Theoretical study of the ionospheric Weddell Sea Anomaly using SAMI2

Chen, C. H.; Huba, J. D.; Saito, Akinori; Lin, Charles; Liu, J. Y.

doi:10.1029/2010ja015573

Cited by 61 publications

(105 citation statements)

References 27 publications

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“…At ionosphere mid-latitudes, the nighttime electron density enhancement has been observed and reported by previous studies (e.g., Bailey et al 1991;Farelo et al 2002;Dabas and Kersley 2003;Luan et al 2008;Park et al 2008;Chen et al 2011Chen et al , 2012Chen et al , 2013Lin et al 2011;Rajesh et al 2016). This density-enhanced ionospheric feature appeared more frequently during solar minimum conditions (Bailey et al 1991), and it is suggested to be caused by larger downward plasma flux from the plasmasphere during the nighttime (Mikhailov et al 2000;Farelo et al 2002;Dabas and Kersley 2003).…”

Section: Introductionsupporting

confidence: 74%

The impact of FORMOSAT-5/AIP observations on the ionospheric space weather

Chen

Lin

Liu

et al. 2017

Terr. Atmos. Ocean. Sci.

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This paper assimilates the in-situ O + fluxes observations obtained from the Advanced Ionospheric Probe (AIP) onboard the upcoming FORMOSAT-5 (FS-5) satellite and evaluates its possible impact on the ionospheric space weather forecast model. The Observing System Simulation Experiment (OSSE), designed for the global O + fluxes, is shown to improve the electron density specification in the vicinity of satellite orbits. The root-mean-square-error (RMSE) of the ionospheric electron density obtained from assimilating the daytime O + fluxes could be improved by ~10 and ~5% for the forecast and nowcast, respectively. Although the improvement of nighttime O + flux assimilation is less significant compared to the daytime assimilation, it still reveals impacts on the model result. This suggests that nighttime observations might not be sufficient to alter the model trajectory in the positive direction as with the daytime result. Alternative data assimilation approaches, such as assimilation of the empirical model built by using the nighttime FS-5/AIP together with other existing satellite observations of O + flux could obtain better accuracy of the electron density forecast.

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Section: Introductionsupporting

confidence: 74%

The impact of FORMOSAT-5/AIP observations on the ionospheric space weather

Chen

Lin

Liu

et al. 2017

Terr. Atmos. Ocean. Sci.

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“…This enhancement is associated primarily with meridional winds and magnetic declination (e.g., [12][13][14]). Figure 3 is a summer case where we can see WSA-like variations for data from both sides.…”

Section: Weddell-sea Anomalymentioning

confidence: 99%

Ionospheric longitudinal variations at midlatitudes: Incoherent scatter radar observation at Millstone Hill

Zhang

Coster

Holt

et al. 2012

Sci. China Technol. Sci.

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Incoherent scatter radar (ISR) extra-wide coverage experiments during the period of 1978-2011 at Millstone Hill are used to investigate longitudinal differences in electron density. This work is motivated by a recent finding of the US east-west coast difference in TEC suggesting a combined effect of changing geomagnetic declination and zonal winds. The current study provides strong supporting evidence of the longitudinal change and the plausible mechanism by examining the climatology of electron density Ne on both east and west sides of the radar with a longitude separation of up to 40 o for different heights within 300-450 km. Main findings include: 1) The east-west difference can be up to 60% and varies over the course of the day, being positive (East side Ne > West side Ne) in the late evening, and negative (West side Ne > East side Ne) in the pre-noon. 2) The east-west difference exists throughout the year. The positive (relative) difference is most pronounced in winter; the negative (relative) difference is most pronounced in early spring and later summer.3) The east-west difference tends to enhance toward decreasing solar activity, however, with some seasonal dependence; the enhancements in the positive and negative differences do not take place simultaneously. 4) Both times of largest positive and largest negative east-west differences in Ne are earlier in summer and later in winter. The two times differ by 12-13 h, which remains constant throughout the year. 5) Variations at different heights from 300-450 km are similar. Zonal wind climatology above Millstone Hill is found to be perfectly consistent with what is expected based on the electron density difference between the east and west sides of the site. The magnetic declination-zonal wind mechanism is true for other longitude sectors as well, and may be used to understand longitudinal variations elsewhere. It may also be used to derive thermospheric zonal winds.

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“…From the first three-dimensional structure of ionospheric WSA, it can be realized that WSA is simpler part of a bigger ionospheric anomaly, namely, the middle latitude summer nighttime anomaly (MSNA) Chen et al 2011Chen et al , 2013. Meanwhile, the MSNA/WSA eastward movement signature have also been comprehensively studied using F3/C observations Liu et al 2015;Chang et al 2015b) and model simulations Sun et al 2015).…”

Section: Formosat-3/cosmicmentioning

confidence: 99%

The fast development of solar terrestrial sciences in Taiwan

et al. 2016

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In Taiwan, research and education of solar terrestrial sciences began with a ground-based ionosonde operated by Ministry of Communications in 1952 and courses of ionospheric physics and space physics offered by National Central University (NCU) in 1959, respectively. Since 1990, to enhance both research and education, the Institute of Space Science at NCU has been setting up and operating ground-based observations of micropulsations, very high-frequency radar, low-latitude ionospheric tomography network, high-frequency Doppler sounder, digital ionosondes, and total electron content (TEC) derived from ground-based GPS receivers to study the morphology of the ionosphere for diurnal, seasonal, geophysical, and solar activity variations, as well as the ionosphere response to solar flares, solar wind, solar eclipses, magnetic storms, earthquakes, tsunami, and so on. Meanwhile, to have better understanding on physics and mechanisms, model simulations for the heliosphere, solar wind, magnetosphere, and ionosphere are also introduced and developed. After the 21 September 1999 Mw7.6 Chi-Chi earthquake, seismo-ionospheric precursors and seismo-traveling ionospheric disturbances induced by earthquakes become the most interesting and challenging research topics of the world. The development of solar terrestrial sciences grows even much faster after National Space Origination has been launching a series of FORMOSAT satellites since 1999. ROCSAT-1 (now renamed FORMO-SAT-1) measures the ion composition, density, temperature, and drift velocity at the 600-km altitude in the low-latitude ionosphere; FORMOSAT-2 is to investigate lightning-induced transient luminous events, polar aurora, and upper atmospheric airglow, and FORMOSAT-3 probes ionospheric electron density profiles of the globe. In the near future, FORMOSAT-5 and FORMOSAT-7/COSMIC-2 will be employed for studying solar terrestrial sciences. These satellite missions play an important role on the recent development of solar terrestrial sciences in Taiwan.

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Theoretical study of the ionospheric Weddell Sea Anomaly using SAMI2

Cited by 61 publications

References 27 publications

The impact of FORMOSAT-5/AIP observations on the ionospheric space weather

The impact of FORMOSAT-5/AIP observations on the ionospheric space weather

Ionospheric longitudinal variations at midlatitudes: Incoherent scatter radar observation at Millstone Hill

The fast development of solar terrestrial sciences in Taiwan

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