Ionospheric Map---28th March 2017

Today's early ionospheric map: The important places are those with dense concentration of colour bands.

 The foF2 values used in the mapping process are based on the median of the last 2 hours of station data (4 values per hour). This was done to try to reduce the effect of bad foF2 values. This may mean that the map may lag actual ionospheric behaviour by about an hour, particularly at local dawn periods.
The white line in the map represents the geomagnetic equator. This is where the the magnetic dip is zero. Magnetic dip results from the tendency of a compass needle to align itself vertically with the geomagnetic field, pointing upwards in the northern hemisphere, and downwards in the southern hemisphere. Where the magnetic field is parallel to the Earth's surface, the dip angle is zero and this is referred to as the geomagnetic equator. The geomagnetic field influences the structure of the ionosphere.