Modelling ionospheric vertical drifts over Africa low latitudes using Empirical Orthogonal functions and comparison with climatological model

Dubazane, Makhosonke Berthwell; Habarulema, John Bosco; Uwamahoro, Jean

doi:10.1016/j.asr.2017.10.024

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…However, the coefficients of the cubic function should be redetermined for each longitude sector under consideration to take into account local time effects such as contributions to vertical E × B drifts arising from E region migrating and nonmigrating tides and longitudinal conductivity differences (Lühr et al, 2008;Millward et al, 2001). A vital aspect to mention is that our study included the extended low solar activity period of 2008-2010 where low correlation between solar activity and vertical drift has been reported over the African sector (Dubazane et al, 2018). Observations during the extended solar minimum of 2008-2009 showed complex behavior as they disagreed with the previously established understanding that vertical E × B drifts have solar activity dependance (e.g., Fejer et al, 1991;Richmond, 1973) over the equatorial latitudes.…”

Section: Relationship Between C/nofs Vertical Ion Plasma Drift and Ma...mentioning

confidence: 99%

Long‐Term Estimation of Diurnal Vertical E × B Drift Velocities Using C/NOFS and Ground‐Based Magnetometer Observations

et al. 2018

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We report on the development of a new mathematical expression to estimate local daytime (0700–1700 LT) vertical E × B drift in low latitudes using a combination of ground‐based magnetometer measurements and Communications and Navigation Outage Forecasting System (C/NOFS) satellite observations. The expression was developed over Jicamarca (11.8°S, 77.2°W; 0.8°N geomagnetic) and validated with Jicamarca Unattended Long‐Term studies of the Ionosphere and Atmosphere (JULIA) mode and incoherent scatter radar (ISR) measurements during the period 2008–2014. The obtained correlation coefficient (R) values computed using observed and derived vertical E × B drift velocities are 0.79 and 0.84 for ISR and JULIA, respectively when data are available during 2008–2014. Storm‐time comparison between observed and derived vertical E × B drift velocities agreed well with R of 0.92 and 0.87 during 5–8 August 2011 and 8–11 March 2012 geomagnetic storm periods for ISR and JULIA observations, respectively. Overall, we found that the developed expression is applicable in estimating vertical E × B drift response during quiet and geomagnetic storm periods. Based on these findings, we suggest that it is possible to develop accurate daytime global vertical E × B drift model over the equatorial latitude regions using inexpensive magnetometer observations and available satellite data.

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Section: Relationship Between C/nofs Vertical Ion Plasma Drift and Ma...mentioning

confidence: 99%

Long‐Term Estimation of Diurnal Vertical E × B Drift Velocities Using C/NOFS and Ground‐Based Magnetometer Observations

et al. 2018

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“…Although the Fejer-Scherliess drift model was developed for measurements at Jicamarca, we have extended the model to all longitudes since it is used as the vertical ion drift component of the IRI model (Fejer et al, 1999;Bilitza, 2018). However, previous work has compared vertical E Â B drifts in other longitude zones to the drifts in the Fejer-Scherliess drift model and found multiple differences between the vertical drift behavior of the model and observations (e.g., Oyekola & Kolawole, 2010;Saranya et al, 2014;Yizengaw et al, 2014;Dubazane et al, 2018). So although we expect there to be differences between the Fejer-Scherliess model drifts and the C/NOFS drifts, the key finding is the consistency between the C/NOFS drifts and the bubble occurrence frequency.…”

Section: Comparison To Fejer-scherliessmentioning

confidence: 99%

Growin: Modeling ionospheric instability growth rates

Smith

Klenzing²

2022

J. Space Weather Space Clim.

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Seasonal and zonal climatologies of Rayleigh-Taylor growth rates under geomagnetically quiet conditions during solar minimum and solar moderate conditions as a function of local time and altitude are calculated using open source data and software. It is under the action of the Rayleigh-Taylor instability that plumes of depleted plasma, or plasma bubbles, are understood to develop in the bottomside of the equatorial ionosphere. The growin python module utilizes other Heliophysics python modules to collate and process vertical plasma drift to drive the SAMI2 is Another Model of the Ionosphere (SAMI2) model and subsequently calculate the flux tube integrated Rayleigh-Taylor growth rate. The process is repeated for two different types of drift inputs: the Fejer-Scherliess model and measured drifts from the Communication/Navigation Outage Forecasting System (C/NOFS). These growth rates are compared to bubble occurrence frequencies obtained from a dataset of bubbles detected by the C/NOFS satellite. There is agreement between periods of strong positive instability growth and high frequencies of bubble occurrence in both low and moderate solar activity conditions when using C/NOFS drifts. Fejer-Scherliess drifts are only in agreement with bubble occurrence frequencies during moderate solar activity conditions. Bubble occurrence frequencies are often above 25% even when growth rates in the bottomside F region are negative. The climatological nature of the growth rates discussed here begs further study into the day-to-day variability of the growth rate and its drivers.

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“…However the coefficients of the cubic function should be re-determined for each longitude sector under consideration to take into account local time effects such as contributions to vertical E × B drifts arising from E-region migrating and non-migrating tides and longitudinal conductivity differences [Millward et al, 2001;Lühr et al, 2008]. A vital aspect to mention is that our study included the extended low solar activity period of 2008-2010 where low correlation between solar activity and vertical drift has been reported over the African sector [Dubazane et al, 2018]. Observations during the extended solar minimum of 2008-2009 showed complex behaviour as they disagreed with the previously established understanding that vertical E × B drifts have solar activity dependance [e.g., Richmond, 1973;Fejer et al, 1991] over the equatorial latitudes.…”

Section: Relationship Between C/nofs Vertical Ion Plasma Drift and Mamentioning

confidence: 99%

foF2 vs solar indices for the Rome station: Looking for the best general relation which is able to describe the anomalous minimum between cycles 23 and 24

Perna

Pezzopane

2016

Journal of Atmospheric and Solar-Terrestrial Physics

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Modelling ionospheric vertical drifts over Africa low latitudes using Empirical Orthogonal functions and comparison with climatological model

Cited by 9 publications

References 39 publications

Long‐Term Estimation of Diurnal Vertical E × B Drift Velocities Using C/NOFS and Ground‐Based Magnetometer Observations

Long‐Term Estimation of Diurnal Vertical E × B Drift Velocities Using C/NOFS and Ground‐Based Magnetometer Observations

Growin: Modeling ionospheric instability growth rates

foF2 vs solar indices for the Rome station: Looking for the best general relation which is able to describe the anomalous minimum between cycles 23 and 24

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