HF radar observations of the <i>F</i> region ionospheric plasma response to Storm Sudden Commencements

Kane, Thomas A.; Makarevich, R. A.

doi:10.1029/2009ja014974

Cited by 20 publications

(37 citation statements)

References 55 publications

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“…5e, f). This seems to be inconsistent with the explanation of Kane and Makarevich (2010), but we discovered that within the HAN field of view (FoV), F region electron density is typically larger during pre-noon hours (the density data for the Sodankyla ionosonde, within the HAN FoV, can be found in Ghezelbash, 2013).…”

Section: Discussionmentioning

confidence: 70%

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Variations in the occurrence of SuperDARN F region echoes

2014

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Abstract. The occurrence of F region ionospheric echoes observed by a number of SuperDARN HF radars is analyzed statistically in order to infer solar cycle, seasonal, and diurnal trends. The major focus is on Saskatoon radar data for 1994-2012. The distribution of the echo occurrence rate is presented in terms of month of observation and magnetic local time. Clear repetitive patterns are identified during periods of solar maximum and solar minimum. For years near solar maximum, echoes are most frequent near midnight during winter. For years near solar minimum, echoes occur more frequently near noon during winter, near dusk and dawn during equinoxes and near midnight during summer. Similar features are identified for the Hankasalmi and Prince George radars in the northern hemisphere and the Bruny Island TIGER radar in the southern hemisphere. Echo occurrence for the entire SuperDARN network demonstrates patterns similar to patterns in the echo occurrence for the Saskatoon radar and for other radars considered individually. In terms of the solar cycle, the occurrence rate of nightside echoes is shown to increase by a factor of at least 3 toward solar maximum while occurrence of the near-noon echoes does not significantly change with the exception of a clear depression during the declining phase of the solar cycle.

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Section: Discussionmentioning

confidence: 70%

“…Kane and Makarevich (2010) explained a similar effect for the TIG radar by improved propagation conditions (refraction) during these hours. Similar explanations can be used for the SAS data presented in the current study.…”

Section: Discussionmentioning

confidence: 75%

Variations in the occurrence of SuperDARN F region echoes

2014

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“…Ruohoniemi and Greenwald, 1997;Milan et al, 1997;Ballatore et al, 2000;Parkinson et al, 2003;Koustov et al, 2004;Wild and Grocott, 2008;Kane and Makarevich, 2010;Kumar et al, 2011). These studies have typically focused on a particular subset of effects, which resulted in a number of other effects remaining coupled.…”

Section: T a Kane Et Al: Quiet-time Backscatter Occurrencementioning

confidence: 99%

“…The study by Koustov et al (2004) focused on seasonal dependencies at midnight for all activity levels combined. Also considered were effects of the IMF (Ballatore et al, 2000), magnetospheric substorms (Wild and Grocott, 2008), and geomagnetic storms as defined by storm sudden commencements (Kane and Makarevich, 2010) and temporal filters using Dst time series (Kumar et al, 2011).…”

Section: T a Kane Et Al: Quiet-time Backscatter Occurrencementioning

confidence: 99%

“…In addition, a focus of some recent studies has been on perturbations in the echo occurrence due to elevated geomagnetic activity, which required information on the quiet-time variation to use as a baseline with which to compare and adjust the disturbed backscatter occurrence (Kane and Makarevich, 2010;Kumar et al, 2011). Thus in order to understand the stormtime variations one must understand in detail the quiet-time backscatter occurrence trends, which has not been investigated before.…”

Section: T a Kane Et Al: Quiet-time Backscatter Occurrencementioning

confidence: 99%

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HF radar observations of ionospheric backscatter during geomagnetically quiet periods

2012

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Abstract. The quiet-time coherent backscatter from the Fregion observed by the Tasman International Geospace Environment Radar (TIGER) Bruny Island HF radar is analysed statistically in order to determine typical trends and controlling factors in the ionospheric echo occurrence. A comparison of the F-region peak density values from the IRI-2007 model and ionosonde measurements in the vicinity of the radar's footprint shows a very good agreement, particularly at subauroral and auroral latitudes, and model densities within the radar's footprint are used in the following analyses. The occurrence of F-region backscatter is shown to exhibit distinct diurnal, seasonal and solar cycle variations and these are compared with model trends in the F-region peak electron density and Pedersen conductance of the underlying ionosphere. The solar cycle effects in occurrence are demonstrated to be strong and more complex than a simple proportionality on a year-to-year basis. The diurnal and seasonal effects are strongly coupled to each other, with diurnal trends exhibiting a systematic gradual variation from month to month that can be explained when both electron density and conductance trends are considered. During the night, the echo occurrence is suggested to be controlled directly by the density conditions, with a direct proportionality observed between the occurrence and peak electron density. During the day, the echo occurrence appears to be controlled by both conductance and propagation conditions. It is shown that the range of echo occurrence values is smaller for larger conductances and that the electron density determines what value the echo occurrence takes in that range. These results suggest that the irregularity production rates are significantly reduced by the highly conducting E layer during the day while F-region density effects dominate during the night.

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Investigation of the temperature gradient instability as the source of midlatitude quiet time decameter‐scale ionospheric irregularities: 2. Linear analysis

et al. 2014

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Previous joint measurements by the Millstone Hill incoherent scatter radar and the Super Dual Auroral Radar Network (SuperDARN) HF radar located at Wallops Island, Virginia, have identified the presence of opposed meridional electron density and temperature gradients in the region of decameter‐scale electron density irregularities that have been proposed to be responsible for low‐velocity Sub‐Auroral Ionospheric Scatter observed by SuperDARN radars. The temperature gradient instability (TGI) and the gradient drift instability (GDI) have been extended into the kinetic regime appropriate for SuperDARN radar frequencies and investigated as the causes of these irregularities. A time series for the growth rate of both TGI and GDI has been developed for midlatitude ionospheric irregularities observed by SuperDARN Greenwald et al. (2006). The time series is computed for both perpendicular and meridional density and temperature gradients. This growth rate comparison shows that the TGI is the most likely generation mechanism for the irregularities observed during the experiment and the GDI is expected to play a relatively minor role in irregularity generation.

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HF radar observations of the F region ionospheric plasma response to Storm Sudden Commencements

Cited by 20 publications

References 55 publications

Variations in the occurrence of SuperDARN F region echoes

Variations in the occurrence of SuperDARN F region echoes

HF radar observations of ionospheric backscatter during geomagnetically quiet periods

Investigation of the temperature gradient instability as the source of midlatitude quiet time decameter‐scale ionospheric irregularities: 2. Linear analysis

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