Whether there are signatures of ground conditions in ionospheric spread-F occurrence

Ionospheric perturbations are dynamically forced from both above and below, the latter is more important in mid- and low latitudes. It is well known that most of the wave-like disturbances originate from the lower atmosphere. In this report, we deal with two issues. The first is whether there are signatures of couplings between ionospheric spread-F and surface meteorological conditions; the second is whether very short lived spread-F-like phenomena exist in ionosphere which is closely connected with some sudden changes of ground conditions such as typhoon landing and great earthquakes. Observational examples are provided and brief discussions also made. Particularly, it is shown that the geomagnetic field disturbances occurred simultaneously with these transient ionospheric phenomena caused by the magnitude 9.0 Earthquake occurred in Japan on March 11, 2011. Examples provided in this report all occurred in the Asia Sector mid-latitudes, It is interesting whether this is only regional feature or a phenomenon in general for other Sectors and different latitudes.