[Gasification] Aviation's role in global warming...9/11 aftermath proves theories on H20 in contrails in dramatic fashion.

Tue Mar 18 21:46:13 CDT 2008

Lack of condensation trails over US immediately after 9/11, 2001 seem to 
increase diurnal temperature range. Also, a net cooling effect can be 
argued. See link and abstract,

http://www.atmos.berkeley.edu/news/cohen_jul2002.article

Travis, D.J., A.M. Carleton, and R.G. Lauritsen, (2004). Regional 
variations in US diurnal temperature range for the 11-14 September 2001 
aircraft groundings: Evidence of jet contrail influence on climate. Journal 
of Climate. 17(5): p. 1123-1134.

Abstract: The grounding of all commercial aircraft within U. S. airspace 
for the 3-day period following the 11 September 2001 terrorist attacks 
provides a unique opportunity to study the potential role of jet aircraft 
contrails in climate. Contrails are most similar to natural cirrus clouds 
due to their high altitude and strong ability to efficiently reduce 
outgoing infrared radiation. However, they typically have a higher albedo 
than cirrus; thus, they are better at reducing the surface receipt of 
incoming solar radiation. These contrail characteristics potentially 
suppress the diurnal temperature range (DTR) when contrail coverage is both 
widespread and relatively long lasting over a specific region. During the 
11-14 September 2001 grounding period natural clouds and contrails were 
noticeably absent on high-resolution satellite imagery across the regions 
that typically receive abundant contrail coverage. A previous analysis of 
temperature data for the grounding period reported an anomalous increase in 
the U.S.-averaged, 3-day DTR value. Here, the spatial variation of the DTR 
anomalies as well as the separate contributions from the maximum and 
minimum temperature departures are analyzed. These analyses are undertaken 
to better evaluate the role of jet contrail absence and synoptic weather 
patterns during the grounding period on the DTR anomalies.

It is shown that the largest DTR increases occurred in regions where 
contrail coverage is typically most prevalent during the fall season (from 
satellite-based contrail observations for the 1977-79 and 2000-01 periods). 
These DTR increases occurred even in those areas reporting positive 
departures of tropospheric humidity, which may reduce DTR, during the 
grounding period. Also, there was an asymmetric departure from the normal 
maximum and minimum temperatures suggesting that daytime temperatures 
responded more to contrail absence than did nighttime temperatures, which 
responded more to synoptic conditions. The application of a statistical 
model that "retro-predicts" contrail-favored areas (CFAs) on the basis of 
upper-tropospheric meteorological conditions existing during the grounding 
period, supports the role of contrail absence in the surface temperature 
anomalies; especially for the western United States. Along with previous 
studies comparing surface climate data at stations beneath major flight 
paths with those farther away, the regionalization of the DTR anomalies 
during the September 2001 "control" period implies that contrails have been 
helping to decrease DTR in areas where they are most abundant, at least 
during the early fall season.

At 07:05 PM 3/18/2008, you wrote:
>Ah Frank,
>
>
>Just in case you haven't noticed, CO2 doesn't make contrails - it's the
>water vapor in the jet exhaust that makes the contrails, and everyone knows
>that water vapor is a stronger greenhouse gas than CO2.    Contrails are
>nothing more than the water vapor from the exhaust that is condensing to for
>a type of cloud.
>
>
>What's going on is that everyday, all day long, jet's go back and forth
>laying down a blanket of water vapor that may not be letting as much heat
>out at night.
>
>In this case, it not CO2, but water vapor, that is the active principle.
>
>Greg H.
>
>
>----- Original Message -----
>From: "Katahdin Energy Works" <KatahdinEnergyWorks at verizon.net>
>To: "'Discussion of biomass pyrolysis and gasification'"
><gasification at listserv.repp.org>
>Sent: Tuesday, March 18, 2008 13:46
>Subject: Re: [Gasification] Aviation's role in global warming...9/11
>aftermath proves theories on H20 in contrails in dramatic fashion.
>
>
> > "Station Crew Notes Absence of American Air Traffic in Wake of Terrorist
> > Attacks
> > By Todd Halvorson
> > Cape Canaveral Bureau Chief
> > posted: 01:26 pm ET
> > 14 September 2001
> > CAPE CANAVERAL, Fla. The International Space Stations crew spied yet more
> > evidence Friday of the aftermath of this weeks terrorists attacks on
> > America: the lack of air traffic over the continental United States.
> >
> > Three days after suicide airplane hijackers toppled the World Trade Center
> > in New York and slammed into the Pentagon in Washington, D.C., the station
> > crew noted an obvious absence of airborne jetliners from their perch 240
> > miles (384 kilometers) above Earth.
> >
> > "Ill tell you one thing that's really strange: Normally when we go over
> > the
> > U.S., the sky is like a spider web of contrails," U.S. astronaut and
> > outpost
> > commander Frank Culbertson told flight controllers at NASAs Mission
> > Control
> > Center in Houston.
> >
> > "And now the sky is just about completely empty. There are no contrails in
> > the sky," he added. "Its very, very weird."
> >
> > "I hadn't thought of that perspective," fellow astronaut Cady Coleman
> > replied"
> >
> > ....neither did IPCC; but a subsequent research study revealed a 1 degree
> > C.
> > change in temperature as, once again; normal cooling of the land masses
> > beneath these corridors took place--- and as every school child knows;
> > that
> > equals the rise in global warming measured over the past fifty years.
> >
> > ...I rest my case on the relatively insignificant role CO2 plays in
> > G.Warming.!
> >
> > Frank J. Heller, MPA
> > KATAHDIN ENERGY WORKS
> > 12 Belmont St.
> > Brunswick, ME 04011-3004
> > 207.729.6090
> > http://mysite.verizon.net/fjheller/
> >
>
>
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