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.
The science bit- By looking at the changing shape we can study how elliptical or deformed the storms become and how fast this rate of change is. By looking at where they start disappearing, it may give us some insight into the practical limitations of investigating the full structure of these storms- or perhaps, into the sensitivity and resolution of the camera.
So, I have a question for all you Stormwatchers- What is the farthest away from the Sun you can trace the full shape of a Storm?
So to clarify, if you look at a single frame from a movie of a storm, what is the last point in time (which is the same as the furthest point in space) when you think you can accurately place an x at four positions: the front, the back, the top and bottom of the storm?
This is a slight modification and extension to an earlier mini project of finding circular storms. Here the idea is no longer emphasising a simple circle shape- so we can accommodate more awkward/bent/distorted shapes. But what is important is that you can draw an ‘x’ at a minimum of four crucial positions.
I reckon there are quite a few examples of these, so can you find any more storms where the centre of the four points can reach at least the centre of the camera? Below is an example highlighted in the circular storm thread by fellow Stormwatcher lolinda and marked as her favourite 2125. On the left, are unedited screenshots of the storm; on the right, I have drawn the four points and its rough shape on top of the screenshots. I reckon I can do this until 12.90, but then I loose the position of the top left of the storm. When do you think you last see the full shape?
If you have other storms that can be investigated in this way and want to replicate what i did; then I simply took a few screenshots and pasted them quickly into PowerPoint (paint or any other simple picture editor would also work). I then roughly placed ‘x’ where I thought they were most appropriate and put an elliptical shape that roughly followed what I think the shape may be. If an ellipse is not the most ideal you can use a freeform line.
What is the last time you think you can both see and trace the shape?
Which part of the storm disappears first?
As one of the younger members of the UK’s STEREO team, I thought it would be nice to provide a few updates about what a scientist does day-to-day. I am currently coming to the end of my PhD, and am therefore busily writing up a thesis. But, of course, there are a few more interesting things to talk about apart from me sitting in front of a computer!
A lot of my work uses the Heliospheric Imagers on the STEREO spacecraft. In particular, I have been spending my time looking at solar storm case studies, and analysing the overall shape of them. The simplest approximation to the shape of a solar storm is a cylinder. If you observe one end on, you will see a circular shape. I found a perfect example of one that happened in February 2008, using the STEREO Ahead spacecraft (in the pictures below the front half of the circle fades away fast but, a semi circle of the rear edge of a circle can be seen further into space). I then spent some time analysing how this storm grew in size as it travelled away from the Sun.
Previously, scientists have looked at the size of solar storms at different locations in space and have predicted the growth rate. My work was the first time that we have been able to monitor a single solar storm this far away for the Sun.
One problem with my analysis is that solar storms, like hurricanes on Earth, are incredibly variable from one case to another. It would be fantastic if we could find more examples of near-perfect circular storms. We could then build up a better picture. So let me know if you spot anything interesting, and keep up with the great work.