Coherent radar imaging of mesosphere summer echoes: Influence of radar beam pattern and tilted structures on atmospheric echo center

Chen, Jenn-Shyong; Hoffmann, Peter; Zecha, M.; Hsieh, Cheng‐Hsiung

doi:10.1029/2006rs003593

Cited by 18 publications

(19 citation statements)

References 38 publications

(55 reference statements)

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“…The RTI plots indicate most of the well-known features of PMSE, like, e.g., times with a multiple layer structure or the decreasing PMSE intensity between 16:00 to 17:00 UTC, which are common for the Andenes observations. Further, it is possible to see the modulation of the layers within the PMSE due to GW, which is a well-known feature from previous studies (e.g., Rüster et al, 2001;Chilson et al, 2002;Hoffmann et al, 2008;Chen et al, 2008). Based on these observations of the vertical beam we decided to use 83.4 km as the reference height for our wind analysis.…”

Section: Pmse Observations With Maarsymentioning

confidence: 93%

Investigation of gravity waves using horizontally resolved radial velocity measurements

et al. 2013

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Abstract. The Middle Atmosphere Alomar Radar System (MAARSY) on the island of Andøya in Northern Norway (69.3 • N, 16.0 • E) observes polar mesospheric summer echoes (PMSE). These echoes are used as tracers of atmospheric dynamics to investigate the horizontal wind variability at high temporal and spatial resolution. MAARSY has the capability of pulse-to-pulse beam steering allowing for systematic scanning experiments to study the horizontal structure of the backscatterers as well as to measure the radial velocities for each beam direction. Here we present a method to retrieve gravity wave parameters from these horizontally resolved radial wind variations by applying velocity azimuth display and volume velocity processing. Based on the observations a detailed comparison of the two wind analysis techniques is carried out in order to determine the zonal and meridional wind as well as to measure first-order inhomogeneities. Further, we demonstrate the possibility to resolve the horizontal wave properties, e.g., horizontal wavelength, phase velocity and propagation direction. The robustness of the estimated gravity wave parameters is tested by a simple atmospheric model.

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Section: Pmse Observations With Maarsymentioning

confidence: 93%

Investigation of gravity waves using horizontally resolved radial velocity measurements

et al. 2013

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“…6. Although a similar approach was shown by Chilson et al (2002) and Chen et al (2008), our imaging configuration, i.e. longer and higher number of unique baselines than previously used, allows the detection of several patches and we interpret our results as patches and not as aspect sensitivity as Chen et al (2008) had done.…”

Section: Pmse Patch Sizesmentioning

confidence: 83%

“…Although a similar approach was shown by Chilson et al (2002) and Chen et al (2008), our imaging configuration, i.e. longer and higher number of unique baselines than previously used, allows the detection of several patches and we interpret our results as patches and not as aspect sensitivity as Chen et al (2008) had done. Furthermore, we use different beam sizes and integration times given that Sommer et al (2016b) showed that longer integration times lead to a more homogeneously filled beam volume.…”

Section: Pmse Patch Sizesmentioning

confidence: 83%

“…Large aperture radars such as Middle Atmosphere Alomar Radar System (MAARSY) have a strong side lobe suppression of −17 dB (Latteck et al, 2012), but PMSEs can be stronger than that, and hence they can also be detected by side lobes (Chen et al, 2008). On the other hand, wind and turbulence estimation algorithms usually assume that the received signals come from the main beam (Hocking et al, 1986), which is not necessarily the case, especially if PMSEs are not equally distributed in the observation volume and/or they are stronger than the peak-to-side lobe level.…”

Section: Introductionmentioning

confidence: 99%

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Patches of polar mesospheric summer echoes characterized from radar imaging observations with MAARSY

Sommer

Chau

2016

Ann. Geophys.

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Abstract.A recent study has hypothesized that polar mesospheric summer echoes (PMSEs) might consist mainly of localized isotropic scattering. These results have been inferred from indirect measurements. Using radar imaging with the Middle Atmosphere Alomar Radar System (MAARSY), we observed horizontal structures that support our previous findings. We observe that small-scale irregularities, causing isotropic scattering, are organized in patches. We find that patches of PMSEs, as observed by the radar, are usually smaller than 1 km. These patches occur throughout the illuminated volume, supporting that PMSEs are caused by localized isotropic or inhomogeneous scattering. Furthermore, we show that imaging can be used to identify side lobe detections, which have a significant influence even for narrow beam observations. Improved spectra estimations are obtained by selecting the desired volume to study parameters such as spectral width and to estimate the derived energy dissipation rates. In addition, a combined wide beam experiment and radar imaging is used to resolve the radial velocity and spectral width at different volumes within the illuminated volume.

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“…6 for the whole time period, where the panel a shows the echo centers estimated from the original imaging, and the panel b displays the echo centers obtained from the modified imaging. The method for determination of the locations of echo centers is the contour-based approach proposed by Chen et al (2008b).…”

Section: Casementioning

confidence: 99%

Three-dimensional radar imaging of atmospheric layer and turbulence structures using multiple receivers and multiple frequencies

2014

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Abstract. The pulsed, beamwidth-limited atmospheric radar suffers from a finite resolution volume, making it difficult to resolve the small-scale irregularity structure of refractive index (or clear-air turbulence) in the scattering region. Multireceiver and multi-frequency imaging techniques were thus proposed to improve the spatial resolution of the measurements in the finite resolution volume. The middle and upper atmosphere radar (MUR; 34.85 • N, 136.10 • N) possesses the capabilities of 5 frequencies, ranging from 46 MHz to 47 MHz, and up to 25 receivers to carry out the imaging techniques. In this paper, we exhibit the three-dimensional (3-D) radar imaging utilizing five frequencies and 19 receivers of the MUR. The Capon method was employed for the process of imaging, and examinations of a wavy layer and turbulent structures were made, in which the spatial weighting effect on the imaging were mitigated beforehand. Information such as echo center and structure morphology in the resolution volume was then extracted. For example, the location distribution of echo centers could imply the traveling orientation of the wavy layer, which was correspondent with horizontal wind direction. Such information of wavy layer structure was more difficult to disclose without removal of the spatial weighting effect. This paper demonstrates an advanced application of 3-D radar imaging to some practical atmospheric phenomena.

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Coherent radar imaging of mesosphere summer echoes: Influence of radar beam pattern and tilted structures on atmospheric echo center

Cited by 18 publications

References 38 publications

Investigation of gravity waves using horizontally resolved radial velocity measurements

Investigation of gravity waves using horizontally resolved radial velocity measurements

Patches of polar mesospheric summer echoes characterized from radar imaging observations with MAARSY

Three-dimensional radar imaging of atmospheric layer and turbulence structures using multiple receivers and multiple frequencies

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