Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY
<p>Polar mesospheric summer echoes (PMSEs) are very strong radar echoes caused by the presence of ice particles, turbulence, and free electrons in the mesosphere over polar regions. For more than three decades, PMSEs have been used as natural tracers of the complicated atmospheric dynamics of...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2019-02-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/12/955/2019/amt-12-955-2019.pdf |
| _version_ | 1818265424633004032 |
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| author | J. M. Urco J. L. Chau T. Weber R. Latteck |
| author_facet | J. M. Urco J. L. Chau T. Weber R. Latteck |
| author_sort | J. M. Urco |
| collection | DOAJ |
| description | <p>Polar mesospheric summer echoes (PMSEs) are very strong radar echoes
caused by the presence of ice particles, turbulence, and free electrons in
the mesosphere over polar regions. For more than three decades, PMSEs have
been used as natural tracers of the complicated atmospheric dynamics of this
region. Neutral winds and turbulence parameters have been obtained assuming
PMSE horizontal homogeneity on scales of tens of kilometers. Recent radar
imaging studies have shown that PMSEs are not homogeneous on these scales and
instead they are composed of kilometer-scale structures. In this paper, we
present a technique that allows PMSE observations with unprecedented angular
resolution (<span class="inline-formula">∼0.6</span><span class="inline-formula"><sup>∘</sup></span>). The technique combines the concept of
coherent MIMO (Multiple Input Multiple Output) and two high-resolution imaging
techniques, i.e., Capon and maximum entropy (MaxEnt). The resulting
resolution is evaluated by imaging specular meteor echoes. The gain in
angular resolution compared to previous approaches using SIMO (Single Input
Multiple Output) and Capon is at least a factor of 2; i.e., at 85 km, we
obtain a horizontal resolution of <span class="inline-formula">∼900</span> m. The advantage of the new
technique is evaluated with two events of 3-D PMSE structures
showing: (1) horizontal wavelengths of 8–10 km and periods of 4–7 min,
drifting with the background wind, and (2) horizontal wavelengths of
12–16 km and periods of 15–20 min, not drifting with the background wind.
Besides the advantages of the implemented technique, we discuss its current
challenges, like the use of reduced power aperture and processing time, as
well as the future opportunities for improving the understanding of the
complex small-scale atmospheric dynamics behind PMSEs.</p> |
| first_indexed | 2024-12-12T19:50:35Z |
| format | Article |
| id | doaj.art-791e70605d4942f8a19c4d4e226471e5 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-12T19:50:35Z |
| publishDate | 2019-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-791e70605d4942f8a19c4d4e226471e52022-12-22T00:13:59ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482019-02-011295596910.5194/amt-12-955-2019Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSYJ. M. Urco0J. L. Chau1T. Weber2R. Latteck3Leibniz Institute of Atmospheric Physics at the University of Rostock, Rostock, GermanyLeibniz Institute of Atmospheric Physics at the University of Rostock, Rostock, GermanyInstitut für Nachrichtentechnik, University of Rostock, Rostock, GermanyLeibniz Institute of Atmospheric Physics at the University of Rostock, Rostock, Germany<p>Polar mesospheric summer echoes (PMSEs) are very strong radar echoes caused by the presence of ice particles, turbulence, and free electrons in the mesosphere over polar regions. For more than three decades, PMSEs have been used as natural tracers of the complicated atmospheric dynamics of this region. Neutral winds and turbulence parameters have been obtained assuming PMSE horizontal homogeneity on scales of tens of kilometers. Recent radar imaging studies have shown that PMSEs are not homogeneous on these scales and instead they are composed of kilometer-scale structures. In this paper, we present a technique that allows PMSE observations with unprecedented angular resolution (<span class="inline-formula">∼0.6</span><span class="inline-formula"><sup>∘</sup></span>). The technique combines the concept of coherent MIMO (Multiple Input Multiple Output) and two high-resolution imaging techniques, i.e., Capon and maximum entropy (MaxEnt). The resulting resolution is evaluated by imaging specular meteor echoes. The gain in angular resolution compared to previous approaches using SIMO (Single Input Multiple Output) and Capon is at least a factor of 2; i.e., at 85 km, we obtain a horizontal resolution of <span class="inline-formula">∼900</span> m. The advantage of the new technique is evaluated with two events of 3-D PMSE structures showing: (1) horizontal wavelengths of 8–10 km and periods of 4–7 min, drifting with the background wind, and (2) horizontal wavelengths of 12–16 km and periods of 15–20 min, not drifting with the background wind. Besides the advantages of the implemented technique, we discuss its current challenges, like the use of reduced power aperture and processing time, as well as the future opportunities for improving the understanding of the complex small-scale atmospheric dynamics behind PMSEs.</p>https://www.atmos-meas-tech.net/12/955/2019/amt-12-955-2019.pdf |
| spellingShingle | J. M. Urco J. L. Chau T. Weber R. Latteck Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY Atmospheric Measurement Techniques |
| title | Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY |
| title_full | Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY |
| title_fullStr | Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY |
| title_full_unstemmed | Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY |
| title_short | Enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent MIMO and radar imaging at MAARSY |
| title_sort | enhancing the spatiotemporal features of polar mesosphere summer echoes using coherent mimo and radar imaging at maarsy |
| url | https://www.atmos-meas-tech.net/12/955/2019/amt-12-955-2019.pdf |
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