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NEXRAD ANOMALY: SUNBURST / SUNSPUR
The image shown above is a "sunburst" or a "sun spur." These appear when the
radar is pointed directly at the sun and the sun's radiation hits the receiver
directly.
This will generally happen twice per day: Just after sunrise and just before sunset
when the sun is just above the horizon. Since the sun emits radiation of virtually
all wavelengths the radar is essentially blinded (just as we are) when we look
directly at it.
Sunbursts in the morning will generally be off to the southeast towards the rising
sun and sunbursts in the evening will be off to the southwest towards the setting
sun. The exact angle of the sunburst depends on the location of the NEXRAD site
and the time of year since the sun rises and sets over different points on the horizon
as the seasons progress.
Sunbursts usually will only occur in a single sequential radar image. That is to say,
if you monitor a NEXRAD site or watch a "loop" these anomalies will usually appear in
only a single image. However, some sites have a tendency to exhibit sunbursts over the
course of multiple images. Such sites are usually those that have a clear and
unobstructed view of the horizon--such as on the edge of the ocean or in the middle of
a great expanse of flatlands (the desert, etc.).
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