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
north).

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.