Dr. Brad Muller
The sunrise or
sunset "spike" on the NEXRAD radar occurs when the sun shines directly
into the 1-degree beamwidth of the antenna. Even though the majority of
the sun's radiation comes to us as visible light, the Planck function
tells us that some energy is comes to us at microwave wavelengths,
including specifically the wavelength of NEXRAD. Consider the
following questions on these examples:
(Remember: EST = UTC - 5 hours)
Is this a sunrise or sunset spike? Is this clear air or precipitation mode?
Why does the signal appear stronger farther from the radar?
(Remember: EST = UTC - 5 hours)
Is this a sunrise or sunset spike? Is this clear air or precipitation mode?
Why does the signal appear stronger farther from the radar?
Is this a sunrise or sunset spike? Is this clear air or precipitation mode?
Is this a sunrise or sunset spike? Is this clear air or precipitation mode?
Below left is a sunrise spike at the 0.5 degree elevation angle (N0R). Below right is a sunrise spike at the 1.5 degree elevation angle (N0R). Which occurs later?
