Posts Tagged kelvin-helmhotz
Well, hello from Storm Angus ravaged Wales!
Kind of storm ravaged. Okay…not at all, just the tail end. We didn’t get this all half as bad as the south of England, if you wish to, you can read about the main bits in the Daily Telegraph.
Cue the normal film (courtesy of YouTube on this occasion) on the evening news of people who should know an awful lot better canoeing in the street, standing perilously close to waves crashing onto beaches, generally being a teeny bit dull or driving into water that is far too deep.
Honestly, if I knew that Newhaven and Brighton and similar areas were going to get this much coverage in the years after I moved to Wales, I wouldn’t have bothered coming! Only kidding. Still, at least I stayed relatively dry. The wind was perishing cold though, that was what bothered me the most as I don’t have an awful lot of meat on me. This is due to get less after Christmas too as I will be embarking on a proper 12 week training regime to do a further sportive bike ride of 100 km (60 miles) in aid of charity. I was looking at the handy downloadable training timetable and I am struggling to think of routes that fulfil the length of time or distance needed and also go in a loop to assist me in not transporting the bike around the county in a car that is too small for it. I’m sure it’ll be fine.
However, let us not be bothered by my good deeds. You read this for my wit and pictures don’t you? I like to think so, but I could be having a one-way conversation with the vast internet. So let us begin.
Iridescence. Difficult to spell, even more difficult to spot. More difficult to photograph than both of those things. I think I have posted images on here with some “mother of pearl” effects in some winter clouds but these are not to be confused with the proper nacreous or polar stratospheric clouds.
In this instance, you have to look very carefully at the tips of the dead clematis flowerhead I took a picture of a while back…
I never noticed the fact there was some iridescence in this image when I took it to be honest but looking at Mr Wikipedia…thanks be to Wikipedia…it says that the effect is generally created by microstructures that interfere with light, which figures as these flowers are very intricate and the flash fired in this image.
On to a more familiar subject, the sky, but a more unusual effect in the clouds than usual. You may remember a while back that I pointed out some oh-so-catchy Kelvin-Helmholtz instability in clouds at sunset that caused what look like cresting waves? In a nutshell, it’s the interaction of two fluids of varying density such as the wind creating a wave on water (yes, air can indeed be construed as a fluid in science). It seems that the effect can go full circle (pun intended) and create what essentially looks like a corkscrew.
Pretty cool, huh? I have only seen this the once and I can only find a few images on the internet that are similar, so you never know, I may have stumbled on a new cloud type! I will name it “the screw-mulus”. Or I could be over-thinking things….yes, the latter.
Now, moving away from science but to return to it in a little while, some sunset pictures I took just because and in the order of this post heading towards the end of the day in subject matter. Not that many sunset images at all this year, seems we have way too much low cloud now, so there will be fewer and fewer of these images of feathery loveliness…
This next one is an unusual one as there are quite a few “straight” lines in the cloud. I say straight with a little bit of a nudge as they aren’t ruler straight, but in nature, you very rarely find anything too straight, so when you see it, it’s usually due to interaction with something unexpected…in this instance, I suspect the contrail on the right at a similar angle has something to do with it.
Back to science! Rays. In particular, crepuscular rays. I have posted many images on here of these rays but now I present to you a rarer image of….anti-crepuscular rays. It is pretty much the same thing but you see these opposite the sun, not around it, behind a cloud or such like. The rays are caused by the interaction of the light with an object out of your line of sight due to the curvature of the Earth, so as the sun dipped just below the horizon here, a little cloud got in the way, casting this shadow…
Apologies for the dark image, I had to fiddle the contrast to enhance the rays somewhat. However, talking of dark brings me nicely to my last image for this post, a nightscape. I don’t often do these, as it’s not an area I have a great deal of skill in, but I try. I took this of the refinery and fuel storage areas around Pembroke (on the left) and Milford Haven (on the right) from Pembroke Dock.
I even managed to catch a little starlight in the image which was not my intention, but it adds a little depth to the inky black bits. I might try this further in the future, but I find them a little boring being so dark and having a not so well suited camera for this kind of stuff. We shall see.
Well, there you have it for another post. Before I go, just a couple of things…I need one more follower to reach 50 so if you have a friend or relative who can stand my infrequent babble, tell them to pop to my site on a PC and click the “Follow Me” link at the bottom right. Thanks!
Also, I have changed a few bits on the site such as the background banner and post text. Hard to read, too small, too large? Constructive criticism is very much welcomed!
Cheers in advance and see you soon.
I return. Been a bit busy of late and with the weather getting better by the day, they has been quite a lot of riding of my new bike to be done. Also, when I had it serviced recently I opted to fit gel inner-tubes to protect against punctures, so I am now more confident riding the paths around here that seem to be strewn with thorns for some reason.
Also, my work colleagues have decided that being single is a source of lunch hour amusement for them and have put me on a site called Plenty of Fish…probably to take the mickey even further, but it’s quite time-consuming! I was also persuaded to attend a singles night locally the other day; little did I know that I would be the only person there. No, not the only man, the only person. I even got let down by people who promised to come with me! The barmaid was very apologetic, but it was super embarrassing…
Anyway, what a difference an hour makes in South West Wales weather? When I got up the wind was blowing and the rain was horizontal but now, I’m squinting against the sun as I type! Mind you, there has been a lot more of interest in “space weather” of late as you may have seen on the news lately? If not, there was a “supermoon” (which saw some amazingly low tides around the beaches near here), the partial eclipse and a sighting of the Northern Lights over Pembrokeshire. Should you want to see the local cover, please refer to the local paper…
Read about the eclipse over Pembrokeshire here
See some pretty awesome (although not as you see them in Norway, unfortunately) Aurora pictures here
Anyway, I shall start popping my own pictures on now! As I said, this is a bit of a random collection of mainly weather, as it appears that my travels were somewhat curtailed and these were more local wanderings. Firstly, a spider that caught my eye in the garden, wrapping up his next big meal it appears..
That is a pretty funky spider tattoo down his back, isn’t it?! I fully admit that I am no fan of spiders, but will concede that they are amazing little creatures. I am quite thankful that I live in a country that just has small ones though, not like the tropics. Eeek!
Moving on to the skies, as I quite often do, a nice dusk that I took a few pictures of. I have included these as I noticed on review of the images that there was a little aberration in the latter picture…not sure whether I noticed this at the time though…
In the latter image below, just above and to the left of the trees, you will notice a line of Kelvin Helmholtz instability. Now, I don’t know whether this is some optical illusion or something as the earlier pictures shows some “waves” in the high cloud. I can’t say for sure, but I’d like to think I caught the creation of the waves over time 🙂
Next, a common occurrence over Pembrokeshire, some mild asperatus. This is the only place I have ever seen the regular appearance of this cloud, that is similar in age to me. In that, I mean that it wasn’t really officially recognised as a type of cloud until 30 or so years ago; I’m sure it has been around for donkeys years. In the textbooks and such, this is a precursor to rain or is on the rear edge of a front that was just carrying rain (this I can testify to). So, if you see clouds like this, get a coat….
As the sky got a bit dimmer, there was a nice watery orange sunset so I snapped a quick image of that with a little of the asperatus in…
A few days later, things had turned a bit squally again. This again seems to be a theme here, there are times where we have weeks of squally heavy showers and because of the position of the house and the hills in the distance, we get a pretty good grandstand view. In the first instance there was this little cell struggling to make itself into an anvil shape over the estuary to our north, bless it…
Alas, wind blew this little cell apart and it died away to be replaced by three of four layers of “scud” which were whipping along in the wind at quite amazing speeds. I took a picture of these as they passed, as the colours and contrasts of the different levels were pretty cool, I thought…
For every cell that falls apart there are a few that succeed in dropping their rain. This one and the following picture are from a day where things were a little less “lumpy” so they are much more streamlined and pleasing to the eye, even though in looking at them you would have got wet! From this angle, you can see what I mean in me getting a good view as the weather moves from left to right (from the Irish Sea inland)…
And to finish, a rainbow! Everyone loves a rainbow. No particular structure to this one as this was a fleeting one that passed by in the clouds as the rain flew around in the air. Again, this is something which happens quite a lot in the Spring around here, very pretty…
Well, there we have it, I hope that the fact that the sun is (trying to come) out and the flowers are blooming has cheered you up and these picture may have raised a grin too. Don’t forget the clocks go forward this weekend too!
Next week, I see that I was out and about when there was fantastic display of cirrus “mares tails”, basically windblown cirrus clouds very high up in the atmosphere that also seem to show themselves in advance of heavy weather which I also manage to capture, so I shall be posting those images. I have others from my wanders that week too so if you are good, I might post some more moving water…
Well, that’s the lot for this post, cheers for dropping in and taking a peek, see you soon. I will also update you on any decent single life news in the next entry 🙂
Hello you lot!
Appreciate the patience here, thanks for waiting for my post without running off. Unlike some that post openly on Facebook or something that they are off on holiday so someone can come round and rob their house (it has happened, Google it if you don’t believe me!), I thought it best to do this after I returned. I spent a very nice holiday in Bruges and, in time, with be posting the images on here; remember, they’re all posted in retrospect!
For now, I am posting a few more images of weird things in the sky. Some you have seen before, some you have not. I’m sorry if this is samey, but I can’t help but love the weather…I even managed to get some pictures of an awesome hail core from my hotel window when I was away!
In the first instance, there’s a familiar beast, a very pleasant sunset with a nice hint of pink for a twist. Don’t get that pink hue up so high too often so it was nice to see again.
However, whilst I was there, my eye caught on some “cuckoo-spit” and I thought I would include that too just for interest and the fact that the macro mode on the camera is not very oft used! I looked this up and found the name of an insect that creates this and can’t say I have ever heard of it. This is apparently the protective covering for a froghopper nymph known as a “spittlebug”; yup, I had never heard of it either. I knew that it was a protective coating for something though, apparently created by the nymph feeding on the sap of whichever plant it is on which causes no real damage. Everyone’s a winner…
Next up is another better view of some Kelvin–Helmholtz instability (on the right hand side in the middle of the image, looks very much like a breaking wave side on) that I saw whilst out on my bike. Alas the background is a similar colour so, sorry, you may have to squint a little to see it!
Moving on to things you may not have seen and an image I have also passed on to WeatherNet for their competiton (will keep you informed), is a contrail shadow from a perfect conjunction between the old contrail and the setting sun with just enough darkness to make it stand out quite well. Quite a number of coincidences there, but pretty striking I thought.
Last, but not least, is something I haven’t seen all that often, so hopefully you haven’t too which is some “jellyfish” clouds. On a very small scale and nothing like the ones found on the internet in more far-flung places than Pembrokeshire…
Referring to my friends in Wikipedia again to explain this, the cause is thus “particles of ice found in high altitude clouds of the cirrus family, convective clouds and some mid-level clouds are mixed with supercooled droplets of water; they are associated with icing conditions that occur when an aircraft flies through the clouds and serve as a catalysis to the formation of ice crystals” which then fall as these fronds from the cloud.
I guess this means that if you are in a plane and you fly through these, you want to turn the heaters on?! Mind you, at sunset they looked pretty so I thought it worthwhile to pass the sighting on.
Well, that’s the lot for the time being so hope you liked it. More in the next few days. Back on the boat sailing this weekend too so will keep you up to date with that too.
See you soon!
I’m back again for another instalment of my usually skyward-gazing photographs from the skies over a quiet area of Pembrokeshire.
Before I forget, as I will probably, I will mention that I am once again entering the WeatherNet weather photography competition this year. I won a prize last year of, I think, £20 which is no kings ransom I admit, but it was nice to get some input. Mind you, I didn’t think the image I sent was particularly deserving but there we are. This year, I have sent some very nice ones and, whilst I’m no storm chasing pro, I think there’s some pretty awesome cloudscapes. I posted some on here a while back actually….in February this year; take a look. I seem to recall I entitled it the best storm cloud ever. How imaginative.
Anyway, back to the current pictures. The first couple I am not too sure about but I think there was some mild disturbance in the clouds called Kelvin-Helmholtz instability. Now, I never did get science at school so let me introduce Mr Wik E. Pedia with his explanation (all credit to the well-known online encyclopedia);
The Kelvin–Helmholtz instability can occur when there is velocity shear in a single continuous fluid, or where there is a velocity difference across the interface between two fluids. An example is wind blowing over water, the instability manifests in waves on the water surface. More generally, clouds, the ocean, Saturn’s bands, Jupiter’s Red Spot and the Sun’s corona show this instability.
Still confused? Me too. Basically, in this instance, it is waves and undulations in the clouds…
This picture may show things a little more clearly. When people say that air should be treated as a liquid, this is where it all makes a bit more sense!
The next phenomena was a little more “normal” per se but quite nice nonetheless. Just a normal squall mixed with some blue sky and cirrus that I regularly watch and take pictures of to begin with, but I noticed that as I was watching, there was a distinct little “cell” (don’t know if I should refer to it as that to be honest, but for the purposes of the blog I will) off to the left of the frame…
Surprisingly, you could actually see this “cell” moving in a spiral manner. It was admittedly happening veeeeeeeeeeery slowly, but you can actually see in this frame that it looked a little like foamy water in a bath plug. Not quite rotating but nearly….
Pretty much bang overhead now and there is a distinct oval/circle formation here with lumpy cloud in the middle which was probably very mild mammatus, having seen this kind of thing on a larger scale on YouTube…
No rain came down from this over us, but I like to think it may have broken somewhere further away. Once it had moved off the light got better and most of the details were lost for the purpose of photography, which was a shame.
Back to my easy wins then! I love a good sunset and I have caught a good few nice ones of late, as well as some arcs and sundogs that will feature shortly. This one is just down the road in Sardis. Truth be told, I was in the wrong place to catch it properly so I had to make do with the less that ideal foreground. Mind you, I don’t think it’s all that bad…
A few days later, the air was still pretty clear and there were hardly any contrails around, so there was a rare full frame cirrus cloud that I took a snap of. Remember, this is how it appeared at the time, none of your digital manipulation here!
Well, I hope that you found this a good distraction for a few minutes…I enjoyed taking the pictures anyway. I will keep you informed regards the competition but the closing date is late September so you will see another few posts before then.
That reminds me, I really must send the remainder of my shots! See you all soon, thanks for dropping in.