Still trying to get my head round this, although I suppose it's logical enough. "Bombing raids by Allied forces during the Second World War were so powerful they sent shockwaves through Earth's atmosphere to the edge of space, researchers have found. The huge bombs dropped by Allied planes on European cities were big enough to weaken the electrified upper atmosphere – the ionosphere – above the UK, 1000km away. Researchers studying records from the time found each raid released the energy of at least 300 lightning strikes. 'The impact of these bombs way up in the Earth's atmosphere has never been realised until now, said Chris Scott, Professor of Space and Atmospheric Physics at the University of Reading. 'It is astonishing to see how the ripples caused by man-made explosions can affect the edge of space.' The discovery was made after researchers analyzed daily records from the Radio Research Station at Ditton Park near Slough, where routine measurements of the ionosphere were taken from 1933 to 1996, in what is the 'the longest continuous set of ionospheric measurements in the world' according to the study published in the journal Annales Geophysicae. 'Each raid released the energy of at least 300 lightning strikes,' said Scott. 'The sheer power involved has allowed us to quantify how events on the Earth's surface can also affect the ionosphere.' The researchers decided to focus on major bombing raids of German cities by Allied forces and the Royal Air Force between 1943 and 1945, rather than the 'London Blitz' earlier in the war. This is because the blitz was ongoing from September 1940 to May 1941, which means the data would be harder to separate from other seasonal changes due to the sun that might affect the ionosphere. Researchers studied the ionosphere response records around the time of 152 large Allied air raids in Europe and found the electron concentration significantly decreased due to the shockwaves caused by the bombs detonating near the Earth's surface." www.dailymail.co.uk/sciencetech/article-6208203/Allied-bombing-raids-Second-World-War-powerful-sent-shockwaves-edge-space.html
The problem is it wasn't a single detonation (like in Hiroshima) but numerous sequential detonation because obviously, all the plans didn't drop their bombs simultaneously. Over Hamburg (July, 27) it was a full load of bombs every about 5 seconds (700 bombers in one hour). Over Dresden, the first raid dropped a full load of bombs every half a second (the "fastest" raid ever), but the second only one every three seconds. Although obviously some detonations randomly cumulated, most didn't so the theory of detonations "so powerful they sent shockwaves ... to the edge of space" is false. Additionally, up to 40 percent of the bombs were incendiary bombs which didn't even detonate in any meaningful way. The detonation velocity of TNT is about 7 km/s, so the separation between individual shockwaves was about 35 km (Hamburg). The lowest separation achieved was 4.5 km (the first raid on Dresden). btw "300 lighting bolts" is about 370 tons of TNT, a very low number (Hamburg = 22,580 tons of bombs, Dresden = 9,000 tons) - it seems someone over there has a problem with elementary mathematics.
There was a pretty impressive raid on an airfield in France the details of which were probably not recorded. My uncle told me about it. I have mentioned the story before on this board so if it sounds like a repeat ... Seams his squadron was at the rear of the bomber stream headed for Germany one day. The weather closed in and obscured all the primary and secondary targets. His pilot was the lead pilot for his squadron and asked him (he was the navigator) to find a target of opportunity. Seems there was this airbase in France that they often got routed over. Never saw much if anything in the way of fighter activity from it but apparently they had some really good AA gunners. So he chose it as the target of opportunity. They had turned around and were headed for the target when the pilot asked him if he was sure he knew where he was going. My uncle (a bit irritated with the question) said "yes, why". The pilot replied "Because all of 8th Air Force is following us". As far as he knew they didn't receive any more or at least any significant AA fire from that airbase at least during his tour. Not sure how many planes were flying that day but it must have been more than they would expect to hit a minor air base.
The important question is whether or not there was any permanent or long term disruption of the ionosphere!
What do you mean by "long term"? Likely there were effect that we could measure today for days and possibly a few years afterwards. Decades would be a possibility but I wouldn't expect to see any effects after a few (i.e. by today). Consider that the ban on chlorofluorocarbons seems to have pretty much healed their impact and the shock waves don't seem to have had as much impact indeed it seems to have been more localized. I would like to see a scientific report on it especially if it compared the impact of above ground nuclear blasts to those listed.
Used to have an interest in the ionosphere in my radio ham days, but never really got heavily into it. Ionosphere - Wikipedia
I suppose it's possible firestorms generated so much energy they were able to disrupt the ionosphere. This could be tested by comparing the results with large forests fires, which should be able to disrupt the ionosphere in a similar manner. According to FEMA 10,000 of TNT generates 0.5 psi of overpressure at 1700 ft. It's about 3 percent above atmospheric pressure, barely noticeable by humans. A barely noticeable blastwave is not going to reach the ionosphere and disrupt it. They say "bombing raids by Allied forces during the Second World War were so powerful they sent shockwaves through Earth's atmosphere" as if all bombs exploded at the same time. But it's not true in reality a load of bombs, up to several tens of TNT, exploded every few seconds. Such an explosion dissipates almost completely at 2000 ft. The ionosphere begins at 45 miles.
There are at least 2 unproven assumptions buried in that sentence and the article indicates that there is at least some evidence that both are wrong.
The ionosphere begins at 45 miles. About 37 miles according to that link. That's roughly 195,360 feet (1 mile=5280 feet x37) I would argue about a blast wave not bring able to reach the ionosphere- "A detonation wave is essentially a shock supported by a trailing exothermic reaction. It involves a wave travelling through a highly combustible or chemically unstable medium, such as an oxygen-methane mixture or a high explosive. The chemical reaction of the medium occurs following the shock wave, and the chemical energy of the reaction drives the wave forward.A detonation wave follows slightly different rules from an ordinary shock since it is driven by the chemical reaction occurring behind the shock wavefront. In the simplest theory for detonations, an unsupported, self-propagating detonation wave proceeds at the Chapman-Jouguet flow velocity. A detonation will also cause a shock of type 1, above to propagate into the surrounding air due to the overpressure induced by the explosion.When a shock wave is created by high explosives such as TNT (which has a detonation velocity of 6,900 m/s), it will always travel at high, supersonic velocity from its point of origin." Shock wave - Wikipedia
This is a FEMA advisory on VBIEDs. As can be seen, a 1000lbs of TNT detonation ceases to exist past 700 feet. It becomes basically a gust of wind. At 2000 ft it's not even noticeable by people.
There's a big difference between "ceases to exist" and "noticeable by people". Most people can't detect changes in atmospheric pressure but they certainly exist and have significant impact on the weather. Likewise you may not even feel a Tsunami if you encounter one at sea. On the beach however ...
With all due respect. There is no practical difference between those two terms. Even something barely noticeable by people at 700 ft is not going to travel another 60,000 ft and disturb anything as the pressure decreases very rapidly, with the cube of the distance. In this case, it gets ten times weaker every roughly about 500 ft. And a tsunami is hardly comparable with a 1000lb of TNT. Tsunamis are 10-30 megatons of TNT (like that released by the 2004 Indian Ocean earthquake = 26 megatons). Additionally, detonations and tsunami are two different physical phenomena governed by two different sets of equations. Both can't be compared in any meaningful way, the main reason is air is highly compressible, water is incompressible. And btw they were no beaches between Germans cities and the ionosphere.
Sorry no. Again if you are at sea and below decks you won't even know if you encounter e tsunami. If your boat is in a marina or anchored just off shore it will be pretty obvious. The boat at sea can be much closer to the point of origin as well. The point being you basic assumption that "barely noticeable" = "ceases to exist" is flawed and irredeemably so. Now it is the daily mail so we don't have any detailed scientific reports yet but the implication is that they exist and there is real data that shows you are wrong in this particular case as well. So far you've done very little to support your position and that's being charitable.
I didn't mention and don't deny that "if you are at sea and below decks you won't even know if you encounter tsunami" so it's a pointless argument. I didn't assume that "barely noticeable" = "ceases to exist" so it's another pointless argument. I only noticed that in this circumstances it didn't matter because: "something barely noticeable by people at 700 ft is not going to travel 60,000 ft and disturb anything as the pressure decreases very rapidly, with the cube of the distance. In this case, it gets ten times weaker every roughly about 500 ft." I expressly used above "barely noticeable" and it means 0.5psi of overpressure, i.e. 3 percent above normal pressure. Again, 3 percent overpressure is not going to travel 60,000 ft because every 500 ft it gets ten times weaker. On the other hand, a wave in water would travel said 60,000 ft almost without energy loss (because water is incompressible). Similarly the megatons generated at the source of a tsunami arrive at the beach almost undisturbed. The waves are initially very flat and invisible but wave shoaling compresses them and make them deadly.
And for example, using equations found in this paper (table 1) it can be calculated that 1 ton of TNT generates overpressure: at 10m = 1000 times above atmospheric, 100m = 10 times above, 1000m = 0.1 percent above, 10km = 0.06 percent, so at 10km the overpressure is basically impossible to detect by any method known to man. In comparison, it is possible to create overpressure 10 percent above atmospheric pressure by simply using your mouth.
Here's the abstract of the original article without the paper's hyperbole. "The analysis was repeated for a range of thresholds in both time of bombing before the (noon) ionospheric measurement and tonnage of bombs dropped per raid. It was found that significant ( ∼ 2–3σ) deviations from the mean occurred for events occurring between approximately 3 and 7h ahead of the noon ionospheric measurements and for raids using a minimum of between 100 and 800t of high explosives. The most significant ionospheric response (2.99σ) occurred for 20 raids up to 5h before the ionospheric measurement, each with a minimum of 300t of explosives. To ensure that the observed ionospheric response cannot be attributable to space-weather sources, the analysis was restricted to those events for which the geomagnetic Ap index was less than 48 (Kp < 5). Digitisation of the early ionospheric data would enable the investigation into the response of additional ionospheric parameters (sporadic E, E and F1 layer heights and peak concentrations). One metric ton of TNT has an explosive energy of 4.184×109J, which is of the same order of energy as a cloud to ground lightning stroke." ANGEO - The ionospheric response over the UK to major bombing raids during World War II At the end, it does mention that "further investigation, using less extreme examples, is required to determine the minimum explosive energy required to generate a detectable ionospheric response."
The article, in it's entirety, can be found here: https://www.ann-geophys-discuss.net/angeo-2018-44/angeo-2018-44-typeset_manuscript-version3.pdf