Atmospheric gravity wave production for the solar eclipse of October 23, 1976

Beer, Tom; Goodwin, G.L.; Hobson, G. J.

doi:10.1038/264420a0

Cited by 7 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Comprehensive theoretical treatments of eclipse effects on the middle and upper atmosphere have consistently produced predictions of bow wave generation, but results have also implied that large‐scale waves triggered by shadow passage might be weak and difficult to detect at ionospheric altitudes (Fritts & Luo, ). Studies also predicted that bow waves should only appear at later times during eclipse recovery, when gravity waves generated in the stratosphere were given sufficient time to propagate vertically (Beer et al, ; Eckermann et al, ). Some studies also suggested that waves could be generated directly in the thermosphere (Muller‐Wodarg et al, ).…”

Section: Introductionmentioning

confidence: 99%

Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse

Zhang¹,

Erickson²,

Гончаренко³

et al. 2017

Geophysical Research Letters

120

149

View full text Add to dashboard Cite

During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast-moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere. However, previous geographically limited observations have had difficulty detecting these weak waves within the natural background atmospheric variability, and the existence of eclipse-induced ionospheric waves and their evolution in a complex coupling system remain controversial. During the 21 August 2017 eclipse, high fidelity and wide coverage ionospheric observations provided for the first time an oversampled set of eclipse data, using a dense network of Global Navigation Satellite System receivers at ∼2,000 sites in North America. We show the first unambiguous evidence of ionospheric bow waves as electron content disturbances over central/eastern United States, with ∼1 h duration, 300-400 km wavelength and 280 m/s phase speed emanating from and tailing the totality region. We also identify large ionospheric perturbations moving at the supersonic speed of the maximum solar obscuration which are too fast to be associated with known gravity wave or large-scale traveling ionospheric disturbance processes. This study reveals complex interconnections between the Sun, Moon, and Earth's neutral atmosphere and ionosphere and demonstrates persistent coupling processes between different components of the Earth's atmosphere, a topic of significant community interest. Plain Language Summary During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including the stratosphere and both the thermosphere and ionosphere (∼100-1,000 km altitudes). Theoretical studies since the 1960s have predicted that the Moon's supersonic shadow should generate atmospheric bow waves, similar to a fast-moving river boat. However, observations were geographically limited for these weak and complicated waves. In 2017, high fidelity and wide coverage ionospheric observations were made using a North American Global Navigation Satellite System (GNSS) ∼2,000 receiver network. Eclipse passage generated clear ionospheric bow waves in electron content disturbances emanating from totality primarily over central/eastern United States. Study of wave characteristics reveals complex interconnections between the Sun, Moon, and Earth's neutral atmosphere and ionosphere.

show abstract

Section: Introductionmentioning

confidence: 99%

Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse

Zhang¹,

Erickson²,

Гончаренко³

et al. 2017

Geophysical Research Letters

120

149

View full text Add to dashboard Cite

show abstract

“…A moon shadow of the total solar eclipse travels with high speeds (1,100 m/s to 700 m/s) from the West to East Coast of the continent of United States (CONUS) near the noontime (1000 to 1500 LT) of 21 August 2017. Since 1970, scientists have speculated that a "bow wave" appears around the moon shadow ship (localized heat sink) if the source velocity exceeds the propagation speed of gravity waves (Beer et al, 1976;Beer & May, 1972;Cheng et al, 1992;Chimonas, 1970;Chimonas & Hines, 1970;Davis & da Rosa, 1970;Farges et al, 2003;Hajkowicz, 1977;Hanuise et al, 1982;Hunter et al, 1974;Jakowski et al, 2008;Morton & Essex, 1978;Schodel et al, 1973). The ground-based Global Navigation Satellite System (GNSS) networks in Taiwan and Japan capture the first conclusive evidence of the moon shadow ship-induced bow wave on 22 July 2009 (Liu et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Ionospheric Bow Wave Induced by the Moon Shadow Ship Over the Continent of United States on 21 August 2017

Sun

Liu

Lin

et al. 2018

Geophysical Research Letters

View full text Add to dashboard Cite

A moon shadow of the total solar eclipse swept through the continent of United States (CONUS) from west to east on 21 August 2017. Massive total electron content (integration of electron density from 0 km to 20,200 km altitude) observations from 2,255 ground‐based Global Navigation Satellite System receivers show that the moon shadow ship generates a great ionospheric bow wave front which extends ~1,500 km away from the totality path covering the entire CONUS. The bow wave front consists of the acoustic shock wave due to the supersonic/near‐supersonic moon shadow ship and the significant plasma recombination due to the reduction in solar irradiation within the shadow area. The deep bow wave trough (−0.02 total electron content unit (1 TECU = 1016 el m−2) area) nearly coincides with the 100% obscuration moving along the totality path over the CONUS through the entire eclipse period. The supersonic moon shadow ship induces a bow wave crest in front of the ship (~80% obscuration). It is the first time to find the acoustic shock wave‐formed bow wave trough and crest near the totality.

show abstract

“…Numerous attempts, including model simulations and observations, have been put forward to find the eclipse generated waves in the ionosphere. Although predictions were made by model simulations in early 1970s [Beer and May, 1972;Beer et al, 1976], no obvious signatures and/or conclusive evidences of the eclipse generated bow waves have been observed by means of various groundbased satellite receivers, ionosondes, and Doppler sounders [e.g. Davis and da Rosa, 1970;Schodel et al, 1973, Hunter et al, 1974, Hajkowicz, 1977Morton and Essex, 1978;Hanuise et al, 1982;Cheng et al, 1992;Farges et al, 2003;Jakowski et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

Bow and stern waves triggered by the Moon's shadow boat

Liu¹,

Sun

Kakinami

et al. 2011

Geophys. Res. Lett.

View full text Add to dashboard Cite

It has been predicted that the Moon's shadow, the cooling region, sweeping over the Earth's atmosphere with a supersonic speed could trigger bow waves since 1970. The longest total solar eclipse within next hundred years occurring on 22 July 2009 sweeps over the Eastern Asia region during the noontime period. An analysis of the Hilbert‐Huang transform (HHT) is applied to study ionospheric TEC (total electron content) derived from ground‐based GPS receivers in Taiwan and Japan. We not only find the feature of the predicted bow wave but also the stern wave on the equator side of the eclipse path, as well as the stern wake right behind the Moon's shadow boat. The bow and stern waves are formed by acoustic gravity waves of periods about 3 and/or 5 minutes traveling equatorward with a phase speed of about 100 m/s in the ionosphere.

show abstract

Atmospheric gravity wave production for the solar eclipse of October 23, 1976

Cited by 7 publications

References 9 publications

Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse

Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse

Ionospheric Bow Wave Induced by the Moon Shadow Ship Over the Continent of United States on 21 August 2017

Bow and stern waves triggered by the Moon's shadow boat

Contact Info

Product

Resources

About