Noctilucent Clouds Likely Caused By Shuttle Launches 132
icebike writes "In our recent discussion of the phenomenon of noctilucent clouds, there was some suggestions that these might be the product of global warming due to moisture being lofted high into the atmosphere. It now appears that these clouds are simply the product of Shuttle launches. In a story about the Tunguska blast, Science News says: 'Each launch of a space shuttle, which burns a combination of liquid hydrogen and liquid oxygen as fuel, pumps about 300 metric tons of water vapor into the atmosphere at altitudes between 100 and 115 kilometers. Soon after the January 16, 2003, launch of the shuttle Columbia, a liftoff that took place just after the height of summer in the Southern Hemisphere, noctilucent clouds appeared over Antarctica. Similarly, a widespread display of the night-shining clouds showed up over Alaska two days after the shuttle Endeavour blasted off on August 8, 2007. Previous studies show that in both instances those clouds included material from the shuttle plumes.' So, man-made after all?"
Um, first observed in 1887 - well before shuttle (Score:5, Informative)
The previous Slashdot thread included the tidbit that the first noctilucent clouds mentioned in recorded history were in 1887 (also noted here [wikipedia.org]). So unless someone was using hydrogen-oxygen rocketry almost a full century before the first shuttle launch, it would seem that they are not purely anthropogenic.
Cheers,
Re:Carbon credits for shuttle launches? (Score:3, Informative)
Since the water vapor brought into the atmosphere in high altitudes likely increases global warming (water vapor is a more effective greenhouse gas than CO2), I don't think they could get carbon credits.
This is *OLD* news... see APOD! (Score:4, Informative)
From June, 2003: .... note the last sentence.
http://apod.nasa.gov/apod/ap030615.html [nasa.gov]
6 years.
Sometimes it takes main stream media a while to catch on.
Note that this APOD entry has further links to US Navy research on the topic.
Re:Um, first observed in 1887 - well before shuttl (Score:5, Informative)
Noctilucent clouds occur over a very small altitude range (about 82-84 km) Observations of the same cloud from different locations can be used to find the height by triangulation. ISTR that the 1887 observation did this and that it is therefore a genuine observation of NLC.
The question of whether there were no NLC before this date was a contentious one last time I asked. Some make the argument that NLC are very distinctive and that if they were there we would have records going back to the Viking era, as we do with the Aurora Borealis. Others, however, argue that NLC look sufficiently like other clouds and are sufficiently unremarkable to the casual observer that it is not surprising that there are no descriptions prior to 1887. (Remember that the idea that it is worth naming and describing clouds only really goes back to Luke Howard in the early 1800s.)
Re:Noctilucent clouds have been observed in Europe (Score:2, Informative)
There are 3 requirements for these clouds to form:
1. Dust in the mesosphere to seed the accumulations
2. Moisture in the mesosphere
3. Temperatures less than about 150K
There isn't a lot of either dust or water in this part of the atmosphere, and things like volcanic eruptions, and shuttle launches are one mechanism by which large quantities of both can be transported to this layer of the atmosphere, which is what TFA is saying.
The clouds themselves form when the temperature in this layer is low, and the lowest temperatures in this region occur in summer, counterintuitively. This is of course when temperatures are highest in the lower atmosphere.
So, the cooling you refer to hasn't got any established relationship with the "scam" of global warming, and if it did, it wouldn't support your argument.
Re:Um, first observed in 1887 - well before shuttl (Score:2, Informative)
> photography, in much the same way Color was invented in the 50s.
You're off by a couple of decades. The world turned color starting in the thirties. Although, it was pretty grainy color for a while.
Cognitive filtering (Score:3, Informative)
Here's what I find interesting: the bulk of the 'data' behind anthropogenic global warming points to a rise in temps THIS century of a small handful of degrees. The concern is over the consequences of a further rise of, again, a small handful of degrees.
Now, drag out all the charts, graphs, and politically-motivated reports you want, for and against; the only actual modern large-scale experiment that gives us any proof regarding human impact on temperature was the week after 9/11.
The complete lack of aircraft over the US had a SIGNIFICANT effect on high and low temperatures immediately.
Couple that with this current evidence that a single shuttle launch can apparently impact cloud formation over the Antarctic, and I'd say that's a far-more-tangible red flag than the supposed connections made over CO2 or other 'global warming' gases.
So why isn't there a significant, sustained effort to minimize air travel?
Re:Um, first observed in 1887 - well before shuttl (Score:2, Informative)
Thank you, Calvin's dad.
Re:Causing, or contributing? (Score:3, Informative)
I can't read the article due to Slashdot effect, but if shuttle launches are contributing to or causing (big difference there!) the formation of the noctilucent clouds then there should be a correlation to check for.
They did and there was - http://www.nrl.navy.mil/pressRelease.php?Y=2003&R=35-03r [navy.mil]