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Titel |
Fuzzy logic filtering of radar reflectivity to remove non-meteorological echoes using dual polarization radar moments |
VerfasserIn |
D. R. L. Dufton, C. G. Collier |
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 ; 8, no. 10 ; Nr. 8, no. 10 (2015-10-01), S.3985-4000 |
Datensatznummer |
250116619
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Publikation (Nr.) |
copernicus.org/amt-8-3985-2015.pdf |
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Zusammenfassung |
The ability of a fuzzy logic classifier to dynamically identify
non-meteorological radar echoes is demonstrated using data from the National
Centre for Atmospheric Science dual polarisation, Doppler, X-band mobile
radar. Dynamic filtering of radar echoes is required due to the variable
presence of spurious targets, which can include insects, ground clutter and
background noise. The fuzzy logic classifier described here uses novel
multi-vertex membership functions which allow a range of distributions to be
incorporated into the final decision. These membership functions are derived
using empirical observations, from a subset of the available radar data. The
classifier incorporates a threshold of certainty (25 % of the total
possible membership score) into the final fractional defuzzification to
improve the reliability of the results. It is shown that the addition of
linear texture fields, specifically the texture of the cross-correlation
coefficient, differential phase shift and differential reflectivity, to the
classifier along with standard dual polarisation radar moments enhances the
ability of the fuzzy classifier to identify multiple features. Examples from
the Convective Precipitation Experiment (COPE) show the ability of the filter
to identify insects (18 August 2013) and ground clutter in the presence of
precipitation (17 August 2013). Medium-duration rainfall accumulations across
the whole of the COPE campaign show the benefit of applying the filter prior
to making quantitative precipitation estimates. A second deployment at
a second field site (Burn Airfield, 6 October 2014) shows the applicability
of the method to multiple locations, with small echo features, including
power lines and cooling towers, being successfully identified by the
classifier without modification of the membership functions from the previous
deployment. The fuzzy logic filter described can also be run in near real
time, with a delay of less than 1 min, allowing its use on future field
campaigns. |
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