A more recent report from NASA documented a 1 percent per decade increase
in cirrus cloud cover over the United States, presumably due to increased air travel.
The 27 - 28 October 1986 FIRE IFO cirrus case study: spectral properties
of cirrus cloud in the 8 - 12 um window.
Chemically, there will be an increase in ozone depletion (due to increases in heterogenous surface chemistry in the stratosphere), increases in acid rain, possibly an increase in
high cirrus cloud cover due to indirect effects of the sulphates on cloud lifetime.
Eleftheratos, K., C.S. Zerefos, P. Zanis, D.S. Balis, G. Tselioudis, K. Gierens, and R. Sausen, 2007: A study on natural and manmade global interannual fluctuations of
cirrus cloud cover for the period 1984 - 2004.
«Only after these questions are addressed could one move further to explore the costs and feasibility of
cirrus cloud thinning.»
Zerefos, C.S., K. Eleftheratos, D.S. Balis, P. Zanis, G. Tselioudis, and C. Meleti, 2003: Evidence of impact of aviation
on cirrus cloud formation.
You report a proposal to reverse global warming by seeding the atmosphere to
reduce cirrus cloud cover (26 January, p...
Geoengineering Is Easier Said Than Done] «You remove the water vapor, you remove the humidity and you prevent the normal
cirrus cloud formation,» Lohmann said.
Long, white vapor trails blending
into cirrus clouds and cooling over southeastern England during World War II have led researchers to believe that contrails could influence climate.
goodsprk: It relies on not simply CO2, but on feedback from increased CO2 raising the temperature which increases the water vapor in the atmosphere which the alarmist assume will actually breaking up the low level clouds and forming high
level cirrus clouds that will trap more heat.
Francis, P.N., P. Hignett, and A. Macke, 1998: The retrieval of
cirrus cloud properties from aircraft multi-spectral reflectance measurements during EUCREX» 93.
The authors propose that higher ocean surface temperatures directly cause the decline in
cirrus clouds by changing the dynamics of cloud formation and rainfall.
Condensation trails («contrails») from aircraft exhaust may expand to
form cirrus clouds and these and cosmic ray relations to clouds are addressed in Chapter 2.
A decrease in
cirrus cloud area would have a cooling effect by allowing more heat energy, or infrared radiation, to leave the planet.
Depending on how much moisture is in the air, contrails can be long - lived, spreading out to look more like the
wispy cirrus clouds made by Nature.
For Horizon Zero Dawn, Guerrilla need a solution that can fill a sky with evolving and realistic results that closely match highly detailed reference images which represent high
altitude cirrus clouds and all of the major low level cloud types, including thick billowy cumulus clouds.
The researchers found that cumulus cloud towers produced
less cirrus clouds when they moved over warmer ocean regions.
Like clear air,
cirrus clouds absorb the Earth's radiation and then emit longwave, infrared radiation both out to space and back to the Earth's surface.
Emissions, they discovered, increased the fraction of
cirrus clouds where vapor trails were most prevalent but decreased the fraction in some areas by increasing the temperature and consequently decreasing the relative humidity in the lower atmosphere.
Analyzing data collected over a 20 - month period, scientists from NASA's Goddard Space Flight center in Greenbelt, Md., and the Massachusetts Institute of Technology found that the number of
cirrus clouds above the Pacific Ocean declines with warmer sea surface temperatures.
But if done incorrectly, the activity could
produce cirrus clouds where none existed before, contributing to the very problem it's meant to solve, she added.
When I, with some colleagues at NASA, attempted to determine how clouds behave under varying temperatures, we discovered what we called an «Iris Effect,» wherein upper - level
cirrus clouds contracted with increased temperature, providing a very strong negative climate feedback sufficient to greatly reduce the response to increasing CO2.
Specifically, whereas Lindzen's experiment predicts that
cirrus clouds change in extent to reduce warming at the surface by anywhere from 0.45 to 1.1 degrees, Lin's experiment predicts that changes in the tropical clouds will help warm the surface by anywhere from 0.05 to 0.1 degree (Lin et al. 2001).
If the same happens for GHGs remains to be seen (but the trend over the last decades is the other way out
for cirrus clouds).
Expectation of small but positive CO2 - greenhouse warming is consistent with his claims of strong negative feedbacks by upper tropospheric water vapor or
cirrus clouds which would lose sense without initial warming in the global tropics.
Another less - explored option for reducing the effects of sunlight at the Earth's surface would be to «remove»
cirrus clouds from the atmosphere.
The third experiment would explore the potential for
making cirrus clouds in the upper atmosphere more porous to radiation bouncing back into space from Earth.
«
If cirrus cloud thinning is not done carefully, the effect could be additional warming rather than the intended cooling.»
The effect of high thin
cirrus clouds at night would be very small compared with that of the low thick stratocumulus clouds.
«You remove the water vapor, you remove the humidity and you prevent the
normal cirrus cloud formation,» Lohmann said.
Smith, S.A., and A.D. Del Genio, 2001: Analysis of aircraft, radiosonde, and radar observations in
cirrus clouds observed during FIRE II: The interactions between environmental structure, turbulence, and cloud microphysical properties.
It indicated that contrails — white lines of Vapor left by jet engines — also have big knock - on effects by adding to the formation of high - altitude, heat -
trapping cirrus clouds as the lines break up.
The study, by experts at the DLR German Aerospace Center, estimated that the net warming effect for the Earth of contrails and
related cirrus clouds at any one time was 31 milliwatts per square meter, more than the warming effect of accumulated CO2 from aviation of 28 milliwatts.
Seeding the atmosphere with dust would paradoxically thin
out cirrus clouds, Lohman said.
Their relatively good spectral resolution makes infrared sounders very useful for the determination of cloud properties (day and night), and their coarse spatial resolution has less effect on clouds with large spatial extents
like cirrus clouds.
As to the effect mentioned in your comment, as I understand it, cumulus clouds reflect infrared radiation back into space
while cirrus clouds catch infrared radiation leaving earth and reflect it back to earth.
ACCRI also commissioned a study that suggests that the Earth's climate is affected by contrails and aviation -
induced cirrus clouds.
«While low clouds have a predominantly cooling effect due to their shading of sunlight,
most cirrus clouds have a net warming effect on the Earth,» Spencer said.
In contrast, an increase in the intensity of sub-tropical anticyclones observed in ECHAM4 results from a tropospheric warming promoted by
excessive cirrus clouds attributed to a scale - dependent response in the relevant parametrization (Stendel and Roeckner, 1998).
If the Sun is close to the horizon and
feathery cirrus clouds sit high in the sky, «ghost» images of the Sun will sometimes materialize on either side of it, giving the appearance of three Suns shining in the sky.
NASA's recent Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment focused on
anvil cirrus clouds, an important but poorly understood element of our climate system.