Fireballs over Japan

Niall · Jan 14, 2014

Could someone who can read Japanese take a look through this website and tell me if they have any statistics - like charts, logs, tables or graphs - on the meteor fireballs observed from Japan?

http://sonotaco.jp/

I'm especially interested in knowing how many fireball events have been reported each year, as far back as they began keeping records.

Palinurus · Jan 14, 2014

Hi Kniall,

Although I cannot read Japanese, I found that most info is available in English.

They have an overview of observations (automatically generated) here.

SonotaCo Network Simultaneously Observed Meteor Data Sets

This page contains simultaneously observed meteor data sets reduced from observations by the SonotaCo Network Members.
Note of each file shows the observers and the outline of the sets.

This can be downloaded and used freely for non-profit purpose of scientific research or academic affairs.
For the publishing of the results using these data sets, you should use credit below.
"SonotaCo Network Simultaneously Observed Meteor Data Sets SNM20xxx", http://sonotaco.jp/doc/SNM/

They cover 01-01-2007 through 12-31-2012 in yearly parts, i.e. six sets in total. The numbers of meteors are in the table and each year has a text file which differentiates the observations like for instance 2007 or 2012. Most data are raw materials.

Overview of the numbers (meteors only):

2007: 19274
2008: 19436
2009: 25940
2010: 25858
2011: 23772
2012: 27231

There's an English forum here. Didn't check out the posts, though.

For 2007-2008 there is a separate page here with a PDF file in English stating their methods of observation, computation and such:

abstract said:
WGN, the Journal of the IMO 37:2 (2009) 55

Ongoing Meteor Work
A meteor shower catalog based on video observations in 2007–2008
SonotaCo

A new meteor shower catalog was established from two years of
continuous video observations based on almost
240,000 single-station observations by more than 100 video
cameras operated at 25 stations in Japan. 39208
meteor orbits were computed from them as qualified multi-station
observations. From this sample, 38 meteor
showers were obtained as the result of applying a uniformized
method of clustering in the four-dimensional
space of appearance in Solar longitude, radiant position, and
geocentric velocity. The full set of showers in the
new catalog covered 37% of all meteors. No other concentration
was confirmed from the remaining 63%. The
catalog is the first one based on long term, wide area, multi-station
video observations, and shows the recent real
activity for all major meteor showers that are optically observable
from northern hemisphere. Eleven showers
have been added to the list of meteor showers of the IAU Meteor
Data Center (MDC).

It wouldn't hurt when some one else still inspected the rest of the site in Japanese, I think.

Hope this helps a bit. :)

EDITED to add: From what I gathered, it's doubtful their network covers the whole of Japanese territory.

Aya · Jan 15, 2014

Kniall said:
Could someone who can read Japanese take a look through this website and tell me if they have any statistics - like charts, logs, tables or graphs - on the meteor fireballs observed from Japan?

http://sonotaco.jp/

I'm especially interested in knowing how many fireball events have been reported each year, as far back as they began keeping records.

On the forum of the website, people are posting their random observations on meteorites and fireballs, but I don't see any overall statistics of it.

Here is a different website that I found.

On the English title it says "Recent Meteorites and Meteoritic Fireballs in Nippon (after 1985)"
but in the Japanese title it says: "The recent fireballs that hit and are sure to be hit in Japan. (after1985)"
http://www5e.biglobe.ne.jp/~shibaya/meteorites/meteoritesE.html

Currently, I am not finding any better websites that has the statistics of fireballs observed in Japan. I think I need to do a lot of digging, maybe some experts have taken statistics but with a quick browsing, I cannot find anything.
Or we end up needing to make statistics on our own, if that's what you are intending to do, I can help you with that.

Are you also looking for observations on sprites?
I can count the sightings from SontataCo.JP and add if I can find more information from different websites, what do you think?

Niall · Jan 15, 2014

Palinurus said:
Overview of the numbers (meteors only):

2007: 19274
2008: 19436
2009: 25940
2010: 25858
2011: 23772
2012: 27231

Interesting, their data shows an increase, though perhaps not as steep an increase as the AMS data suggests.

The Japanese fireball network has the best publicly-available fireballs data I've seen yet. This paper they published is interesting:

WGN, the Journal of the IMO 37:2 (2009) 55

Ongoing Meteor Work

'A meteor shower catalog based on video observations in 2007–2008'

SonotaCo

A new meteor shower catalog was established from two years of continuous video observations based on almost 240,000 single-station observations by more than 100 video cameras operated at 25 stations in Japan. 39208 meteor orbits were computed from them as qualified multi-station observations. From this sample, 38 meteor showers were obtained as the result of applying a uniformized method of clustering in the four-dimensional space of appearance in Solar longitude, radiant position, and geocentric velocity. The full set of showers in the new catalog covered 37% of all meteors. No other concentration was confirmed from the remaining 63%. The catalog is the first one based on long term, wide area, multi-station video observations, and shows the recent real activity for all major meteor showers that are optically observable from northern hemisphere. Eleven showers have been added to the list of meteor showers of the IAU Meteor Data Center (MDC).

Their work has resulted in 11 new meteor showers being added to the list of named showers in recent years, although there are probably more...

For this study we used the SonotaCo Network’s published observational results for the period 2007 January 1 to 2009 January 1 (731 nights). This data was compiled by 25 stations using more than 100 cameras. The totals are listed in Table 1...

For comparison, NASA's All-Sky Camera Network consists of just 12 cameras that cover only a tiny portion of US airspace.

Table 1 - Totals of the observations in 2007–2008.

Number of single-station meteors: 293702
Number of qualified single-station meteors: 244247
Number of single-station observations composing simultaneous observations: 114026
Number of meteors qualified for multi-station observation: 39208
Average number of simultaneous observations per meteor: 2.93 cameras/meteor
Average number of qualified meteors per night: 53.6 meteors/night
Number of nights with >100 qualified meteors: 120 nights / 2 years
Number of nights with no meteor observed: 133 nights / 2 years
Top 6 nights which had most meteors (UT):

2007/12/14 (1051 meteors)

2007/08/12 (845 meteors)

2007/12/13 (796 meteors)

2007/08/13 (700 meteors)

2007/10/20 (655 meteors)

2008/12/14 (603 meteors)

If I understand this part of the paper correctly...

abstract said:
The full set of showers in the new catalog covered 37% of all meteors. No other concentration was confirmed from the remaining 63%.

...then two-thirds of observed meteor/fireballs over Japan during that period (2007-2008) do not belong to named meteor showers. That's a whole lot of unknowns entering the atmosphere!

This from the conclusion:

The difference between this result and the established IAU [International Astronomical Union] list is not small. Further research needs to be done for 14 new showers which are not in the IAU list. Ten showers have been included as new entries in the working list of the IAU MDC. For those 26 showers in the IAU list which were not confirmed by this study, a careful study of the activity in recent and future years should be done.

One of the results of this study, the almost smooth distribution of sporadic meteors, suggests the possibility of finding further minor showers or discovering a mechanism responsible for changing sporadic meteor orbits. Since sporadic meteors can only be obtained by subtraction of the meteors of known showers, however, we need to know more details about the distribution of shower meteors.

Although the abstract says 11 new meteor streams have been added to the official IAU list, as they explain in their methodology regarding clustering, it's hard to tell which meteor is part of which stream from their limited vantage point. Which is why they suggest at the end that there ought to be All-Sky Camera fireball networks all over the world. But there isn't because budgets are needed to start wars and distract people.

In the meantime we're left with a couple of tantalising possibilities: either the background rate of meteor activity - 'sporadic meteor fireballs', with no connection to known meteor showers - is increasing because we're entering an area of space with higher quantities of comet debris... and/or higher quantities of comet debris have entered the solar system.

Pierre · Feb 16, 2014

Aya said:
On the forum of the website, people are posting their random observations on meteorites and fireballs, but I don't see any overall statistics of it.

Here is a different website that I found.

On the English title it says "Recent Meteorites and Meteoritic Fireballs in Nippon (after 1985)"
but in the Japanese title it says: "The recent fireballs that hit and are sure to be hit in Japan. (after1985)"
http://www5e.biglobe.ne.jp/~shibaya/meteorites/meteoritesE.html

Currently, I am not finding any better websites that has the statistics of fireballs observed in Japan. I think I need to do a lot of digging, maybe some experts have taken statistics but with a quick browsing, I cannot find anything.
Or we end up needing to make statistics on our own, if that's what you are intending to do, I can help you with that.

Are you also looking for observations on sprites?
I can count the sightings from SontataCo.JP and add if I can find more information from different websites, what do you think?

I compiled the data posted above into a table and chart (see below).

The linear regression indicates an average annual increase of 8%.

I want to include those graphs in the book I'm currently finalizing but first I would like to know if the number of observation stations has changed over the period 2007-2012. So we can know if the increase in number of observations is due to increase in number of stations and/or increase in actual fireballs?

Also did the SonotaCo publih their figures for 2013?

Cosmos · Feb 16, 2014

Pierre said:
Aya said:

On the forum of the website, people are posting their random observations on meteorites and fireballs, but I don't see any overall statistics of it.

Here is a different website that I found.

On the English title it says "Recent Meteorites and Meteoritic Fireballs in Nippon (after 1985)"
but in the Japanese title it says: "The recent fireballs that hit and are sure to be hit in Japan. (after1985)"
http://www5e.biglobe.ne.jp/~shibaya/meteorites/meteoritesE.html

Currently, I am not finding any better websites that has the statistics of fireballs observed in Japan. I think I need to do a lot of digging, maybe some experts have taken statistics but with a quick browsing, I cannot find anything.
Or we end up needing to make statistics on our own, if that's what you are intending to do, I can help you with that.

Are you also looking for observations on sprites?
I can count the sightings from SontataCo.JP and add if I can find more information from different websites, what do you think?

Click to expand...

I compiled the data posted above into a table and chart (see below).

The linear regression indicates an average annual increase of 8%.

I want to include those graphs in the book I'm currently finalizing but first I would like to know if the number of observation stations has changed over the period 2007-2012. So we can know if the increase in number of observations is due to increase in number of stations and/or increase in actual fireballs?

Also did the SonotaCo publih their figures for 2013?

I'm currently on it, to find out if the number of observation stations that were used in each year for the data above varies.
As of now I've compared the years 2007, 2008 and 2009 in that respect (The rest till 2012 I'll do the next coming days) and it looks like the numbers of observation stations that were used to come up with those numbers above vary significantly through the time frame I've looked at so far. So I don't think we can get a reliable statistical data set from the numbers that were posted above, to decide if there was really an increase or not...

I've looked through the data carefully now and I think there could be another way I could filter out statistical reliable data from 2009 onwards. I can't include 2007 and 2008 as of yet, since the data they shared for those two years does not specify what cameras were used so that I can compare it to the years of 2009 - 2012 which display this crucial data.

What I'm trying to do, is to finish the data set I mentioned above until the year of 2012:

Pashalis said:
I'm currently on it, to find out if the number of observation stations that were used in each year for the data above varies.
As of now I've compared the years 2007, 2008 and 2009 in that respect (The rest till 2012 I'll do the next coming days) and it looks like the numbers of observation stations that were used to come up with those numbers above vary significantly through the time frame I've looked at so far.

When I have finished that, I can see which observation stations were active throughout the whole period of 2007 - 2012. Then when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"

That should give us a real indicator. But then another question emerges: Can those camera networks also detect fireballs that are behind clouds?. Lets propose for example that 2009 was pretty cloudy throughout the year in Japan and 2010 was pretty cloudless compared to that year respectively on those camera stations. Would that effect the reliability of the data, I will figure out soon? I guess that could be the case? So do we know if those cameras can also detect fireballs when it is cloudy? Can somebody figure that out?, If the cameras can not detect fireballs when it is cloudy, I think we will have to figure out how cloudy each year from 2007 until 2012 was in Japan on those camera stations. If there is not much difference throughout those years, or if the cameras can detect them through the clouds we might finally have a real indicator of what is going on in the skies, respectively in those areas that are covered by those cameras in Japan, throughout this time frame.

Pashalis said:
I can't include 2007 and 2008 as of yet, since the data they shared for those two years does not specify what cameras were used so that I can compare it to the years of 2009 - 2012 which display this crucial data.

Maybe once I'm finished with my data set, we could contact them and ask if (with the list at hand, that I will create) if the cameras that were used throughout 2009 -2012 were also active in 2007 and 2008? A response to that could also enable me to include 2007 and 2008 into the table, which would be nice...

I'm also wondering when the data of 2013 will be available? Maybe we can ask for that too? That would really be handy...

Human · Feb 17, 2014

Pierre said:
I want to include those graphs in the book I'm currently finalizing but first I would like to know if the number of observation stations has changed over the period 2007-2012. So we can know if the increase in number of observations is due to increase in number of stations and/or increase in actual fireballs?

Also did the SonotaCo publish their figures for 2013?

I've sent them an e-mail asking about that and any additional info they can provide.

Human · Feb 17, 2014

Their answer came.

SonotaCo said:
Is there information about meteors in year 2013, or before 2007?

Click to expand...

As for 2013, the SNM2013 is scheduled to be made in coming March. Our observation began at 2003, and the data hub web site was made at Dec/2004.
So a bit more results are existing in our forum, But the they were not collected nor arranged.

What is the number of operating stations during particular year?

Click to expand...

There are notes (20xx.txt) file on the page below. There, stations and their observation counts are listed. http://sonotaco.jp/doc/SNM/index.html

I would be grateful for any additional information about meteors/fireballs you can provide.

Click to expand...

Well, please make questions more specifically. Which field are you interested in? Observation methods? Showers? Orbits? Dynamics? ..?

I've sent them another mail explaining and asking things Pashalis mentioned in his post.

Human · Feb 18, 2014

Here is the exchange. Images are attached below.

SonotaCo said:
Saša said:

I'm interested in establishing if there is a correlation between the number
of observed meteors and deployed/operational stations, and if so what is the
impact on the increase of the number of meteors over years.

I've checked the notes files you kindly directed me to, but the breakdown to
individual stations is not the same for 2007-2008 and 2009-2012 period,
that's why I'm inquiring about the overall/total number of operational
stations each year.

Regarding the additional info, I'm interested in your observational method,
in particular, what would be its efficiency with respect to atmospheric
conditions (e.q. differences between night and day, clear and cloudy sky,
etc.).

Click to expand...

Hi

Thank you for explanation.

Total count of optical observation is strongly affected by weather
condition and Moon age of the peak of some major meteor showers.
See major_shower_count.png. It is a trial count of 2013.
There were 25228 meteors simultaneously observed in 2013.
And the number of major 5 showers are 3042,1798,590,458,426.
See those of 2009 and 2010. Count of each shower varies very much.
So I think it is difficult to say something from overall count.

Regards,
SonotaCo

It is said, in the reply, that the meteor number for 2013 is 25228 (except that, I don't quite understand the remainder of the message).
After checking picture/table counts.png I would suggest to neglect (remove) two points for 2007 and 2008. I think that the consistency can't be established between measurements of 2007-2008 and 2009-2013 time periods, thus the data of those two periods can't be correctly/properly compared.
The number of meteors in 2009-2013 period looks pretty flat, i.e. constant, to me.

If there is something more that should be asked, drop a line, so I can send it to SonotaCo. Or send it directly. :)

Cosmos · Feb 18, 2014

Pashalis said:
Pierre said:

Aya said:

On the forum of the website, people are posting their random observations on meteorites and fireballs, but I don't see any overall statistics of it.

Here is a different website that I found.

On the English title it says "Recent Meteorites and Meteoritic Fireballs in Nippon (after 1985)"
but in the Japanese title it says: "The recent fireballs that hit and are sure to be hit in Japan. (after1985)"
http://www5e.biglobe.ne.jp/~shibaya/meteorites/meteoritesE.html

Currently, I am not finding any better websites that has the statistics of fireballs observed in Japan. I think I need to do a lot of digging, maybe some experts have taken statistics but with a quick browsing, I cannot find anything.
Or we end up needing to make statistics on our own, if that's what you are intending to do, I can help you with that.

Are you also looking for observations on sprites?
I can count the sightings from SontataCo.JP and add if I can find more information from different websites, what do you think?

Click to expand...

I compiled the data posted above into a table and chart (see below).

The linear regression indicates an average annual increase of 8%.

I want to include those graphs in the book I'm currently finalizing but first I would like to know if the number of observation stations has changed over the period 2007-2012. So we can know if the increase in number of observations is due to increase in number of stations and/or increase in actual fireballs?

Also did the SonotaCo publih their figures for 2013?

Click to expand...

I'm currently on it, to find out if the number of observation stations that were used in each year for the data above varies.
As of now I've compared the years 2007, 2008 and 2009 in that respect (The rest till 2012 I'll do the next coming days) and it looks like the numbers of observation stations that were used to come up with those numbers above vary significantly through the time frame I've looked at so far. So I don't think we can get a reliable statistical data set from the numbers that were posted above, to decide if there was really an increase or not...

I've looked through the data carefully now and I think there could be another way I could filter out statistical reliable data from 2009 onwards. I can't include 2007 and 2008 as of yet, since the data they shared for those two years does not specify what cameras were used so that I can compare it to the years of 2009 - 2012 which display this crucial data.

What I'm trying to do, is to finish the data set I mentioned above until the year of 2012:

Pashalis said:

I'm currently on it, to find out if the number of observation stations that were used in each year for the data above varies.
As of now I've compared the years 2007, 2008 and 2009 in that respect (The rest till 2012 I'll do the next coming days) and it looks like the numbers of observation stations that were used to come up with those numbers above vary significantly through the time frame I've looked at so far.

Click to expand...

When I have finished that, I can see which observation stations were active throughout the whole period of 2007 - 2012. Then when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"

That should give us a real indicator. But then another question emerges: Can those camera networks also detect fireballs that are behind clouds?. Lets propose for example that 2009 was pretty cloudy throughout the year in Japan and 2010 was pretty cloudless compared to that year respectively on those camera stations. Would that effect the reliability of the data, I will figure out soon? I guess that could be the case? So do we know if those cameras can also detect fireballs when it is cloudy? Can somebody figure that out?, If the cameras can not detect fireballs when it is cloudy, I think we will have to figure out how cloudy each year from 2007 until 2012 was in Japan on those camera stations. If there is not much difference throughout those years, or if the cameras can detect them through the clouds we might finally have a real indicator of what is going on in the skies, respectively in those areas that are covered by those cameras in Japan, throughout this time frame.

Pashalis said:

I can't include 2007 and 2008 as of yet, since the data they shared for those two years does not specify what cameras were used so that I can compare it to the years of 2009 - 2012 which display this crucial data.

Click to expand...

Maybe once I'm finished with my data set, we could contact them and ask if (with the list at hand, that I will create) if the cameras that were used throughout 2009 -2012 were also active in 2007 and 2008? A response to that could also enable me to include 2007 and 2008 into the table, which would be nice...

I'm also wondering when the data of 2013 will be available? Maybe we can ask for that too? That would really be handy...

Ok, I've finished the data collection for the years of 2009, 2010, 2011 and 2012 now.

This turns out to be correct:

Pashalis said:
[...] So I don't think we can get a reliable statistical data set from the numbers that were posted above, to decide if there was really an increase or not...[...]

But the data I've finished now, will give us a real statistical (more or less) reliable trend for those years, mentioned here:

Pashalis said:
[...]I think there could be another way, I could filter out statistical reliable data from 2009 onwards. [...]

[..]when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"[...]

In other words, the data from all of those camera stations combined (totaled up), throughout those years (2009-2012), gives us now the trend of what was recorded by those cameras (number of recorded sky activity).

Here it is:

https://docs.google.com/spreadsheet/ccc?key=0AosqCCf-0a_XdDNqZ1ZXQ1FLYXRpdFd3ZXRGVTBIYUE&usp=drive_web#gid=0

So now it would be great if we could get the data from the above table also for the years 2007, 2008 and 2013!
Maybe Saša, you could ask for that?

We would simply need all the available data for the years 2007, 2008 and 2013 from the tablelist above (which isn't there yet, because we don't have them)...

If we have this data, we would then be able to readjust the data above, so that we can get the whole trend from 2007 - 2013... Which would be really nice... also in comparison to the AMS data...

So the trend for 2009 - 2012 is as follows:

That is a 19,64 % increase, within the time frame of 2009 - 2012...

And that is how it looks like in a chart:

So it would really be nice if we could get the data for 2007, 2008 and 2013...

Palinurus · Feb 18, 2014

Saša said:
(except that, I don't quite understand the remainder of the message).

SonotaCo said:
And the number of major 5 showers are 3042,1798,590,458,426.

Hi Saša,

Have a look here: _http://meteorshowersonline.com/major_meteor_showers.html

Gem = Geminids
Per = Perseids
etA = Eta Aquarids
Hyd = Hydra (?) may be Ursids
Com = ??
Ori = Orionids
Leo = Leonids
sTa = Taurids
nTa = Taurids
Qua = Quadrantids
Lyr = Lyrids

That's what I understood of it. They seem most interested in observing these major meteor showers in their annual sequence, year in year out.

Human · Feb 18, 2014

Palinurus said:
Hi Saša,

Have a look here: _http://meteorshowersonline.com/major_meteor_showers.html

Gem = Geminids
Per = Perseids
etA = Eta Aquarids
Hyd = Hydra (?) may be Ursids
Com = ??
Ori = Orionids
Leo = Leonids
sTa = Taurids
nTa = Taurids
Qua = Quadrantids
Lyr = Lyrids

That's what I understood of it. They seem most interested in observing these major meteor showers in their annual sequence, year in year out.

Thanks.
That's the impression I got also and that they observe those showers only during night-time. Which makes me wonder how useful their data for our comet counting really are?

Pashalis said:
Ok, I've finished the data collection for the years of 2009, 2010, 2011 and 2012 now.

This turns out to be correct:

Pashalis said:

[...] So I don't think we can get a reliable statistical data set from the numbers that were posted above, to decide if there was really an increase or not...[...]

Click to expand...

But the data I've finished now, will give us a real statistical (more or less) reliable trend for those years, mentioned here:

Pashalis said:

[...]I think there could be another way, I could filter out statistical reliable data from 2009 onwards. [...]

[..]when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"[...]

Click to expand...

In other words, the data from all of those camera stations combined (totaled up), throughout those years (2009-2012), gives us now the trend of what was recorded by those cameras (number of recorded sky activity).

Does that include multiple observations (by multiple cameras) of the same meteor?
If yes, that resembles to number of people reporting fireballs in AMS records.

Pashalis said:
Here it is:

https://docs.google.com/spreadsheet/ccc?key=0AosqCCf-0a_XdDNqZ1ZXQ1FLYXRpdFd3ZXRGVTBIYUE&usp=drive_web#gid=0

I don't see the table, just the link, which asks me for permission to see what's "behind" it. I've requested for account with my gmail.

Pashalis said:
So now it would be great if we could get the data from the above table also for the years 2007, 2008 and 2013!
Maybe Saša, you could ask for that?

No problemo :)
I just need to see which data you need, though.

We would simply need all the available data for the years 2007, 2008 and 2013 from the tablelist above (which isn't there yet, because we don't have them)...

If we have this data, we would then be able to readjust the data above, so that we can get the whole trend from 2007 - 2013... Which would be really nice... also in comparison to the AMS data...

So the trend for 2009 - 2012 is as follows:

That is a 19,64 % increase, within the time frame of 2009 - 2012...

And that is how it looks like in a chart:

So it would really be nice if we could get the data for 2007, 2008 and 2013...

Using your data, it's 6.17% average yearly relative change (increase).

Pierre · Feb 18, 2014

Sasha said:
I've sent them an e-mail asking about that and any additional info they can provide.

Thanks for taking the time to contact SonotaCo :)

Sasha said:
It is said, in the reply, that the meteor number for 2013 is 25228 (except that, I don't quite understand the remainder of the message).

Don't they mean the number of observed meteors for each of the 5 showers?

Pashalis said:
When I have finished that, I can see which observation stations were active throughout the whole period of 2007 - 2012. Then when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"

That sounds like a good start: yearly meteor counts over a fixed number of cameras

Sasha said:
The number of meteors in 2009-2013 period looks pretty flat, i.e. constant, to me.

The number of "single observations" seems quite flat indeed: around 170,000/year though the number of "simultaneous observations" (one same meteor observed by several stations) seems to increase slightly. Does this mean that big size meteors (noticed by several stations) is on the rise?

Pashalis said:
In other words, the data from all of those camera stations combined (totaled up), throughout those years (2009-2012), gives us now the trend of what was recorded by those cameras (number of recorded sky activity).

Same cameras for 2009,2010,2011 and 2012?

Can those camera networks also detect fireballs that are behind clouds?. Lets propose for example that 2009 was pretty cloudy throughout the year in Japan and 2010 was pretty cloudless compared to that year respectively on those camera stations. Would that effect the reliability of the data, I will figure out soon? I guess that could be the case? So do we know if those cameras can also detect fireballs when it is cloudy?

You're opening a can of worms here. Difficult to know the cloudiness over Japan, even more difficult to know the cloudiness over the stations, difficult to know also if the cameras had some downtime (failure, maintenance, operators....)

I guess that cloudiness can only affect negatively meteor counts, although the biggest ones might remain observable. This being said world cloudiness has been increasing over the past years, but despite this trend AMS and SonotaCo annual number of observed meteors is growing.

Sasha said:
Pashalis said:

Here it is:

https://docs.google.com/spreadsheet/ccc?key=0AosqCCf-0a_XdDNqZ1ZXQ1FLYXRpdFd3ZXRGVTBIYUE&usp=drive_web#gid=0

Click to expand...

I don't see the table, just the link, which asks me for permission to see what's "behind" it. I've requested for account with my gmail.

Same here.

Human · Feb 18, 2014

Pierre said:
Sasha said:

It is said, in the reply, that the meteor number for 2013 is 25228 (except that, I don't quite understand the remainder of the message).

Click to expand...

Don't they mean the number of observed meteors for each of the 5 showers?

I haven't understood it in that way. Check the table they sent me (counts.png at the bottom). It's the overall number of simultaneously observed meteors (numbers which you plotted in your bar chart).

Pierre said:
Sasha said:

The number of meteors in 2009-2013 period looks pretty flat, i.e. constant, to me.

Click to expand...

The number of "single observations" seems quite flat indeed: around 170,000/year though the number of "simultaneous observations" (one same meteor observed by several stations) seems to increase slightly. Does this mean that big size meteors (noticed by several stations) is on the rise?

I don't agree.
If points for 2007 and 2008 are neglected, since they're obtained with somehow different method (possibly less active stations than in later years), and which are quite similar to each other in their value, the numbers that remain, if you add a 25228 bar for 2013, don't show any significant increase.

Cosmos · Feb 18, 2014

Pierre said:
Pashalis said:

When I have finished that, I can see which observation stations were active throughout the whole period of 2007 - 2012. Then when I have those stations, I then can compare each station through those years and see what cameras were used throughout that time frame (unfortunately only from 2009 -2012, as of yet). I will then be able to add up all those reliable data for each year and the result will give us the following data: "Number of all observed events added up from all camera station that are listed in the source list below, throughout 2009 -2012"

Click to expand...

That sounds like a good start: yearly meteor counts over a fixed number of cameras

I guess that is the only way we can get out fairly accurate statistical data from that Japanese website...

Pierre said:
Pashalis said:

In other words, the data from all of those camera stations combined (totaled up), throughout those years (2009-2012), gives us now the trend of what was recorded by those cameras (number of recorded sky activity).

Click to expand...

Same cameras for 2009,2010,2011 and 2012?

Yes...

Pierre said:
Pashalis said:

Can those camera networks also detect fireballs that are behind clouds?. Lets propose for example that 2009 was pretty cloudy throughout the year in Japan and 2010 was pretty cloudless compared to that year respectively on those camera stations. Would that effect the reliability of the data, I will figure out soon? I guess that could be the case? So do we know if those cameras can also detect fireballs when it is cloudy?

Click to expand...

You're opening a can of worms here. Difficult to know the cloudiness over Japan, even more difficult to know the cloudiness over the stations, difficult to know also if the cameras had some downtime (failure, maintenance, operators....)

I guess that cloudiness can only affect negatively meteor counts, although the biggest ones might remain observable. This being said world cloudiness has been increasing over the past years, but despite this trend AMS and SonotaCo annual number of observed meteors is growing.

Indeed it is a can of worms!

Pierre said:
Sasha said:

Pashalis said:

Here it is:

https://docs.google.com/spreadsheet/ccc?key=0AosqCCf-0a_XdDNqZ1ZXQ1FLYXRpdFd3ZXRGVTBIYUE&usp=drive_web#gid=0

Click to expand...

I don't see the table, just the link, which asks me for permission to see what's "behind" it. I've requested for account with my gmail.

Click to expand...

Same here.

Should be working now...

Fireballs over Japan

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