This is a summary plot of the Hokkaido
radar data for beam 5. There are total
of 16 beam directions: beam 5 is directed
along the line which is about 11 degrees
shifted clockwise from the geographic
The plot consists of 5 panels.
The top panel shows the noise level
versus Universal Time (UT, given
at the bottom). If the level is
above 4, the data might be contaminaed
with other artificial radio waves.
The 2nd panel shows the radar frequency
against UT. The Hokkaido radar is
allowed to use only 5 frequency bands.
These are indicated by the dotted lines.
The 3rd panel shows the amount of
backscatter (color scale, in dB) that
the radar has received at a certain
magnetic latitude (AACGM) on the
ordinate and UT on the abscissa.
The 4th panel shows the Doppler
velocity. Only when and where the
radar has received ionospheric
backscatter, the velocity of
ionospheric plasma and ionospheric
electric field can be determined.
The gray pixels are the so-called
ground (sea) scatter echoes.
They cannot be used for determining
horizontal plasma velocity, but they
can be used to estimate the vertical
motion of the ionosphere. They can
also be used to find Traveling
Ionospheric Disturbances (TIDs).
The bottom panel shows the Doppler
spectral width, that is a measure
of the degree of turbulence of the
ionospheric plasma flow in one pixel.
Ionospheric backscatter echoes have
a larger Doppler spectral width
than ground (sea) scatter echoes.