Solar eclipse effects of 22 July 2009 on Sporadic-E

The total solar eclipse of 22 July 2009, was visible from some regions of China and the intense sporadic-E (Es) that broke out during the solar eclipse period over the eastern China provided a unique chance to study solar eclipse effects on the Es-layer. The ground based high-frequency (HF) vertical-incidence and oblique-incidence backscatter radio systems in Wuhan and an HF oblique receivers located in Suzhou were operated to detect the Es-layer. The vertical, oblique and backscatter ionograms of 22 and 23 July were recorded, processed and analyzed. The analyzing results show that the critical frequency of Es, the hop number and power of the rays transmitted from Wuhan to Suzhou as well as the Doppler frequency shift of the one-hop oblique-incidence waves reflected by the Es-layer all increased during the solar eclipse period. These variations are displayed in the paper and explained to be induced by the wind-field, which is produced by the powerful meridional air flows from the sunshine region to the moon's shadow.