Saša said:
There is indeed a bias toward increase of observational time in IMO Network data.
It seems that the guys in IMO Network have been competing among themselves who would catch more meteors.
In the attached plot, it can be seen the density of observed meteors, which shows just fluctuations over years, which can maybe be attributed to weather conditions in particular year. No clear trend present.
After looking at the table Pashalis sent about SonotaCo data, especially at Tokio1 station data for which SonotaCo wrote it was operational every night, it can be seen that the numbers of observed meteors drastically increased in 2012 with respect to previous years for every camera of that station. Similar thing, that all cameras of a station observed an increase of meteors (although not so large as Tokio 1) happened only with 1 other station (Chiba 2, operated by Aba). It could be that there was really more meteors that year, but it could also be that they had increased their observational time (or some other reason like better weather). The IMO Network data also state that they were operational for every night of the year, but the observational time differed among years. Therefore, I wouldn't consider Japanese data reliable either, only on the basis of operating every night, in the sense of no bias being involved. IMO, proper way would be to check the observed meteor density, like for IMO Network, for all stations and all cameras, regardless when they were active.
As for the AMS data, it was said in another thread that the numbers of reports per confirmed fireball increased
http://cassiopaea.org/forum/index.php/topic,29604.msg471791.html#msg471791
making the straightforward conclusion that the number of fireballs increased, in absolute terms, a bit arguable, since there is no clear evidence what has been the effect of increase of number of reports on the increase of number of fireballs. In other words, it is not clear if there is a bias involved there as well.
Bottom line, as I see it, is that there are more meteors/fireballs observed/reported over the years. However, what is the exact reason for it, it's not so clear (except when the link between the observational time and number of observed meteors is evident). I would be careful with categorically claiming that there are really more and more fireballs in the skies, as not to fall into confirmation bias trap that is not so rare among scientists.
As a side note, I also checked the number of highest energy cosmic rays (reconstructed energy > 1019 eV) observed with 3000 km2 array in 2009-2013 period. No significant change/trend in that time period was observed.
