Re: Ma scusate...
Inviato da padma il 22/1/2007 14:51:35
Alcuni estratti dell'articolo di Minnis, che rappresenta diciamo la comunità scientifica ufficiale riguardo alle scie (già si vedono alcune notizie interessanti):
Contrails occupy a fairly special niche in atmospheric thermodynamics because they form and produce ice clouds at ambient relative humidities that are less than those required for most natural cirrus cloud formation.
The largest concentrated increases
occurred over the northern Pacific and Atlantic
and roughly correspond to the major air traffic routes
reflected in the ECON distribution..
Contrails often advect hundreds of
kilometers as they develop.
The frequency of clear-sky observations was also
computed for the land air traffic regions. Over the United
States and WASIA, the frequency of clear skies
changed by 21.3% and 1.8% decade21, respectively.
Over EUR and WEUR, clear-sky frequency decreased
by 0.6% and 0.7% decade21, respectively.
The seasonal variations in CC (cirrus coverage, nota mia) and CCI (total cirrus coverage, nota mia) trends over the United States (Fig. 4a) are generally consistent with the seasonal variations of contrail occurrence frequency
Thus, persistent
contrails are likely to form if Rh . 40% and T,2398C
as measured from radiosondes, while cirrus clouds are
more likely to form at a higher Rh threshold...
For a 1% change in absolute cirrus coverage with
t5 0.33, the GCM yielded surface temperature changes
(DTs) of 0.438 and 0.588C over the globe and Northern
Hemisphere, respectively.
e... babum!
These results demonstrate that the increased cirrus
coverage, attributable to air traffic, could account
for nearly all of the surface and tropospheric warming
observed over the United States between 1975 and 1994.
e consideriamo anche che non è stato preso in considerazione altro, solo i cirri da contrails..
Changes in aerosol concentrations, greenhouse
gases, and the geographical distribution of clouds, as
well as other air traffic effects, were not taken into account.
For example, ozone formed from air traffic exhaust
is expected to produce a positive radiative forcing
comparable to that from contrails and would result in
additional tropospheric warming below the flight levels
(Penner et al. 1999).
Per finire:
This study indicates that contrails already have
substantial regional effects where air traffic is heavy.
As air travel continues growing in other areas, the impact
may become globally significant.
E questa era la NASA..
Contrails occupy a fairly special niche in atmospheric thermodynamics because they form and produce ice clouds at ambient relative humidities that are less than those required for most natural cirrus cloud formation.
The largest concentrated increases
occurred over the northern Pacific and Atlantic
and roughly correspond to the major air traffic routes
reflected in the ECON distribution..
Contrails often advect hundreds of
kilometers as they develop.
The frequency of clear-sky observations was also
computed for the land air traffic regions. Over the United
States and WASIA, the frequency of clear skies
changed by 21.3% and 1.8% decade21, respectively.
Over EUR and WEUR, clear-sky frequency decreased
by 0.6% and 0.7% decade21, respectively.
The seasonal variations in CC (cirrus coverage, nota mia) and CCI (total cirrus coverage, nota mia) trends over the United States (Fig. 4a) are generally consistent with the seasonal variations of contrail occurrence frequency
Thus, persistent
contrails are likely to form if Rh . 40% and T,2398C
as measured from radiosondes, while cirrus clouds are
more likely to form at a higher Rh threshold...
For a 1% change in absolute cirrus coverage with
t5 0.33, the GCM yielded surface temperature changes
(DTs) of 0.438 and 0.588C over the globe and Northern
Hemisphere, respectively.
e... babum!
These results demonstrate that the increased cirrus
coverage, attributable to air traffic, could account
for nearly all of the surface and tropospheric warming
observed over the United States between 1975 and 1994.
e consideriamo anche che non è stato preso in considerazione altro, solo i cirri da contrails..
Changes in aerosol concentrations, greenhouse
gases, and the geographical distribution of clouds, as
well as other air traffic effects, were not taken into account.
For example, ozone formed from air traffic exhaust
is expected to produce a positive radiative forcing
comparable to that from contrails and would result in
additional tropospheric warming below the flight levels
(Penner et al. 1999).
Per finire:
This study indicates that contrails already have
substantial regional effects where air traffic is heavy.
As air travel continues growing in other areas, the impact
may become globally significant.
E questa era la NASA..
Messaggio orinale: https://old.luogocomune.net/site/newbb/viewtopic.php?forum=61&topic_id=2976&post_id=73376