An alternative explanation of PMSE-like scatter in MF radar data
There have been reports in the literature that spaced-antenna MF radars may provide a source of data on Polar Mesospheric Summer Echoes (PMSE). Even though the expected scatter from PMSE at MF frequencies is very much weaker than at VHF, the wide distribution of sites and long duration of data se...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2004-09-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/22/2715/2004/angeo-22-2715-2004.pdf |
| _version_ | 1811253861287985152 |
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| author | G. O. L. Jones M. A. Clilverd P. J. Espy S. Chew D. C. Fritts D. M. Riggin |
| author_facet | G. O. L. Jones M. A. Clilverd P. J. Espy S. Chew D. C. Fritts D. M. Riggin |
| author_sort | G. O. L. Jones |
| collection | DOAJ |
| description | There have been reports in the literature that spaced-antenna MF radars may
provide a source of data on Polar Mesospheric Summer Echoes (PMSE). Even
though the expected scatter from PMSE at MF frequencies is very much weaker
than at VHF, the wide distribution of sites and long duration of data sets
for MF radar systems could provide valuable information about the occurrence
of PMSE. This paper tests whether there is any evidence of PMSE in the
profiles derived using the MF radar at Rothera, Antarctica, one of the few
such radars at high southern latitudes. Over a year of data during 1997/1998
has been analysed for the occurrence of persistent features around midday in
the altitude range 60-95km. Criteria were chosen to test the likelihood
that some of the narrow peaks in the power profiles were manifestations of
electron density structures associated with PMSE. Although a small number of
persistent features were seen at altitudes of 80-85km that are typically
associated with PMSE, there was no seasonality in their occurrence. A
detailed analysis of specific days showed that two peaks were often seen
with altitude separations consistent with the vertical wavelength of the
diurnal tide. Persistent features were also detected at altitudes of 70km
and 90km during the winter months, thus showing a quite different
seasonality to that of PMSE. An estimate of the turbulence caused by the
breaking of gravity waves that have propagated up from the lower atmosphere
shows that at Rothera significant energy is deposited near 80km during
summer, and near 70 and 90km during winter. This seasonal variability is
driven by the screening effect of stratospheric winds, and it appears that
breaking gravity wave dynamics, rather than PMSE phenomena, can explain many
of the localised altitude features in the MF radar data. |
| first_indexed | 2024-04-12T16:57:24Z |
| format | Article |
| id | doaj.art-38b34bbdae6f4a7882c6f5148f0fb2fd |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-04-12T16:57:24Z |
| publishDate | 2004-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-38b34bbdae6f4a7882c6f5148f0fb2fd2022-12-22T03:24:10ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762004-09-01222715272210.5194/angeo-22-2715-2004An alternative explanation of PMSE-like scatter in MF radar dataG. O. L. Jones0M. A. Clilverd1P. J. Espy2S. Chew3D. C. Fritts4D. M. Riggin5British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, U.K.British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, U.K.British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, U.K.British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, U.K.Colorado Research Associates, a division of NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301, USAColorado Research Associates, a division of NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301, USAThere have been reports in the literature that spaced-antenna MF radars may provide a source of data on Polar Mesospheric Summer Echoes (PMSE). Even though the expected scatter from PMSE at MF frequencies is very much weaker than at VHF, the wide distribution of sites and long duration of data sets for MF radar systems could provide valuable information about the occurrence of PMSE. This paper tests whether there is any evidence of PMSE in the profiles derived using the MF radar at Rothera, Antarctica, one of the few such radars at high southern latitudes. Over a year of data during 1997/1998 has been analysed for the occurrence of persistent features around midday in the altitude range 60-95km. Criteria were chosen to test the likelihood that some of the narrow peaks in the power profiles were manifestations of electron density structures associated with PMSE. Although a small number of persistent features were seen at altitudes of 80-85km that are typically associated with PMSE, there was no seasonality in their occurrence. A detailed analysis of specific days showed that two peaks were often seen with altitude separations consistent with the vertical wavelength of the diurnal tide. Persistent features were also detected at altitudes of 70km and 90km during the winter months, thus showing a quite different seasonality to that of PMSE. An estimate of the turbulence caused by the breaking of gravity waves that have propagated up from the lower atmosphere shows that at Rothera significant energy is deposited near 80km during summer, and near 70 and 90km during winter. This seasonal variability is driven by the screening effect of stratospheric winds, and it appears that breaking gravity wave dynamics, rather than PMSE phenomena, can explain many of the localised altitude features in the MF radar data.https://www.ann-geophys.net/22/2715/2004/angeo-22-2715-2004.pdf |
| spellingShingle | G. O. L. Jones M. A. Clilverd P. J. Espy S. Chew D. C. Fritts D. M. Riggin An alternative explanation of PMSE-like scatter in MF radar data Annales Geophysicae |
| title | An alternative explanation of PMSE-like scatter in MF radar data |
| title_full | An alternative explanation of PMSE-like scatter in MF radar data |
| title_fullStr | An alternative explanation of PMSE-like scatter in MF radar data |
| title_full_unstemmed | An alternative explanation of PMSE-like scatter in MF radar data |
| title_short | An alternative explanation of PMSE-like scatter in MF radar data |
| title_sort | alternative explanation of pmse like scatter in mf radar data |
| url | https://www.ann-geophys.net/22/2715/2004/angeo-22-2715-2004.pdf |
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