Coherent MIMO to Improve Aperture Synthesis Radar Imaging of Field-Aligned Irregularities: First Results at Jicamarca

Urco, Juan Miguel; Chau, Jorge L.; Milla, Marco; Vierinen, Juha; Weber, Tobias

doi:10.1109/tgrs.2017.2788425

Cited by 39 publications

(50 citation statements)

References 53 publications

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“…This unique observation has been made with the Middle Atmosphere Alomar Radar System (MAARSY) located in northern Norway. The clear quantification is possible due to an improved radar imaging of Polar Mesospheric Summer echoes (PMSEs) that utilizes a Multiple‐Input Multiple‐output (MIMO) approach developed by Urco et al (). Currently there is general consensus that PMSEs are generated by atmospheric turbulence, but require the presence of free electrons and charged iced particles (e.g., Varney et al, and references therein) to increase the signal‐to‐noise ratio of the echoes sufficiently to make them observable with relatively low power atmospheric radars.…”

Section: Introductionmentioning

confidence: 99%

Four‐Dimensional Quantification of Kelvin‐Helmholtz Instabilities in the Polar Summer Mesosphere Using Volumetric Radar Imaging

Chau

Urco

Avsarkisov

et al. 2020

Geophysical Research Letters

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We present and characterize in time and three spatial dimensions a Kelvin‐Helmholtz Instability (KHI) event from polar mesospheric summer echoes (PMSE) observed with the Middle Atmosphere Alomar Radar System. We use a newly developed radar imaging mode, which observed PMSE intensity and line of sight velocity with high temporal and angular resolution. The identified KHI event occurs in a narrow layer of 2.4 km thickness centered at 85 km altitude, is elongated along north‐south direction, presents separation between billows of ∼8 km in the east‐west direction, and its billow width is ∼3 km. The accompanying vertical gradients of the horizontal wind are between 35 and 45 m/s/km and vertical velocities inside the billows are ±12 m/s. Based on the estimated Richardson ( <0.25), horizontal Froude ( ∼0.8), and buoyancy Reynolds ( ∼2.5 × 10 4 ) numbers, the observed event is a KHI that occurs under weak stratification and generates strong turbulence.

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Section: Introductionmentioning

confidence: 99%

Four‐Dimensional Quantification of Kelvin‐Helmholtz Instabilities in the Polar Summer Mesosphere Using Volumetric Radar Imaging

Chau

Urco

Avsarkisov

et al. 2020

Geophysical Research Letters

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“…Geometry of a projected velocity of neutral wind, measured using a specular meteor trail echo observed with a bistatic radar, where ⃗ k i , ⃗ k s , and ⃗ k are the incident, scattered, and Bragg wavectors, respectively. Hysell et al, 2016;Urco, Chau, Milla, et al 2018;Vierinen et al, 2016).…”

Section: 1029/2019ea000570mentioning

confidence: 99%

Observing Mesospheric Turbulence With Specular Meteor Radars: A Novel Method for Estimating Second‐Order Statistics of Wind Velocity

Vierinen

Chau

Charuvil

et al. 2019

Earth and Space Science

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There are few observational techniques for measuring the distribution of kinetic energy within the mesosphere with a wide range of spatial and temporal scales. This study describes a method for estimating the three‐dimensional mesospheric wind field correlation function from specular meteor trail echoes. Each radar echo provides a measurement of a one‐dimensional projection of the wind velocity vector at a randomly sampled point in space and time. The method relies on using pairs of such measurements to estimate the correlation function of the wind with different spatial and temporal lags. The method is demonstrated using a multistatic meteor radar data set that includes ≈105 meteor echoes observed during a 24‐hr time period. The new method is found to be in good agreement with the well‐established technique for estimating horizontal mean winds. High‐resolution correlation functions with temporal, horizontal, and vertical lags are also estimated from the data. The temporal correlation function is used to retrieve the kinetic energy spectrum, which includes the semidiurnal mode and a 3‐hr period wave. The horizontal and vertical correlation functions of the wind are then used to derive second‐order structure functions, which are found to be compatible with the Kolmogorov prediction for spectral distribution of kinetic energy in the turbulent inertial range. The presented method can be used to extend the capabilities of specular meteor radars. It is relatively flexible and has a multitude of applications beyond what has been shown in this study.

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“…• Implementation of coherent MIMO configurations using code diversity (Urco et al, 2018a). Coherent MIMO can be used to take advantage of the spatial information arising from distributed transmitter modules.…”

Section: 1029/2018rs006688mentioning

confidence: 99%

The Case for Combining a Large Low‐Band Very High Frequency Transmitter With Multiple Receiving Arrays for Geospace Research: A Geospace Radar

et al. 2019

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We argue that combining a high‐power, large‐aperture radar transmitter with several large‐aperture receiving arrays to make a geospace radar—a radar capable of probing near‐Earth space from the upper troposphere through to the solar corona—would transform geospace research. We review the emergence of incoherent scatter radar in the 1960s as an agent that unified early, pioneering research in geospace in a common theoretical, experimental, and instrumental framework, and we suggest that a geospace radar would have a similar effect on future developments in space weather research. We then discuss recent developments in radio‐array technology that could be exploited in the development of a geospace radar with new or substantially improved capabilities compared to the radars in use presently. A number of applications for a geospace radar with the new and improved capabilities are reviewed including studies of meteor echoes, mesospheric and stratospheric turbulence, ionospheric flows, plasmaspheric and ionospheric irregularities, and reflection from the solar corona and coronal mass ejections. We conclude with a summary of technical requirements.

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Coherent MIMO to Improve Aperture Synthesis Radar Imaging of Field-Aligned Irregularities: First Results at Jicamarca

Cited by 39 publications

References 53 publications

Four‐Dimensional Quantification of Kelvin‐Helmholtz Instabilities in the Polar Summer Mesosphere Using Volumetric Radar Imaging

Four‐Dimensional Quantification of Kelvin‐Helmholtz Instabilities in the Polar Summer Mesosphere Using Volumetric Radar Imaging

Observing Mesospheric Turbulence With Specular Meteor Radars: A Novel Method for Estimating Second‐Order Statistics of Wind Velocity

The Case for Combining a Large Low‐Band Very High Frequency Transmitter With Multiple Receiving Arrays for Geospace Research: A Geospace Radar

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