Response of the mid-latitude D-region ionosphere to the total solar eclipse of 22 July 2009 studied using VLF signals in South Korean peninsula

•To study the D-region response during July 22 2009 total solar eclipse.•A decrease of ∼6.2dB in VLF signal strength in D-region electron density.•D-region electron density estimated from model shows 95% depletion at 71km.•Results show a change of ∼7km and 0.055km−1 in h′ and β parameters. In this paper, we analyze VLF signals received at Busan to study the the D-region changes linked with the solar eclipse event of 22 July 2009 for very short (∼390km) transmitter–receiver great circle path (TRGCP) during local noon time 00:36–03:13UT (09:36–12:13KST). The eclipse crossed south of Busan with a maximum obscuration of ∼84%. Observations clearly show a reduction of ∼6.2dB in the VLF signal strength at the time of maximum solar obscuration (84% at 01:53UT) as compared to those observed on the control days. Estimated values of change in Wait ionospheric parameters: reflection height (h′) in km and inverse scale height parameter (β) in km−1 from Long Wave Propagation Capability (LWPC) model during the maximum eclipse phase as compared to unperturbed ionosphere are 7km and 0.055km−1, respectively. Moreover, the D-region electron density estimated from model computation shows 95% depletion in electron density at the height of ∼71km. The reflection height is found to increase by ∼7km in the D-region during the eclipse as compared to those on the control days, implying a depletion in the Lyman-α flux by a factor of ∼7. The present observations are discussed in the light of current understanding on the solar eclipse induced D-region dynamics.