Meteor wind observations with the MU radar

Nakamura, Takuji; Tsuda, Toshitaka; Tsutsumi, Masaki; Kita, K.; Uehara, Takafumi; Katō, Susumu; Fukao, S.

doi:10.1029/91rs01164

Cited by 75 publications

(59 citation statements)

References 20 publications

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“…The flexible system design using computer controlled transmitters and receivers, makes it possible to implement various observational setups for special experiments. Meteor echo observation is one of the special setups available in the MU radar (Nakamura et al, 1991), and this has been applied to observing wind velocities and temperature fluctuations (Tsutsumi et al, 1994). The transmission beam pattern is distorted so as to provide maximum radiation at zenith angles of 30-40…”

Section: Mu Radarmentioning

confidence: 99%

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Response of the airglow OH emission, temperature and mesopause wind to the atmospheric wave propagation over Shigaraki, Japan

et al. 2014

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Section: Mu Radarmentioning

confidence: 99%

“…• with an isotropic beam pattern in the azimuth direction, in order to increase the meteor echo number (Nakamura et al, 1991). Reception is handled by an Nakamura et al (1991).…”

Section: Mu Radarmentioning

confidence: 99%

Response of the airglow OH emission, temperature and mesopause wind to the atmospheric wave propagation over Shigaraki, Japan

et al. 2014

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“…In the meteor technique, it is important to select the more short-lived characteristic "underdense" echoes for unambiguous inference of the wind field (Valentic et al, 1997). The meteor radar wind fields presented herein are based on winds derived from individual echoes averaged over 1 h and an estimated area of the order of 150 km×150 km (Nakamura et al, 1991(Nakamura et al, , 1997Hocking et al, 2001). MF radars measure the horizontal movement of plasma irregularities which are assumed to drift at the neutral wind speed spatially averaged over an illuminated area with diameter of the order of 100 km.…”

Section: Datamentioning

confidence: 99%

“…The data originate from meteor radars at Obninsk, (55 • N, 137 • E), Shigaraki (35 • N, 136 • E) and Jakarta (6 • S, 107E) and MF radars using the spaced-antenna method at Hawaii (22 • N, 160 • E;1991-1992, Christmas I. (2 • N, 158 • E) and Adelaide (35 • S, 138 • E).…”

Section: Datamentioning

confidence: 99%

Climatological lower thermosphere winds as seen by ground-based and space-based instruments

Forbes

Portnyagin²,

Skinner³

et al. 2004

Ann. Geophys.

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Abstract. Comparisons are made between climatological dynamic fields obtained from ground-based (GB) and spacebased (SB) instruments with a view towards identifying SB/GB intercalibration issuesE). We focus on monthly-mean prevailing, diurnal and semidiurnal wind components at 96 km, averaged over the 1991-1999 period. We perform space-based (SB) analyses for 90 • longitude sectors including the GB sites, as well as for the zonal mean. Taking the monthly prevailing zonal winds from these stations as a whole, on average, SB zonal winds exceed GB determinations by ∼63%, whereas meridional winds are in much better agreement. The origin of this discrepancy remains unknown, and should receive high priority in initial GB/SB comparisons during the TIMED mission.We perform detailed comparisons between monthly climatologies from Jakarta and the geographically conjugate sites of Shigaraki and Adelaide, including some analyses of interannual variations. SB prevailing, diurnal and semidiurnal tides exceed those measured over Jakarta by factors, on the average, of the order of 2.0, 1.6, 1.3, respectively, for the eastward wind, although much variability exists. For the meridional component, SB/GB ratios for the diurnal and semidiurnal tide are about 1.6 and 1.7. Prevailing and tidal amplitudes at Adelaide are significantly lower than SB valCorrespondence to: J. M. Forbes (forbes@colorado.edu) ues, whereas similar net differences do not occur at the conjugate Northern Hemisphere location of Shigaraki. Adelaide diurnal phases lag SB phases by several hours, but excellent agreement between the two data sources exists for semidiurnal tidal phases throughout the year. These results are consistent with phase retardation effects in the MF radar technique that are thought to exist above about 90 km. Prevailing and tidal amplitudes from Shigaraki track year-to-year variations in SB fields, whereas in the Southern Hemisphere poorer agreement exists. The above hemispheric differences are due in part to MF vs. meteor radar techniques, but zonal asymmetries and day-to-day variability, combined with inadequate sampling, may also be playing a role. Based on these results, some obvious recommendations emerge that are relevant to combined GB/SB studies as part of TIMED and other future aeronomy missions.

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“…Most meteors are observed at ∼90 km (e.g. Nakamura et al, 1991;Hocking et al, 2001). Hourly wind averages are computed for each beam direction giving a lineof-sight wind velocity.…”

Section: The Superdarn and Data Acquisitionmentioning

confidence: 99%

The quasi-two-day wave studied using the Northern Hemisphere SuperDARN HF radars

Malinga

Ruohoniemi

2007

Ann. Geophys.

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Abstract. Data from the Super Dual Radar Network (SuperDARN) radars for 2002 were used to study the behaviour of the quasi-two-day wave (QTDW) in the Northern Hemisphere auroral zone. The period of the QTDW is observed to vary in the range of ∼42-56 h, with the most dominant period being ∼48 h and secondary peaks at ∼42-and ∼52-h. The spectral power shows a seasonal variation with a peak power (max∼70) in summer. The power shows variations of several days and there is also evidence of changes in wave strength with longitude. The 42-h and the 48-h components tend to be strongly correlated in summer. The onset of enhanced wave activity tends to coincide with the westward acceleration of the zonal mean flow and occurs at a time of strong southward meridional flow. The most frequent instantaneous hourly period is in the 40 to 50 h period band, in line with the simultaneous dominance of the 42-h and the 48-h components. The wave numbers are less variable and are around −2 to −4 during times of strong wave activity. For a period of ∼48 h, the zonal wave number is about −3 to −4, using a negative value to indicate westward propagating waves. The 42-h and the 52-h components cover a wider band in the −4 to 1 range. The wide zonal wave number spectrum in our results may account for the observed longitudinal variation in the spectral power of the wave.

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Meteor wind observations with the MU radar

Cited by 75 publications

References 20 publications

Response of the airglow OH emission, temperature and mesopause wind to the atmospheric wave propagation over Shigaraki, Japan

Response of the airglow OH emission, temperature and mesopause wind to the atmospheric wave propagation over Shigaraki, Japan

Climatological lower thermosphere winds as seen by ground-based and space-based instruments

The quasi-two-day wave studied using the Northern Hemisphere SuperDARN HF radars

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