Influence of solar and geomagnetic activity on sporadic-E layer over low, mid and high latitude stations

To study the influence of solar and geomagnetic activity on Es layers over low, mid and high latitude stations, hourly values of parameters of Es layer during four solar cycles (1970-2010) over different latitude stations are considered. It has been suggested that there is a relationship between solar and geomagnetic activity with Es layer, and the correlations are different over low, mid and high latitude stations. The reasons of different behavior of Es frequency parameters to solar and geomagnetic activity are also studied.