Gravity wave spectra, directions and wave interactions: Global MLT-MFR network
Observations of winds and gravity waves (GW) by MF radars from the Arctic to the Equator are used to provide frequency spectra and spectral variances of horizontal motions, and information on the predominant azimuthal directions of propagation for the waves. The years used are mainly 1993/4; the hei...
Published in: | Earth, Planets and Space |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
TERRA SCIENTIFIC PUBL CO
1999
|
Subjects: | |
Online Access: | http://hdl.handle.net/2440/12492 https://doi.org/10.1186/BF03353214 |
id |
ftunivadelaidedl:oai:digital.library.adelaide.edu.au:2440/12492 |
---|---|
record_format |
openpolar |
spelling |
ftunivadelaidedl:oai:digital.library.adelaide.edu.au:2440/12492 2023-12-17T10:26:41+01:00 Gravity wave spectra, directions and wave interactions: Global MLT-MFR network Manson, A. Meek, C. Hall, C. Hocking, W. MacDougall, J. Franke, S. Igarashi, K. Riggin, D. Fritts, D. Vincent, R. 1999 http://hdl.handle.net/2440/12492 https://doi.org/10.1186/BF03353214 en eng TERRA SCIENTIFIC PUBL CO Earth, Planets and Space, 1999; 51(7-8):543-562 1343-8832 1880-5981 http://hdl.handle.net/2440/12492 doi:10.1186/BF03353214 Vincent, R. [0000-0001-6559-6544] http://dx.doi.org/10.1186/bf03353214 Journal article 1999 ftunivadelaidedl https://doi.org/10.1186/BF0335321410.1186/bf03353214 2023-11-20T23:21:41Z Observations of winds and gravity waves (GW) by MF radars from the Arctic to the Equator are used to provide frequency spectra and spectral variances of horizontal motions, and information on the predominant azimuthal directions of propagation for the waves. The years used are mainly 1993/4; the height layer 76-88 km; and the GW bands 10 100 min. and 1-6 hrs. The high/mid-latitude locations of Tromso, Saskatoon, London/Urbana, Yamagawa, generally demonstrate similar behaviour: the monthly spectra have slopes near -5/3 in winter months, but smaller (absolute) slopes at higher frequencies (<2 hrs.) in summer. Corresponding to this, the spectral densities (10-100 min.) are larger for conditions of higher mean background windspeed--this is related by means of a new correlation-vector technique to GW propagating anti-parallel to the mean zonal winds, and the closure of the solstitial mesospheric jets. Also consistent with this, the sizes and orientations of perturbation ovals (fitted to the wind variations), demonstrate strong semi-annual-oscillations (SAO), and generally similar monthly and latitudinal directions. This suggests strong control, especially of the high-frequency GW band, by the dominant zonal wind-structures of the mesosphere. In contrast the low-latitude locations of Hawaii and Christmas Island demonstrate uniquely different behaviours, with indications of significant inter-annual variability. The frequency spectra for all months tend to have smaller slopes at higher frequencies. Also the dependence of spectral density in both GW bands, upon background wind speed, is negative rather than positive, and is shown to be generally consistent with GW propagating parallel to the mean-global winds. This is consistent with weaker vertical shears in the zonal winds (76-88 km), and lower GW momentum depositions. The perturbation ovals reveal much weaker SAO, and more variable orientations, consistent with more dependency upon GW sources, and less control by the mean winds of the mesosphere. ... Article in Journal/Newspaper Arctic Tromso Tromso The University of Adelaide: Digital Library Arctic Tromso ENVELOPE(16.546,16.546,68.801,68.801) Earth, Planets and Space 51 7-8 543 562 |
institution |
Open Polar |
collection |
The University of Adelaide: Digital Library |
op_collection_id |
ftunivadelaidedl |
language |
English |
description |
Observations of winds and gravity waves (GW) by MF radars from the Arctic to the Equator are used to provide frequency spectra and spectral variances of horizontal motions, and information on the predominant azimuthal directions of propagation for the waves. The years used are mainly 1993/4; the height layer 76-88 km; and the GW bands 10 100 min. and 1-6 hrs. The high/mid-latitude locations of Tromso, Saskatoon, London/Urbana, Yamagawa, generally demonstrate similar behaviour: the monthly spectra have slopes near -5/3 in winter months, but smaller (absolute) slopes at higher frequencies (<2 hrs.) in summer. Corresponding to this, the spectral densities (10-100 min.) are larger for conditions of higher mean background windspeed--this is related by means of a new correlation-vector technique to GW propagating anti-parallel to the mean zonal winds, and the closure of the solstitial mesospheric jets. Also consistent with this, the sizes and orientations of perturbation ovals (fitted to the wind variations), demonstrate strong semi-annual-oscillations (SAO), and generally similar monthly and latitudinal directions. This suggests strong control, especially of the high-frequency GW band, by the dominant zonal wind-structures of the mesosphere. In contrast the low-latitude locations of Hawaii and Christmas Island demonstrate uniquely different behaviours, with indications of significant inter-annual variability. The frequency spectra for all months tend to have smaller slopes at higher frequencies. Also the dependence of spectral density in both GW bands, upon background wind speed, is negative rather than positive, and is shown to be generally consistent with GW propagating parallel to the mean-global winds. This is consistent with weaker vertical shears in the zonal winds (76-88 km), and lower GW momentum depositions. The perturbation ovals reveal much weaker SAO, and more variable orientations, consistent with more dependency upon GW sources, and less control by the mean winds of the mesosphere. ... |
format |
Article in Journal/Newspaper |
author |
Manson, A. Meek, C. Hall, C. Hocking, W. MacDougall, J. Franke, S. Igarashi, K. Riggin, D. Fritts, D. Vincent, R. |
spellingShingle |
Manson, A. Meek, C. Hall, C. Hocking, W. MacDougall, J. Franke, S. Igarashi, K. Riggin, D. Fritts, D. Vincent, R. Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
author_facet |
Manson, A. Meek, C. Hall, C. Hocking, W. MacDougall, J. Franke, S. Igarashi, K. Riggin, D. Fritts, D. Vincent, R. |
author_sort |
Manson, A. |
title |
Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
title_short |
Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
title_full |
Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
title_fullStr |
Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
title_full_unstemmed |
Gravity wave spectra, directions and wave interactions: Global MLT-MFR network |
title_sort |
gravity wave spectra, directions and wave interactions: global mlt-mfr network |
publisher |
TERRA SCIENTIFIC PUBL CO |
publishDate |
1999 |
url |
http://hdl.handle.net/2440/12492 https://doi.org/10.1186/BF03353214 |
long_lat |
ENVELOPE(16.546,16.546,68.801,68.801) |
geographic |
Arctic Tromso |
geographic_facet |
Arctic Tromso |
genre |
Arctic Tromso Tromso |
genre_facet |
Arctic Tromso Tromso |
op_source |
http://dx.doi.org/10.1186/bf03353214 |
op_relation |
Earth, Planets and Space, 1999; 51(7-8):543-562 1343-8832 1880-5981 http://hdl.handle.net/2440/12492 doi:10.1186/BF03353214 Vincent, R. [0000-0001-6559-6544] |
op_doi |
https://doi.org/10.1186/BF0335321410.1186/bf03353214 |
container_title |
Earth, Planets and Space |
container_volume |
51 |
container_issue |
7-8 |
container_start_page |
543 |
op_container_end_page |
562 |
_version_ |
1785578421332475904 |