As another year of stormwatching draws to a close I thought I’d summarise some of the things we have achieved and talked about. So rather than go on at length here’s a word cloud taken from the blog topics over the last year. The larger the text, the more that word featured. Enjoy!
Thanks to all stormwatchers for your sterling efforts in 2011. Here’s to 2012 and another busy year of watching and monitoring our nearest star.
Hi Stormwatchers! The science team may have been a bit quiet on the Stormwatch forum of late but that doesn’t mean we’re not still involved. You may have seen the announcement in the forum pages of our first Stormwatch related paper, published in the Monthly Notices of the Royal Astronomical Society. This focussed on the detection of interplanetary dust from particle trails seen in HI images. If you want to see how your efforts translated to real science, a preview of the paper can be found at; http://arxiv.org/abs/1111.4389 thanks to everyone who spent the time looking at dust! There is a second paper, this time using Stormwatch identifications of solar storms to remove them from the data so that we could look at the effects of high speed solar wind streams arriving at Earth. This paper has been submitted to the Space Weather journal and is currently under review (it is sent to fellow scientists for their comments to ensure that we’re not saying anything incorrect or outrageous). I’ll let you know when I hear more about this. So, we have two publications on the go, with real science informed by your efforts. Thank you so much, we really appreciate your time and efforts but it won’t stop there. Currently we have scientists lined up to take a look at the Stormwatch real-time forecasts generated by you in incoming! and incoming trace-it, and also someone who will be looking at the comet data. This is potentially really exciting as we’re hoping to use observations of the absorption of starlight as the tail drifts across distance starts to tell us something about the particle sizes in the comet tail. Comparing these with observations made in the infra-red by the Herschel spacecraft will hopefully provide some insight into the generation of the very material that we have seen hitting the STEREO spacecraft!
You may also have seen that there was an earth-directed storm that arrived at Earth today without us being able to make a prediction from your clicks. This may have been due to unfortunate gaps in the telemetry from the spacecraft or simply that the spacecraft are now sufficiently far from Earth that making such forecasts for our planet are becoming more challenging. Please keep clicking though, any storm tracked in the science and real-time data is providing us with valuable information on what we will need if we are to accurately predict these storms in future. There is plenty of information left to be mined from our data and we simply wouldn’t be able to do it without you all. Thank you once again for your enthusiasm, efforts and time. It’s such a privilege to be working with you all.
Last month I attended the Astronomy Photographer of the Year awards, held at the Royal Observatory Greenwich, with fellow Solar Stormwatch forum moderator ElisabethB (Els) and fellow Moon Zoo forum moderator Geoff. The overall winner was an amazing photo of Jupiter, Io and Ganymede by Damian Peach showing detail on the two moons – well worth pouring over in high resolution. Some solar astrophotos made the final list this year. In particular Dani Caxete’s photo of the ISS crossing the Sun was one of our favourites as this required nerves of steel to click the shutter at the precise moment.
Here are the solar related photos that made it through to the finals.
“Earth and Space” category runners up:
by Ole C. Salomonsen (Norway)
high resolution version
by Örvar Atli Þorgeirsson (Iceland)
high resolution version
“Our Solar System” category runners up:
|May 7th Hydrogen-Alpha Sun
by Peter Ward (Australia)
high resolution version
|ISS and Endeavour crossing the Sun
by Dani Caxete (Spain)
high resolution version
And here are some that didn’t make the final:
|Another ISS transit
by Thierry Legault
|Entitled “solar keyhole”
by Steven Christenson
|A different kind of transit
|A fabulous sunset
by Stefano De Rosa
|A sun halo
by Niki Giada
Every four hours we pull all the data from incoming trace-it from the database, this give us a massive file with lines looking like.
This is broken down as follows:-
- 20110601_014721_hiB_jmap_999 – the name of the jmap – identifies the latest data in the jmap, the camera and in this case that the data is for the ecliptic plane.
- 99437 – the code number for the user
- 2455712.838797814 the date [as a julian date] here 2011/05/31 08:7:52 GMT
- 43.66942148760331 the elongation angle measured from the image
These last two fields repeat as a pair for the entire profile.
The first process is some simple housekeeping where the result set in each profile is ordered in time and where people have clicked on two traces the line is split into two separate entries; there is a potential pitfall here if two profiles overlap in time and contributors are discouraged from doing this but this process at least allows this data to go forward.
The profiles are then collected into sets arranged by the earliest time in the profile, if from less that 10 degrees elongation, rounded to the nearest hour and split by spacecraft ahead or behind.
The next process counts the number of profiles in each of these bins, but also introduces the concept of a “good” profile that must have a least 3 points and span an elongation range of at least 5 degrees. A 7 hour running window is then computed over the count of good assets. Intervals are then identified where there are more than 10 profiles and the largest value in that range is then identified as an event.
For each event all results meeting the “good” criteria in a 7 hour running window are gathered together into a single file for the fitting process.
The plot shows for August 2010 in red the total number of profiles, in green the total number of “good” profiles and in blue the running total and shows three distinct events on the behind spacecraft and two on ahead.
In my next post I will discuss taking the clicks for a single profile and producing speeds and directions.
Now that you have been analysing the data for some time, we can now start to look at the results that are coming out from your anayses. First off, thank you all for your efforts. I’m genuinely humbled that so many of you have taken time to click on our data.
We have been using the information you have provided via the spot! videos to identify storms and give preliminary values of the their speeds and directions where we can. Jackie has used these numbers to identify the start-times of storms in the jmaps we show you in trace-it (this tells us where to put that pesky blue bar on the jmap to show you which line we are interested in!).
Recently, I’ve been looking at your clicks from Trace-it and thought you’d like to see the preliminary results.
First off is a plot showing the speeds of storms from HI-A;
Here N is the number we see at each speed, so the taller the column, the more storms we see with that particular speed. This distribution certainly is a picture of a quiet solar wind! Most storms are travelling with speeds around 350 km/s but there are a few faster ones…
If we look at the distribution of speeds of storms seen in HI-B we see much the same picture;
Again, most with a relatively slow velocity (350 km/s) while a few have much faster velocities (for comparison, the famous Carrington storm of 1859 travelled at around 2,500 km/s reaching Earth in 17 hours).
So, what do your results tell us? Well, for one thing, it certainly is true that storms can occur at any time of the solar activity cycle. We were amazed to see so many with STEREO at a period when the Sun was quieter than at any time in the last century! The fact that storms still occur means that there are still changes occuring in the Sun’s magnetic cycle. Some scientists think that solar storms are the mechanism by which the magnetic field continues to evolve on the Sun. Even if the field is so weak on the solar disk that there are no obvious sun-spots. The fact that we can see storm activity during this period of extreme quiet is interesting evidence for this continued evolution. The fact that most were no faster than the solar wind would have meant that without spacecraft like STEREO and ACE they would probably have gone largely undetected.
I also plotted out the angles of the storm trajectories with respect to the Earth for HI-A;
We have seem storms over a wide variety of angles, as we’d expect (they should be emitted in random directions as the Sun doesn’t pick on the Earth out of spite!). The fact that the distribution peaks at an angle of zero (headed Earthward) is likely to be due to the evolving geometry of the mission as the spacecraft head away from Earth. The distribution for HI-B looks similar;
So, what do these first results tell us? Well, for starters it confirms that you are doing a fantastic job! It also confirms that there have been few spectacularly fast storms. Our next steps will be to compare the data from both spacecraft to see if they agree with each other (!) and update the speed and directions for the storms you have already identified in ‘Spot’ but for which we couldn’t estimate the speed. Then we can pick out (say) the Earth-directed ones and take a look at them in more detail.
We could still use your help in trace-it though so please keep looking at our data. The more clicks we have, the more accurately we can determine each storm’s characteristics. Eventually we hope to learn how fast each storm expands into space in all directions, how it is slowed or accelerated by the solar wind and how we can use these corrections to better predict the arrival of such storms at Earth.
Thanks again for all your time, effort and enthusiasm. Without you we would not be learning as much as we are nor learning it as fast.
Finally, a little after 1 year from the launch of SSW, we are finding ourselves in the exciting position of having lots of interesting science data to revel in.
I began my first study by looking into the details of the circular storm thread. At first, I thought about drawing circles on top of each frame in the same manner as the initial example shown in my blog. But the shear large number of events that were being identified made this too difficult. So in the spirit of finding a method of analysis that can be repeated quickly and easily for all of the new storms being seen, I started to use the tracks found in J-maps.
I thought that if the front and back edges of these ideal circular storms can be identified with a dark cavity in the middle, then each storm would display 2 tracks in the J-maps. This means that if I measure the distance between each track then I can measure the size of the storm continuously as it moves away from the Sun. Also, if I measure the angle between the top edge – Sun – bottom edge then I can get an estimate of the vertical height of the storm continuously. These two pieces of information allowed me to experiment with 4 of the storms identified in the forum within the circular storm thread.
Below is a picture I created that shows the estimated shape of the storm as it moves away from the sun. The blue shaded region is the average estimated size from the 4 storms analysed. The red shape is an average estimate made from hundreds of storms- but to do this requires mixing statistical estimates from cameras close to the Sun and 1D measurements made when a storm travels over a spacecraft (in situ observations). Below, the Sun is shown as 5 times the real size for clarity, and the axes are shown in solar radii (Rs). Earth is nominally positioned at 215 Rs.
I have now submitted these results for publication, so I would like to thank you for all the effort and hard work that you have put into getting this project off the ground. So if you havent already done so, you still have time to register yourself as officially contributing to the work here !!! 🙂
Well like Chris said in his blog earlier, I’m now off to analyse all the lovely science data from the trace-it tasks. So with a bit of luck you guys will start to hear more regular updates as the science team start ploughing through the results.
Well done everyone and keep up with all the work, as we could not have done it without you.
We’ve been meeting with various people lately who are all interested in using your data analysis in their research. As a result, I thought I’d update you on our plans.
Firstly, thanks to everyone who has been contributing to the real-time forecasting of space-weather events. With the spacecraft now heading towards the far side of the Sun from the Earth, I don’t know how much longer we will be able to forecast Earth-impacting storms so it’s great that we are able to hone our prediction skills while we can! This is all very useful information and will provide valuable insight into designing the follow-on solar missions that will attempt to provide on-going space-weather forecasts. In order to assess how successful we have been with our real-time forecasts, researchers at Imperial College in London will be scrutinising your clicks and comparing our predictions with those from the higher resolution science data. The real-time beacon is much lower in resolution than the science data (used in the trace-it and spot games) and we want to know if that affects our ability to make accurate forecasts. If it does, that is a strong argument to improve the resolution of future real-time space-weather missions. If not, then we can save money by sticking with what we have! Either way, we want to learn what we can from your analysis of the STEREO real-time data.
In addition to the real-time analysis, Neel Savani, one of our Stormwatch regulars, is going to analyse the science data from trace-it and produce some catalogues of the storms we have seen so far. With all your efforts, we should be able to not only provide estimates of speeds and directions but also look at how each storm expands as it travels out from the Sun.
… and what about the dust impacts? I hear you cry. Well, that paper is very close to being submitted but we’re still trying to understand exactly what’s going on there. I will be sure to let you know as soon as we find out!
Meantime, it looks like Neel could win the race for the fist stormwatch paper to be submitted. those of you who have been looking at the forum will have seen that Neel set up a mini-project asking you to look out for perfectly circular storms. Well, it seems he’s been busy preparing a publication on that too.
I haven’t mentioned some of the games here but don’t think that means we’re not using the data from them. We’re just starting to pick through the mountain of information. We’ll get to the others in good time.
In the next few months, we will see the fruits of your labours being put out to the sceintific community for scrutiny. Thank you all so much for your efforts, however much you have been able to do. It’s all much appreciated and we couldn’t have done any of this without you.