic models with suitable parameters are capable of returning improved prediction accuracy and capturing the dynamical variations of the actual time series more faithfully.
G. V. Drisya, D. C. Kiplangat, K. Asokan, and K. Satheesh Kumar Ann. Geophys., 32, 1415-1425, 2014 AbstractFull Article (PDF, 1455 KB)
19 Nov 2014
Nonlocal nonlinear coupling of kinetic sound waves
Summary: Acoustic-type waves are widespread in solar and space plasmas where
they contribute to energy transport and release. We discovered a new
channel for nonlinear coupling among oblique sound waves with vastly
different wavelengths across the background magnetic field. The
resulting nonlocal spectral transfer is much faster than the previously
known transfer produced by the local interactions among waves with