4 ms·

> "The week following 9/11 was dramatically different. NASA recorded the change in daily temperature range. Less significantly, we had crystal clear skys where

> "The week following 9/11 was dramatically different. NASA recorded the change in daily temperature range. Less significantly, we had crystal clear skys where I live - for a week!" Do you have links for this?

wmf 7y ago
https://web.archive.org/web/20160411094048/http://www.atmos.washington.edu/~rennert/etc/courses/pcc587/ref/Travis-etal2002_Nature.pdf https://web.archive.org/web/20160411094048/http://www.atmos.... https://www.nature.com/news/2008/081231/full/news.2008.1335.html https://www.nature.com/news/2008/081231/full/news.2008.1335....
- andreasley 7y ago
  The second link actually states the opposite: "A new analysis now claims that altered US temperature patterns during the three flight-free days can be explained by natural variations in cloud cover, rather than the absence of planes."
  - mehrdadn 7y ago
    Just imagine how this will get magnified and drive the world nuts when half the things we try to do to tackle climate change end up being plausibly explainable by natural variation. It's already a hard enough problem to solve without natural variance being thrown into the mix.
  - phkahler 7y ago
    But that's not conclusive either. There is this: The research by Hong and his colleagues, published in Geophysical Research Letters, follows other studies arguing that the September 2001 temperature variations can be explained by the clear, dry weather on the crucial days4, and that climate-modelling results do not support the contrail effects claimed by Travis's group5. I contend the clear dry weather was a consequence of the lack of planes. It sounds the one of the original authors does too. All I know is the weather here was beautiful. And very uncharacteristically so. Unfortunately nobody is going to repeat the experiment by grounding the entire fleet for 3 days just to test it.
AprilArcus 7y ago
Minnis, Patrick, J. Kirk Ayers, Rabindra Palikonda, and Dung Phan, 2004. "Contrails, Cirrus Trends, and Climate". Journal of Climate Vol. 17, No 8, pp. 1671-1685, April 15, 2004 doi:10.1175/1520-0442(2004)017<1671:cctac>2.0.co;2 https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%282004%29017%3C1671%3ACCTAC%3E2.0.CO%3B2 https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%28200...
ebrewste 7y ago
I remember hearing about this at the time. Some links I just looked up: https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.pdf https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.p... https://www.pbs.org/wgbh/nova/article/contrail-effect/ https://www.pbs.org/wgbh/nova/article/contrail-effect/
blunte 7y ago
I lived in Dallas at the time. It was eerie having a few days of No air traffic; and indeed the air was much less visible (so presumably cleaner).

wmf 7y ago

https://web.archive.org/web/20160411094048/http://www.atmos.washington.edu/~rennert/etc/courses/pcc587/ref/Travis-etal2002_Nature.pdf https://web.archive.org/web/20160411094048/http://www.atmos.... https://www.nature.com/news/2008/081231/full/news.2008.1335.html https://www.nature.com/news/2008/081231/full/news.2008.1335....

andreasley 7y ago
The second link actually states the opposite: "A new analysis now claims that altered US temperature patterns during the three flight-free days can be explained by natural variations in cloud cover, rather than the absence of planes."
- mehrdadn 7y ago
  Just imagine how this will get magnified and drive the world nuts when half the things we try to do to tackle climate change end up being plausibly explainable by natural variation. It's already a hard enough problem to solve without natural variance being thrown into the mix.
- phkahler 7y ago
  But that's not conclusive either. There is this: The research by Hong and his colleagues, published in Geophysical Research Letters, follows other studies arguing that the September 2001 temperature variations can be explained by the clear, dry weather on the crucial days4, and that climate-modelling results do not support the contrail effects claimed by Travis's group5. I contend the clear dry weather was a consequence of the lack of planes. It sounds the one of the original authors does too. All I know is the weather here was beautiful. And very uncharacteristically so. Unfortunately nobody is going to repeat the experiment by grounding the entire fleet for 3 days just to test it.

AprilArcus 7y ago

Minnis, Patrick, J. Kirk Ayers, Rabindra Palikonda, and Dung Phan, 2004. "Contrails, Cirrus Trends, and Climate". Journal of Climate Vol. 17, No 8, pp. 1671-1685, April 15, 2004 doi:10.1175/1520-0442(2004)017<1671:cctac>2.0.co;2 https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%282004%29017%3C1671%3ACCTAC%3E2.0.CO%3B2 https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%28200...

ebrewste 7y ago

I remember hearing about this at the time. Some links I just looked up: https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.pdf https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.p... https://www.pbs.org/wgbh/nova/article/contrail-effect/ https://www.pbs.org/wgbh/nova/article/contrail-effect/

blunte 7y ago

I lived in Dallas at the time. It was eerie having a few days of No air traffic; and indeed the air was much less visible (so presumably cleaner).