MSTIDs activity data, Ionosonde data and time distribution plots over the China sector during the summer of 2014-2018

MSTIDs activity data (MSACT) :  the detrended TEC (dTEC) is obtained by extracting disturbances from TEC using a bandpass filter at the typical periods of MSTIDs (10-60 minutes). Then, the average relative amplitude is computed within a specific spatiotemporal grid (a spatial grid resolution of 1° × 1° and a temporal resolution of 15 minutes).

Ionosonde data: a total of 12 mid-latitude stations are involved . The ionosonde data covers the years from 2014 to 2018 and the time resolution is 1 hr, including foF2, h'F, foEs, and fbEs. Spread F, exhibiting spreading echo traces in the F region height on ionograms, is categorized into FSF and RSF for statistical recording. FSF can be detected by trace broadening in frequency near the critical frequency, while RSF can be identified by trace broadening in range away from the critical frequency.

Plots: the time distribution of MSTIDs activity and FSF occurrence at a given station in a year (2014-2018).The heatmap represents MSTIDs activity, while the blue triangles indicate the occurrence of FSF.