Meteor radar wind over Chung-Li (24.9°N, 121°E), Taiwan, for the period 10-25 November 2012 which includes Leonid meteor shower: Comparison with empirical model and satellite measurements

Su, Ching Lun; Chen, H. C.; Chu, Yen Hsyang; Chung, Ming-Chao; Kuong, Ruey Ming; Lin, Tang-Huang; Tzeng, K. J.; Wang, C. Y.; Wu, Kuo Hui; Yang, Kai

doi:10.1002/2013rs005273

Cited by 12 publications

(9 citation statements)

References 64 publications

(76 reference statements)

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“…For example, gravity wave measurements using airglow instruments, lidars, and riometers can only be made up to about 90 km (Ehard et al, ; Jarvis et al, ; Shiokawa et al, ; Smith et al, ). Meteor radars can measure at around 100 km altitude (Su et al, ), but there are a limited number of such instruments at the dune latitudes. In general, gravity waves are not to our knowledge measured through auroral emission.…”

Section: Interpretation and Conclusionmentioning

confidence: 99%

Citizen Scientists Discover a New Auroral Form: Dunes Provide Insight Into the Upper Atmosphere

Palmroth

Grandin

Helin³

et al. 2020

AGU Advances

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Auroral forms are like fingerprints linking optical features to physical phenomena in the near-Earth space. While discovering new forms is rare, recently, scientists reported of citizens' observations of STEVE, a pinkish optical manifestation of subauroral ionospheric drifts that were not thought to be visible to the naked eye. Here, we present a new auroral form named "the dunes". On 7 October 2018, citizen observers took multiple digital photographs of the same dunes simultaneously from different locations in Finland and Sweden. We develop a triangulation method to analyze the photographs and conclude that the dunes are a monochromatic wave field with a wavelength of about 45 km within a thin layer at 100 km altitude. Supporting data suggest that the dunes manifest atmospheric waves, possibly mesospheric bores, which are rarely detected, and have not previously been observed via diffuse aurora nor at auroral latitudes and altitudes. The dunes present a new opportunity to investigate the coupling of the lower/middle atmosphere to the thermosphere and ionosphere. Our paper adds to the growing body of work that illustrates the value of citizen scientist images in carrying out quantitative analysis of optical phenomena, especially at small scales at subauroral latitudes. Further, the dune project presents means to create general interest toward physics, emphasizing that citizens can take part in scientific work by helping to uncover new phenomena. Plain Language SummaryAbove Earth's atmosphere at about 80-120 km altitude, lies a region that is often dubbed as the "ignorosphere," one of the least explored regions at our planet. We present a new auroral form spotted by citizen scientists and show how it can be used to investigate the ignorosphere. We name the new form as "the dunes" and develop a method to analyze the citizen scientist pictures using the stars on the skies as reference points. The new method and other supporting data indicate that the dunes are a monochromatic wave field with a wavelength of about 45 km within a thin layer at 100 km altitude, right in the ignorosphere, where atmosphere meets the electromagnetic forcing from space. The analysis suggests that the dunes manifest atmospheric waves, possibly a rare phenomenon called mesospheric bores, which are large wave fields propagating in the ignorosphere. They have not previously been observed via aurora, nor at auroral latitudes and altitudes. The dunes present a new opportunity to investigate the ignorosphere and its driving from above. Further, the dune project presents means to create general interest toward physics, emphasizing that citizens can take part in scientific work by helping to uncover new phenomena. Key Points: • Citizen scientists discover a new auroral form, named the dunes, presenting a large-scale monochromatic wave field • We develop a triangulation method using citizen scientist photographs as science data • We suggest that the dunes manifest mesospheric bores, which have not previously been observed in the diffuse aurora Suppo...

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Section: Interpretation and Conclusionmentioning

confidence: 99%

Citizen Scientists Discover a New Auroral Form: Dunes Provide Insight Into the Upper Atmosphere

Palmroth

Grandin

Helin³

et al. 2020

AGU Advances

View full text Add to dashboard Cite

show abstract

“…For example, gravity wave measurements using airglow instruments, lidars, and riometers can only be made up to about 90 km (Ehard et al, 2014;Jarvis et al, 2003;Shiokawa et al, 1999;Smith et al, 2000). Meteor radars can measure at around 100 km altitude (Su et al, 2014), but there are a limited number of such instruments at the dune latitudes. In general, gravity waves are not to our knowledge measured through auroral emission.…”

Section: Agu Advancesmentioning

confidence: 99%

Citizen scientists discover a new auroral form: Dunes provide insight into the upper atmosphere

Palmroth

Grandin

Helin³

et al. 2020

Preprint

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<p>Auroral forms are like fingerprints linking optical features to physical phenomena in the near-Earth space. While discovering new forms is rare, recently scientists reported of citizens' observations of STEVE, a pinkish optical manifestation of subauroral ionospheric drifts that were not thought to be visible to the naked eye. Here, we present a new auroral form named "the dunes". On Oct 7, 2018, citizen observers took multiple digital photographs of the same dunes simultaneously from different locations in Finland and Sweden. We develop a triangulation method to analyse the photographs, and conclude that the dunes are a monochromatic wave field with a wavelength of about 45 km within a thin layer at 100 km altitude. Supporting data suggest that the dunes manifest atmospheric waves, possibly mesospheric bores, which are rarely detected, and have not previously been observed via diffuse aurora, nor at auroral latitudes and altitudes. The dunes present a new opportunity to investigate the coupling of the lower/middle atmosphere to the thermosphere and ionosphere. We conclude that the the dunes may provide new insights into the structure of the mesopause as a response to driving by ionospheric energy deposition via Joule heating and electron precipitation.&#160;Further, our paper adds to the growing body of work that illustrates the value of citizen scientist images in carrying out quantitative analysis of optical phenomena, especially at small scales at subauroral latitudes. The dune project presents means to create general interest towards physics, emphasising that citizens can take part in scientific work by helping to uncover new phenomena.</p>

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“…The Chung-Li VHF radar system, operated at a central frequency of 52 MHz, has been upgraded for several years and carried out some valuable studies for the atmosphere (Chu et al, 2013;Su et al, 2014). In addition to a great improvement in radar signal processing, various pulse shapes such as rectangular, Gaussian, and trapezoid are available, and typical pulse widths are 1, 2, and 4 µs, yielding range gate resolutions of 150, 300, and 600 m, respectively.…”

Section: Range Imaging Technique Of the Chung-li Vhf Radarmentioning

confidence: 99%

Evaluation of multifrequency range imaging technique implemented on the Chung–Li VHF atmospheric radar

Chen

Tsai

et al. 2016

Atmos. Meas. Tech.

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Abstract. The multifrequency range imaging technique (RIM) has been implemented on the Chung-Li VHF array radar since 2008 after its renovation. This study made a more complete examination and evaluation of the RIM technique to facilitate the performance of the radar for atmospheric studies. RIM experiments with various radar parameters such as pulse length, pulse shape, receiver bandwidth, transmitter frequency set, and so on were conducted. The radar data employed for the study were collected from 2008 to 2013. It has been shown that two factors, the range/time delay of the signal traveling in the media and the standard deviation of Gaussian-shaped range-weighting function, play crucial roles in ameliorating the RIM-produced brightness (or power distribution); the two factors are associated with some radar parameters and system characteristics. The range/time delay of the signal was found to increase with time; moreover, it was slightly different for the echoes from the atmosphere with and without the presence of significant precipitation. A procedure of point-by-point correction of range/time delay was thus executed for the presence of precipitation to minimize the bogus brightness discontinuity at range gate boundaries. With the RIM technique, the Chung-Li VHF radar demonstrates its first successful observation of double-layer structures as well as their temporal and spatial variations with time.

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Meteor radar wind over Chung-Li (24.9°N, 121°E), Taiwan, for the period 10-25 November 2012 which includes Leonid meteor shower: Comparison with empirical model and satellite measurements

Cited by 12 publications

References 64 publications

Citizen Scientists Discover a New Auroral Form: Dunes Provide Insight Into the Upper Atmosphere

Citizen Scientists Discover a New Auroral Form: Dunes Provide Insight Into the Upper Atmosphere

Citizen scientists discover a new auroral form: Dunes provide insight into the upper atmosphere

Evaluation of multifrequency range imaging technique implemented on the Chung–Li VHF atmospheric radar

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