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Titel |
A method to improve the determination of wave perturbations close to the tropopause by using a digital filter |
VerfasserIn |
P. Alexander, A. Torre, P. Llamedo, R. Hierro, T. Schmidt, A. Haser, J. Wickert |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 9 ; Nr. 4, no. 9 (2011-09-08), S.1777-1784 |
Datensatznummer |
250002089
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Publikation (Nr.) |
copernicus.org/amt-4-1777-2011.pdf |
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Zusammenfassung |
GPS radio occultation satellite data allowed to analyze in the last
decade for the first time a large amount of atmospheric temperature
profiles including both the troposphere and the stratosphere all
over the globe. Wave amplitude enhancements have been systematically
observed around tropopause levels, which are apparently due to
artifacts generated by any digital filter used to isolate the wave
components from these data. We present a new filtering method which
can be equally applied to temperature or refractivity profiles. It
was tested with synthetic temperature data based on NCEP reanalyes
and observed wave climatologies and it was
also statistically validated with GPS radio occultation profiles
from the COSMIC mission. The suggested technique significantly
reduces artificial enhancements around the tropopause, mainly at low
latitudes, where a sharp lapse rate change usually exists. This
represents an improvement in comparison to previous applications of
standard filters. In addition it would allow the study of longer
vertical wavelengths than previously done with other filtering
procedures. |
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