Investigation of point echoes

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Investigation of point echoes from GPS-enabled
aircraft to detect anomalous propagation
Scott T. Shipley, ERT and GMU Robert Saffle,
Mitretek Systems Michael H. Jain, NOAA/OAR/NSSL
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WSR-88D point echoes are rejected FMH 11, Part B
Targets capable of independent flight, such as
aircraft and birds that are not tracers of the
wind, provide little useful information to the
meteorologist. The WSR-88D system has the
capability to remove these types of returns from
the data field by logic based on the target radar
cross section and range extent (Point Clutter
Rejection). FMH 11, Part B, Doppler Radar
Theory and Meteorology, FCM-H11B-2005, Appendix
B, Point Targets and Clear Air Returns (page B-3).
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Standard Beam Propagation RE6/5 Occultation by
terrain
?
Radial sample volume at elevation angle e
23rd IIPS, 17 Jan 2007 San Antonio, TX
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23rd IIPS, 17 Jan 2007 San Antonio, TX
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Weather Radar Terrain Occultation Modeling using
GIS Goals of this Presentation
Radar echoes match occultation KEMX point
clutter removed
0044o
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23rd IIPS, 17 Jan 2007 San Antonio, TX
http//www.ncdc.noaa.gov/oa/radar/jnx/index.html.
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Weather Radar Terrain Occultation Modeling using
GIS Goals of this Presentation
Radar echoes match occultation KEMX point
clutter removed
0044o 0149o
5B.8 Radar Apps Page 4b of 11
23rd IIPS, 17 Jan 2007 San Antonio, TX
http//www.ncdc.noaa.gov/oa/radar/jnx/index.html.
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Weather Radar Terrain Occultation Modeling using
GIS Goals of this Presentation
Radar echoes match occultation KEMX point
clutter removed
0044o 0149o 0242o
5B.8 Radar Apps Page 4c of 11
23rd IIPS, 17 Jan 2007 San Antonio, TX
http//www.ncdc.noaa.gov/oa/radar/jnx/index.html.
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Weather Radar Terrain Occultation Modeling using
GIS Goals of this Presentation
Radar echoes match occultation KEMX point
clutter removed
?
?
0044o 0149o 0242o 0338o
B
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23rd IIPS, 17 Jan 2007 San Antonio, TX
http//www.ncdc.noaa.gov/oa/radar/jnx/index.html.
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Level II data KOUN point processing yes
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23rd IIPS, 17 Jan 2007 San Antonio, TX
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Level II data KOUN point processing no
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23rd IIPS, 17 Jan 2007 San Antonio, TX
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Overlay ACARS over KOUN Highlight 2354-2359
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Overlay ACARS over KOUN Highlight 2354-2359
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Theoretical Beam Cross Sections ACARS 2355-2400 ut
B C D
A
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PPI for RDA 6 4.3 degrees no point processing
?Azimuth
Range ?
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PPI for RDA 7 5.25 degrees no point processing
?Azimuth
Range ?
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Investigation of point echoes How rare are the
strikes?
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Investigation of point echoes Finding a needle in
a haystack
Strikes are relatively rare - Aircraft move as
radars scan Two consecutive strikes improves
aircraft certainty - Lower confidence with
isolated ACARS reports Should also seek
confirming Doppler (not tested) - Velocity and
Spectrum Technique would be much more difficult
within rain cells Position uncertainty fairly
large in this study
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Investigation of point echoes Au contraire,
FMH-11, point echoes ARE useful

• Technique could detect/verify AP
• Statistical ensemble might provide info on beam
  structure and variation
• Point Processing would have to be defeated
• Additional feature data generated (OGC)
• ACARS data provision?

?
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