Supersaturated Ice


A) is in contradiction to B) and C) "Supersaturation by the way means ABOVE 100% For the real info: tracking\pages\cirrus-test.html ...Or see the ready made ( from data of cirrus-test page ) jpg picture ------->

a) temp. and
RH for "persistant contrails"

B)
"Andrew Heymsfield, Larry Miloshevich, and Steven
Aulenbach, along with Glen Sachse (NASA Langley) and
Sam Oltmans (NOAA) found that the relative humidities
with respect to water which are required to form ice
crystals in cirrus clouds decline from almost 100% near
40 degrees C to 75 or 80% from -55 to -65 degrees C.
see jpg in a)

C)
Heymsfield et al GRL 1998
<saved in downloads>
http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/15504/Heymsfield%20et%20al%20GRL%201998.pdf?sequence=1
<saved in downloads> or see this related abstract or see cirrus-test  
http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281995%29052%3C4302%3ARHATIO%3E2.0.CO%3B2
the pdf see next link
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281995%29052%3C4302%3ARHATIO%3E2.0.CO%3B2
also here...1520-0469(1995)052_4302_RHATIO_2.0
or http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA376290
#01  Heymsfield 1998 Andrew J. Heymsfield
Larry Miloshevich  
An expression is
since ice crystals must have nucleated prior to
the peak and therefore at a lower RH. HM found that
these peak RH values — their empirical aRHhn(T)"
curve — varied from water-saturation at temperatures
above -39 C to 75% RH (with respect to water) at -
55C. HM also determined a lower bound on RHnuc in
the temperature range -35 to -47C — about 10% below
the RHhn curve — based on the maximum RH measured
in "clear air" in a non-orographic environment
during FIRE-II. In this article we use RH and microphysical
data from balloon launches near Boulder, Colorado
and from the FIRE-II and SUCCESS experiments
to further explore bounds on RHnvc(T), particularly at
colder temperatures. Most data presented in this paper
represent mid-latitude, continental, non-convective
environments. < link and local pdf file Heymsfield >
xx
An expression is given for the peak RH with respect
to water in the wave clouds (RHJ, which decreases from 100% above -39C to 73%
at -56C; RHhn represents the condition required for ice nucleation in the wave clouds,
and is shown to be more consistent with the homogeneous freezing of sulfuric acid
solution droplets than ammonium sulfate solution droplets.
106
Aircraft measurements made in cirrus during FIRE II show highly ice-supersaturated
regions in clear air, placing a lower bound on the RH required for cirrus formation
approximately equal to (RHlm-10)%. Measurements from a balloon-borne formvar ice
crystal replicator are reported which show the vertical structure of cirrus to generally
consists of three microphysically distinct regions: a highly ice-supersaturated ice production
region near cloud top, an ice-supersaturated ice crystal growth region, and a
sublimation region near cloud base formed by fallout of ice into ice-subsaturated air.
< online link and my backup file here AFRL-VS-HA-TR-1998-0051 >

given for the peak RH with respect to water in the wave clouds (RHhn), which decreases from 100% above −39C

to 73% at −56C; RHhn represents the condition required for ice nucleation in the wave clouds and is shown

to be more consistent with the homogeneous freezing of sulfuric acid solution droplets than ammonium sulfate

solution droplets.

Aircraft measurements made in cirrus during FIRE II show highly ice-supersaturated regions in clear air,

placing a lower bound on the RH required for cirrus formation approximately equal to (RHhn–10)%.

< So for cirrus clouds or "persistent contrails to form we need a humidity of 100% minus 10% = 90 RH. 73% of RH at
−56C
I'm only 1 degree off at that level see chart a)  >
----------------------------------------------------------------------------------------------------------------------------------------------------------------
<info from 2005>
" Contrail cirrus can account for all of observed warming over
USA between 1975 & 1994 based on the scaling approach
- Ozone impact not included! '
http://www.techtransfer.berkeley.edu/aviation05downloads/Minnis.pdf
<in case pdf file will be removed from the Internet, I made a backup>
most cloud layers form at lower altitudes where the moisture levels commonly exceed relative humidity levels of 70%
pages\Persistent-Contrails.html

An expression is

given for the peak RH with respect to water in the wave clouds (RHhn), which decreases from 100% above −39C

to 73% at −56C; RHhn represents the condition required for ice nucleation in the wave clouds

I'm only off by one degree Celsius (-57C) . See figure a) ..
See page cirrus-test
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
http://science-edu.larc.nasa.gov/contrail-edu/science.html
Contrails only form at very high altitudes (usually above 8 km) where the air is extremely cold (less than -40 degrees C).

http://www.chemtrailcentral.com/ubb/Forum1/HTML/000741.html
True enough Thermit, but my point is "a real proper contrail stretches across the sky" is not true! Some may, under right conditions, but most don't, they quickly dissipate. How many contrails do you recall as a child that stretched across the sky??? I remember zero!It is my assumption that by telling kids "a real proper contrail stretches across the sky" when the kids look up and see all the chemtrails stretched across the sky they will think they're "real proper" contrails.Brainwashing as fas as I'm concerned!

You mention in your paper on http://hyperion.gsfc.nasa.gov/AEAP/98jensen1pos.html
about the evolution of persistent contrails that supersaturation (125% humidity) must be the cause of the highly persistent contrails but in another paper you mention homogeneously nucleated sulfate aerosols   http://hyperion.gsfc.nasa.gov/AEAP/98brownabs.html

My question is have the variations in chemical make-up of the highly persistent contrails being spotted everywhere been determined? If so could you point me to the studies and the data that should explain this?

Homogeneously nucleated sulfate aerosols are more hygroscopic then other particulate from what I gather from your writing and from other info I have gathered.

Is this the primary cause?

Thanks for your time in considering my questions.

Sincerely,
Michael McDonnough
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#02
A few years later NASA is lowering the relative humidity for  "contrails" after the chemtrail spraying went on for some years.
NASA disinfo here:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040075756_2004077687.pdf
<saved as:quantitative-infrared-NASA in downloads>
<info from 2004>
Quantitative Infrared Spectroscop_y. o f Minor Constituents of
Earth’s Atmosphere
Charles Chackerian, Jr., Lawrence P. Giver
The observed rate of contrail spreading and maintenance
of optical depths larger than 0.1 can be
explained simply by the growth and precipitation of
ice crystals that nucleate during the initial contrail
formation if the environmental humidity is high
enough (relative humidity with respect to ice greater
than 125%)
. This result is consistent with the high
humidities observed in regions where the persistent
contrails formed on May 12. Also, the simulations
indicate that the humidity must be high throughout a
depth of at least several hundred meters below the
contrail to allow the crystals to continue growing as
they fall.
Point of Contact: E. Jensen
ejensen@sky.arc.nasa.gov
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#03
http://www.atmos-chem-phys-discuss.net/4/7433/2004/acpd-4-7433-2004-print.pdf
<acpd-4-7433-2004-print>
<info from 2004>
The ice saturation ratio
15 (si ) at the tropopause indicated by the water vapor and temperature measurements
is about 2.3–2.4 (i.e. about 130–140% supersaturation with respect to ice).

Fig. 4. Peak ice saturation ratios achieved at any location or time in simulations with different
initial concentrations of sulfate aerosols and cooling rates are plotted. The range of ice saturation
ratios shown here correspond to relative humidities with respect to liquid ranging from
about 80–100%.
< see figure A) which shows 60-100%. And by the way, why this wide range of 80-100%? Aerosols? Chemtrail aerosols? The Swedish findings told of 150% RH with respect to ice >
7459
Fig. 5. The ratio of aerosol radius divided by the equilibrium radius is plotted versus equilibrium
radius for different accommodation coefficients (red and blue curves). The aerosol size
distribution used in the simulations is shown for reference. If c is significantly decreased by
surface impurities, the aerosols can be much more concentrated and less likely to freeze than
they would be in equilibrium with the vapor

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#04
http://e-collection.library.ethz.ch/eserv/eth:5071/eth-5071-02.pdf
or <eth-5071-02>
Backscatter and Humidity Measurements in Cirrus
and Dust Clouds using Balloon Sondes
1.3.1 Influence of Aerosols on the Climate
Aerosols also cause an indirect effect by
acting as cloud condensation nuclei (CCN) for liquid clouds or as ice nuclei (IN) for ice
clouds and therefore modify cloud optical properties and persistence. In the complete
absence of aerosols, cloud droplets could not form without supersaturations of several
hundred percent. Consequently aerosols largely affect the initial cloud droplet number
concentration, cloud lifetime and albedo (Giannakaki et al., 2009).
As described by IPCC (2007), uncertainties about the aerosol effects for mineral dust
are particularly high.
2.1. Cirrus clouds
For
example, at temperatures lower than 233 K (-40◦C)
< http://www.metric-conversions.org/temperature/kelvin-to-celsius.htm >
this process requires airmasses in a
state of substantial supersaturation which is generally larger than 40% (Spichtinger et al.,
2003)).
http://www.researchgate.net/publication/24391813_Spreading_and_Growth_of_Contrails_in_a_Sheared_Environment

Strong radiative heating (with rates up to
10 K d'1) drives a local updraft and lofts the contrail core several hundred meters.
The observed rate of contrail spreading and maintenance of optical depths larger
than 0.05 can be approximately explained simply by growth and precipitation of
ice crystals nucleated during the initial contrail formation if the environmental
humidity is very high (relative humidity with respect to ice > 125%)

Satellite observations of relatively young, linear con-
trails have shown that they cover only about 0.2 to
1% of the sky, even in regions with heavy air traffic
[Mannstein, 1996; Sassen, 1997].
< Exactly! And the first chemhaze I saw on Crete on October 2001. First chemtrails in Finland on October 2011 >
Hence, these read-
ily identifiable contrails probably do not have a sub-
stantial impact on Earth’s radiation budget or climate.
However, recent satellite observations have documented
cases in which contrails persisted for several hours and
spread extensively to cover large areas [Minnis et al.,
1998]. These aged contrails eventually look very much
like natural cirrus clouds, both in terms of their visual
appearance and their microphysical composition [Spin-
hirne, personal communication]. Since these persistent
contrails have long lifetimes and grow to cover large
areas, they have the greatest potential for affecting re-
gional or global climate. Hence, the key issues concern-
ing the impact of contrails on climate are how often
these persistent, spreading contrails form, and what en-
vironmental conditions are required for their formation.
The processes that drive contrail spreading are hor-
izontal diffusion and vertical shear of the horizonta
http://www.sovereignindependentuk.co.uk/2012/11/26/sky-wreck-on-the-shore-of-planet-earth
Chemtrail Air-craft Has ‘Planet Under Pressure’
http://socalskywatch.wordpress.com/2012/11/27/six-day-chemtrail-assault-video/#
Southern California Sky Watch

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#05
http://www.sat.ltu.se/members/mmilz/publications/mahapatra09_report_nearlyfinal.pdf
or..
<mahapatra09_report_nearlyfinal>
A Review of Ice Particle Formation Models
P. Mahapatra, M. Milz and S. Buehler
Satellite Atmospheric Science Group, Department of Space Science, Lule University of Technology, Kiruna, Sweden

II. HOMOGENEOUS ICE NUCLEATION
The formation of cirrus clouds in environments with moderate
to strong upward draughts or few germs is dominated
by homogeneous nucleation, as elaborated by Tompkins et al.
[5]. The relative humidity with respect to ice increases up to a
critical threshold RHcrit of supersaturation as high as 150%,
before nucleation begins under conditions of low temperature
and large difference between the vapour pressures of liquid
water and ice saturation.


--------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Reflections:
Satellite observations of relatively young, linear con-
trails have shown that they cover only about 0.2 to
1% of the sky, even in regions with heavy air traffic
[Mannstein, 1996; Sassen, 1997].
< Exactly! And the first chemhaze I saw on Crete on October 2001. First chemtrails in Finland on October 2011 >
-------------------
However, recent satellite observations have documented
cases in which contrails persisted for several hours and
spread extensively to cover large areas [Minnis et al.,
1998]. These aged contrails eventually look very much
like natural cirrus clouds, both in terms of their visual
appearance and their microphysical composition [Spin-
hirne, personal communication]
-------------------
[5]. The relative humidity with respect to ice increases up to a
critical threshold RHcrit of supersaturation as high as 150%,
before nucleation begins under conditions of low temperature
and large difference between the vapour pressures of liquid
water and ice saturation.

< this sounds like a relative humidity with respect to water of 96% >
---------------------------------------------------------------------------------------------------------------------------------------------------------------
#01
Andrew J. Heymsfield Larry Miloshevich  1998
HM also determined a lower bound on RHnuc in
the temperature range -35 to -47C — about 10% below
the RHhn curve
#02
NASA 2004
(relative humidity with respect to ice greater
than 125%)
#03
European Geosciences Union 2004
 about 130–140% supersaturation with respect to ice).
humidities with respect to liquid ranging from
about 80–100%.
< so is 100% with respect to liquid the same as 140% with respect to ice? >
#04
MARTIN BRABEC Dipl. Geogr., University of Zurich  2011
Cirrus clouds... at temperatures lower than 233 K (-40◦C)
this process requires airmasses in a
state of substantial supersaturation which is generally larger than 40% (Spichtinger et al.,
2003)).
#05
A Review of Ice Particle Formation Models
P. Mahapatra, M. Milz and S. Buehler
Satellite Atmospheric Science Group, Department of Space Science, Lule University of Technology, Kiruna, Sweden
 The relative humidity with respect to ice increases up to a
critical threshold RHcrit of supersaturation as high as 150%,
before nucleation begins under conditions of low temperature
and large difference between the vapour pressures of liquid
water and ice saturation.

< 150% RH with respect to ice is 101% RH with respect to water >
-------------------------------------------------------------------------------------------------------------------------------------------
RH_WMO or via Internet http://www.rhs.com/papers/RH_WMO.pdf
xx


xxxx



-----------------------------------------------------------------------------------------------------------------------------------------------------------------
1.3.1 Influence of Aerosols on the Climate
Aerosols also cause an indirect effect by
acting as cloud condensation nuclei (CCN) for liquid clouds or as ice nuclei (IN) for ice
clouds and therefore modify cloud optical properties and persistence. In the complete
absence of aerosols, cloud droplets could not form without supersaturations of several
hundred percent. Consequently aerosols largely affect the initial cloud droplet number
concentration, cloud lifetime and albedo (Giannakaki et al., 2009).

So the air quality aka ice nuclei content is the most important aspect. Lets assume that the air over Sweden is cleaner than over the USA. So what was the Swedish findings?
150% with respect to water. Just like with rain.. watch out for the dew point. Dew point and temperature must much. Only then you have rain or snow or "contrail-cirrus" clouds
Unless.   they spray more nucley via airplanes to make artificial cirrus clouds or "persistent contrails".