THE MORPHOLOGY AND OCCURRENCE OF E_s-s OVER WUCHANG,CHINA

The occurrence and morphology of ionospheric E_s-s over Wuchang,China,are examined and statistically analysed.The E_s-s over this area is possessed of high occurrence and clear trace.We consider that E_s-s is neither an intrinsic companion of magnetic disturbances,nor a phenomenon existing exclusively in the auroral zones and in the geomagnetic equatorial region. Over this area,E_s-s occurred mostly in magnetic quiet days,and the maximum of occurrence rate is arround 09^h or 10^h LMT diurnally and in summer months seasonally.No effect on this feature due to variations of geomagnetic field or solar activity has so far been detected.