Solar activity variations of meridional winds over King George Island, Antarctica

Arriagada, M.A; Foppiano, A. J.; Buonsanto, M. J.

doi:10.1016/s1364-6826(96)00178-2

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…Although the meridional wind at this midlatitude Asian lo- [Arriagada, 1997], while those at Boulder and Kokubunji have a clear solar cycle dependence for any seasonal condition. The minimum amplitude occurred in 1989, which corresponds to solar maximum, and its value was in the range 34-38 m/s in spring, summer, and autumn but 61 m/s in winter.…”

Section: Seasonal Variationmentioning

confidence: 79%

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂

Igi¹,

Oliver²,

Ogawa³

1999

J. Geophys. Res.

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Abstract. This paper describes an analysis of the meridional equivalent neutral wind for geomagnetically quiet conditions as determined from data collected at the Kokubunji ionosonde station (35.7N, 139.5E), Japan over one solar cycle (1981-1991). The wind is derived from the altitude of peak F 2 layer electron density using the Field Line Interhemispheric Plasma (FLIP) model. For low and moderate solar activity the wind is poleward in the daytime and equatorward in the nighttime. For high solar activity the wind is weak and almost always poleward throughout the day. In winter the local time of peak poleward velocity occurs in the afternoon for low solar activity but in the night for high solar activity. In summer the peak poleward wind occurs in the morning for all levels of solar activity. The diurnal amplitude decreases with increasing solar activity. It also reaches its maximum around the solstices and its minimum around the equinoxes. The mean wind is larger at solar maximum than solar minimum, except for the year 1984. The daily-mean wind is smallest in summer and largest in winter. Qualitatively, the meridional wind at Asian midlatitudes has characteristics similar to those seen in other sectors (such as Millstone Hill, Boulder, Wallops Island, King George Island, and Saint-Santin), but the details in behavior are different and warrant further investigation.

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Section: Seasonal Variationmentioning

confidence: 79%

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂

Igi¹,

Oliver²,

Ogawa³

1999

J. Geophys. Res.

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“…The TEC maps on Figure exhibit significant changes in the TEC level between equinox (March and September) and solstice (June and December) which reveals the seasonal behavior of TEC variation. This well‐known seasonal effect is mainly due to the changes in the pattern of meridional wind circulation (Arriagada et al, ; Karpachev & Gasilov, ; Maruyama et al, ) which in turn is caused by the temperature gradient that makes the whole atmosphere to expand leading to the neutral wind generation. The relative movement of the Earth's axis with respect to the solar ecliptic leads to the displacement of the subsolar point from the tropic of Cancer to the tropic of Capricorn and vice versa.…”

Section: Resultsmentioning

confidence: 99%

Daytime Ionospheric TEC Weather Study Over Latin America

et al. 2018

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The present work is the first of a two‐part weather study of the ionospheric Total Electron Content (TEC), based on data collected by four ground‐based Global Navigation Satellite System networks that cover the whole Latin America from the Patagonia to the north of Mexico. From the best of our knowledge, the maps presented here are the first TEC maps obtained using ground‐based data that covers the entire Latin America region, which represent an advance to the space weather monitoring and forecasting of the ionosphere. This work provides a qualitative and quantitative daytime analysis of the ionospheric TEC variation, which encompasses: (a) the response of TEC to the solar flux at midday; (b) the seasonal variation of TEC in different latitudinal ranges; and (c) the North‐South asymmetry of TEC over Latin America. The response to the solar flux is based on day‐to‐day TEC variations during two periods of different solar activity conditions: 2011 (ascending phase) and 2014 (maximum). The approximations of meridional wind component derived from Horizontal Wind Model‐14 model and hmF2 obtained from International Reference Ionosphere model were used. Equinoctial asymmetries with an opposite configuration in high and moderate solar activity were identified in the TEC variation. For 2011, it was related to the solar flux change. However, in 2014, according to the hmF2 variation, the influence of neutral wind becomes dominant. Among the results, we highlight an absence of winter anomaly in the Northern Hemisphere in 2014 and a stronger annual anomaly for latitudes under −20∘.

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“…The ionosonde winds at Boulder and the ISR winds at Saint Santin show fairly weak trends of the diurnal mean winds with solar activity, while the Millstone Hill ISR winds show a shift from strong southward (equatorward) to near zero or northward (poleward) wind with increasing solar activity [ Hedin et al , 1994, and reference therein]. At King George Island, the mean equivalent winds are more poleward with increasing solar activity [ Arriagada et al , 1997], especially in winter; while at Kokubunji, the trends are just opposite [ Igi et al , 1999]. The contributions of E × B drifts may be one of the factors inducing confusing solar activity trend of the diurnal mean.…”

Section: Discussionmentioning

confidence: 99%

“…Significant differences were found in the solar activity dependences of the diurnal mean and diurnal amplitude of winds from various data sets and models. With increasing solar activity, the diurnal amplitude of the meridional wind was found to decrease at some locations, but the opposite trend was also found in some seasons and at some locations [e.g., Buonsanto , 1991; Duboin and Lafeuille , 1992; Aruliah et al , 1996; Arriagada et al , 1997]. A decrease in the diurnal amplitude was found at some midlatitude stations [ Buonsanto , 1991; Hedin et al , 1994].…”

Section: Introductionmentioning

confidence: 95%

“…In contrast, a higher solar flux results in a larger meridional wind at Kiruna (67.8°N, 20.4°E) of Sweden for each season [ Aruliah et al , 1996]. Furthermore, at a southern midlatitude station, King George Island (62.2°S, 58.8°W), the wind amplitudes decrease from low to high solar activity levels in spring and summer but increase in winter [ Arriagada et al , 1997]. Similarly, the solar cycle variations of the diurnal mean wind are also complicated [e.g., Hedin et al , 1994; Igi et al , 1999; Liu et al , 2003c].…”

Section: Introductionmentioning

confidence: 99%

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Solar activity variations of equivalent winds derived from global ionosonde data

Liu

2004

J. Geophys. Res.

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[1] The equivalent winds at the F layer peak are derived from global ionosonde data to investigate their solar activity variations. With increasing solar activity, the derived equivalent winds are found of nonlinearly decreased diurnal amplitudes in all seasons at most stations. This implies that the increase in ion drag more than compensates for pressure gradients and thus restrains the diurnal amplitude at high solar activity. The diurnal phase of the derived equivalent winds generally shifts later at higher solar activity. It is the first time to explicitly report this striking feature that emerged at so many stations. Another pronounced feature is that the diurnal phase has a summer-winter difference. The diurnal phases at most stations in the Northern Hemisphere are later in winter than in summer at higher solar activity. Furthermore, a decrease in the semidiurnal amplitudes of equivalent winds with increasing solar activity is evident in winter over most stations considered and in other seasons at stations with a lower dip, but the decrease trend becomes weak in other seasons at stations with a larger dip. However, complicated dependences on solar activity can be found in the diurnal mean and the semidiurnal phases of equivalent winds at stations considered.INDEX TERMS: 2427 Ionosphere: Ionosphere/atmosphere interactions (0335); 3369

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Solar activity variations of meridional winds over King George Island, Antarctica

Cited by 8 publications

References 11 publications

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂

Daytime Ionospheric TEC Weather Study Over Latin America

Solar activity variations of equivalent winds derived from global ionosonde data

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Solar activity variations of meridional winds over King George Island, Antarctica

Cited by 8 publications

References 11 publications

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of hmF2

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of hmF2

Daytime Ionospheric TEC Weather Study Over Latin America

Solar activity variations of equivalent winds derived from global ionosonde data

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Product

Resources

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Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂

Solar cycle variations of the thermospheric meridional wind over Japan derived from measurements of h_mF₂