Studies of medium scale travelling ionospheric disturbances using TIGER SuperDARN radar sea echo observations

He, Long; Dyson, P. L.; Parkinson, M. L.; Wan, Weixing

doi:10.5194/angeo-22-4077-2004

Cited by 31 publications

(56 citation statements)

References 30 publications

(38 reference statements)

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“…Recently, MSTIDs have been studied statistically in many places worldwide using various techniques (Frissell et al 2014(Frissell et al , 2016Fukushima et al 2012;Grocott et al 2013;He et al 2004;Ichihara et al 2013;Ishida et al 2008;Klausner et al 2009;Kotake and Otsuka 2007;Medvedev et al 2013;Oinats et al 2015Oinats et al , 2016Otsuka et al 2011Otsuka et al , 2013Shiokawa et al 2003Shiokawa et al , 2009. In this study, we present observations of MSTIDs' horizontal velocities over Taiwan using HF Doppler sounding.…”

Section: Introductionmentioning

confidence: 91%

Medium-scale traveling ionospheric disturbances over Taiwan observed with HF Doppler sounding

Fišer

Chum

Liu

2017

Earth Planets Space

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We analyzed horizontal velocities of medium-scale traveling ionospheric disturbances using HF Doppler sounding over Taiwan from January 2014 to January 2016. Meridional components of the observed horizontal velocities are in most cases larger than zonal components. In summer, poleward propagation prevails, whereas in winter, disturbances primarily propagate southward. Zonal components of the analyzed events are mostly eastward. Seasonal behaviors of the observed propagation directions are similar at other locations with HF Doppler sounding at middle and low latitudes. Horizontal velocities of the observed events are in the 50-400-ms −1 range. The upper limit is determined using the spacing between reflection points, making the uncertainty in velocity very large for events with velocities larger than this limit. The mean horizontal velocity is 210 ms .

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Section: Introductionmentioning

confidence: 91%

Medium-scale traveling ionospheric disturbances over Taiwan observed with HF Doppler sounding

Fišer

Chum

Liu

2017

Earth Planets Space

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“…Livneh et al (2007) used incoherent scatter radar at Arecibo Observatory to observe quasi-coherent continuous waves with periods of ∼1 h in the ionosphere. These are also typical periods of auroral AGWs (Bristow and Greenwald, 1997) that are likely generated by pulsed ionospheric convection (Prikryl et al, 2005) virtually continuously and sometimes observed as TIDs by SuperDARN He et al, 2004). If auroral medium scale AGWs are observed in the ionosphere above Arecibo they must be ducted through the lower atmosphere waveguide and leak back to thermosphere; otherwise they would be damped and dissipate.…”

Section: Discussionmentioning

confidence: 99%

The influence of solar wind on extratropical cyclones – Part 2: A link mediated by auroral atmospheric gravity waves?

2009

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Abstract. Cases of mesoscale cloud bands in extratropical cyclones are observed a few hours after atmospheric gravity waves (AGWs) are launched from the auroral ionosphere. It is suggested that the solar-wind-generated auroral AGWs contribute to processes that release instabilities and initiate slantwise convection thus leading to cloud bands and growth of extratropical cyclones. Also, if the AGWs are ducted to low latitudes, they could influence the development of tropical cyclones. The gravity-wave-induced vertical lift may modulate the slantwise convection by releasing the moist symmetric instability at near-threshold conditions in the warm frontal zone of extratropical cyclones. Latent heat release associated with the mesoscale slantwise convection has been linked to explosive cyclogenesis and severe weather. The circumstantial and statistical evidence of the solar wind influence on extratropical cyclones is further supported by a statistical analysis of high-level clouds (<440 mb) extracted from the International Satellite Cloud Climatology Project (ISCCP) D1 dataset. A statistically significant response of the high-level cloud area index (HCAI) to fast solar wind from coronal holes is found in mid-tohigh latitudes during autumn-winter and in low latitudes during spring-summer. In the extratropics, this response of the HCAI to solar wind forcing is consistent with the effect on tropospheric vorticity found by Wilcox et al. (1974) and verified by Prikryl et al. (2009). In the tropics, the observed HCAI response, namely a decrease in HCAI at the arrival of solar wind stream followed by an increase a few days later, is similar to that in the northern and southern mid-to-high latitudes. The amplitude of the response nearly doubles for stream interfaces associated with the interplanetary magnetic field B Z component shifting southward. When the IMF B Z after the stream interface shifts northward, the autumn-winter Correspondence to: P. Prikryl (paul.prikryl@crc.ca) effect weakens or shifts to lower (mid) latitudes and no statistically significant response is found at low latitudes in springsummer. The observed effect persists through years of low and high volcanic aerosol loading. The similarity of the response in mid-to-high and low latitudes, the lack of dependence upon aerosol loading, and the enhanced amplitude of the effect when IMF B Z component shifts southward, favor the proposed AGW link over the atmospheric electric circuit (AEC) mechanism (Tinsley et al., 1994). The latter requires the presence of stratospheric aerosols for a significant effect and should produce negative and positive cloud anomalies in mid-to-high and low latitudes, respectively. However, if the requirement of aerosols for the AEC mechanism can be relaxed, the AGW and AEC mechanisms should work in synergy at least in mid-to-high latitudes.

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“…In addition to ground backscatter echoes, there are also echoes backscattered directly by ionospheric irregularities. Separation between the two echo types is performed in the standard way (He et al 2004). …”

Section: Instrumentation and Analysis Methodsmentioning

confidence: 99%

“…A number of papers presenting statistical studies of TIDs have been published in the last 15 years (Afraimovich et al 1999(Afraimovich et al , 2000Ding et al 2008;Kotake et al 2007;Medvedev et al 2013;Otsuka et al 2011;Shiokawa et al 2003;Tsugawa et al 2004). There are also statistical studies that utilized SuperDARN radar data (Bristow et al 1996;He et al 2004;Ichihara et al 2013;Ishida et al 2008;Grocott et al 2013). Apparently, a relatively small number of such studies are related to the complexity of extensive dataset processing, as well as the issues concerning an automated interpretation of HF radar data.…”

Section: Introductionmentioning

confidence: 99%

Statistical study of medium-scale traveling ionospheric disturbances using SuperDARN Hokkaido ground backscatter data for 2011

Oinats

Kurkin

Нишитани

2015

Earth Planets Space

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We describe an automated technique to determine parameters of traveling ionospheric disturbances (TIDs) using the Super Dual Auroral Radar Network (SuperDARN) high frequency (HF) radar data. The technique is based on the analysis of minimum ground backscatter range variations corresponding to different radar beams. Using this technique, we processed the SuperDARN Hokkaido radar data for 2011 and revealed statistical distributions of medium-scale TID (MSTID) azimuth and apparent horizontal velocity. We found four peaks with a distinct diurnal and seasonal dependence in the MSTID azimuth occurrence rate distributions. Northeast MSTID azimuths (20°to 50°) are typical of the summer and equinox morning hours; southeast azimuths (100°to 140°) prevail in the winter daytime; southwest azimuths (190°to 220°) are typical mostly in the summer and equinox nighttime and in the equinox evening; northwest azimuths (280°to 320°) are typical of the summer daytime and evening. The apparent horizontal velocities are generally within the 100 to 160 m/s range. The obtained results agree well with earlier studies by other researchers. However, there are also certain differences. The summer daytime northwestward MSTIDs are not indicated in the earlier studies. The nighttime horizontal velocities are 1.5 to 2 times higher than those in the daytime. Furthermore, winter velocity values are about 1.5 times higher than those in other seasons. These differences might be associated with the peculiarities of the data recorded by different facilities, or the features of the processing techniques, and require further investigation for their interpretation.

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Studies of medium scale travelling ionospheric disturbances using TIGER SuperDARN radar sea echo observations

Cited by 31 publications

References 30 publications

Medium-scale traveling ionospheric disturbances over Taiwan observed with HF Doppler sounding

Medium-scale traveling ionospheric disturbances over Taiwan observed with HF Doppler sounding

The influence of solar wind on extratropical cyclones – Part 2: A link mediated by auroral atmospheric gravity waves?

Statistical study of medium-scale traveling ionospheric disturbances using SuperDARN Hokkaido ground backscatter data for 2011

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