Sporadic E critical frequency, foEs

It is apparent from the graph of sporadic E vs time, that the KEL at Slough sees far more Es layers than the D.P.S. at Chilton (around 90 percent compared with approximately 40 percent at Chilton). Es layers are recorded by both sounders between 15 and 36 percent of the time each month. When this data is compared, it becomes apparent that the D.P.S at Chilton sees denser Es layers than Slough on a considerable number of occasions. Es layers are known to be a localised phenomenon, but this does not account for the difference in the number of observations at each site, or the fact that the Chilton sounder regularly records a greater foEs than Slough. Since it is unlikely that the occurrence of sporadic-E layers is very different on average between two sounders separated by 50 km, the difference in statistics is probably due to a difference in the sensitivity of the two instruments.


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11/08/97 Chris Davis