spase://ASWS/NumericalData/Ionogram/Cch_Ionogram

Ionograms are an image of frequency versus time delay (virtual height) of HF echoes from the ionosphere recorded by an ionosonde. An ionosonde is a swept frequency HF pulsed radar used to monitor the ionosphere. SWS WDC has archived ionogram data from 26 stations, 12 of them are still active at present. An IPS 5D ionosonde had been sounding since May 2012 at Christchurch and until it was closed in April 2014. The 5D vertical sounding ionosondes normally sweep in frequency from about 1 to 21.5 MHz. Frequency step resolution for the 5D is 5kHz, with up to 4095 steps available. The step interval is variable, becoming more coarse at higher frequencies as ionograms are generally displayed on a logarithmic scale. Every five minutes, a Ionogram data file was recorded, cleaned and the cleaned ionogram is transfered to SWS Sydney head office for autoscaling and further analysis. The raw ionogram file is recorded in a DVD monthly, which will be posted to Sydney SWS head office every month. During 15/08/1994 to 22/06/2012, Christchurch also had an IPS 4D ionosonde. and During 15/01/2014 to 01/04/2014, a CADI ionosonde. SWS WDC archives all raw ionogram files and cleaned ionogram files. The Christchurch digital clean ionogram data is available since 05/10/1995, and digital raw ionogram data since 15/08/1994. The Christchurch scaled hourly ionospheric data include parameters of foF2, foF1, FoE, foEs, fbEs, fmin, fxl, f'scaling F/s, M(3000)F2, h'F2, h'F, h'E, h'Es, h'Scaling R/S and Type Es. They are avalable since 06/08/1942 to 24/12/2011. The Christchurch median data of foF2 and M(3000)F2 are available since 05/1939 to 12/2011. The Christchurch station was closed in January 2014.