Condensation nuclei

molecules

300-400 % supersaturation is needed (see Lec.18)
results obtained in

Wilson cloud chamber are the same

Cloud Chamber of
Carl Anderson (ca. 1935)
http://www.orau.org/ptp/collection/miscellaneous/cloudchamber.htm

Starting condensation on
molecules requeres 1200%
supersaturation.

real atmosphere
Insoluble but moistured
Soil
Rocks
Smoke
Organic substances
etc
Soluble
Particles of salts and acids (due

to coal burning)

Coal contains 0.3-20% sulfur ? burning?SO2
SO2 ? H2SO4 (soluble, hygroscopical)
20 million tonns of SO2 arrive the atm. annualy

As a result of earth surface airing, forest fires, volcano eruptions

effect of cloud condensation nuclei on cloud formation. Ships travelling

the ocean off of Europe produce aerosols as they burn fuel, and those aerosols help to form low clouds in the shallow, cool, and moist layer of marine air that exists there.

The above satellite image clearly demonstrates the effect of cloud condensation nuclei on cloud formation. Ships travelling the ocean off of Europe produce aerosols as they burn fuel, and those aerosols help to form low clouds in the shallow, cool, and moist layer of marine air that exists there.

http://www.weatherquestions.com/What_are_condensation_nuclei.htm

1991
Ash plume of Pinatubo during 12, June 1991

http://en.wikipedia.org/wiki/File:Pinatubo_ash_plume_910612.jpg
http://en.wikipedia.org/wiki/File:Volcanic_injection.svg

77.8%
MgCl 10.9%
Sulfur oxides of Mg (magnesium), K (potassium), Ca


Strong wind

(>10 m/s)
2.7*10 10 tons of
marine salt come
into atm. annually

Spray at the Cliffs of Moher, December 2007

nuclei -20%
Burning products – 40%
Soil particles -20%
Unknown origin – 20%

1.

Concentration (number per cm3 near earth surface)
At large cities – 150000
At small towns -35000
At villages -9500
Over oceans, in mountains -940

SPb -280000(RSHU measurements)

condensation process;
in the lower part of a cloud their number

is 102 to 103 per cm3 ;
over sea;

Passive
over land;

Balloon measurements

m for Moscow,
layer 3-6 km
Nuclei concentration variation with height

depends on thermal stratification

Day time: unstable stratification, intensive eddy exchange ? rate of variation is slow

Early morning: stable stratification, weak eddy exchange ? rate of variation is faster

L=1400 m for Moscow,
layer 0-3 km

L=1740 m for Moscow,
layer 3-6 km

and nuclei are transferred to the upper atmospheric layers
In

winter : dwellings heating

In summer eddy exchange is well developed and nuclei are transferred to the upper atmospheric layers
In winter : dwellings heating

Seasonal variation on nuclei concentration in large cities near surface (< 500 m)

Seasonal variation on nuclei concentration at higher layers of the atmosphere (>750 m)

10-4 cm giant nuclei (human

hair diameter ~ 10-3 cm )

Activity of condensation nuclei depends on:
Size
Water absorptivity degree
Surface tension
Surface porosity

Spatially, concentrations are highest over industrial areas (eastern North America, central Europe, and eastern Asia) or where biomass is burned (South America, Africa, and Asia). Water-soluble inorganic species include sulphate, nitrate, and ammonium. There is also a climatologically controlled seasonal cycle, with global mean aerosol loading reaching a maximum in February and a minimum in October.

The skies over Northern India are filled with a thick

soup of aerosol particles all along the southern edge of the Himalayan Mountains, and streaming southward over Bangladesh and the Bay of Bengal. Notice that the air over the Tibetan Plateau to the north of the Himalayas is very clear, whereas the view of the land surface south of the mountains is obstructed by the brownish haze. Most of this air pollution comes from human activities. The aerosol over this region is notoriously rich in sulfates, nitrates, organic and black carbon, and fly ash. These particles not only represent a health hazard to those people living in the region, but scientists have also recently found that they can have a significant impact on the region's hydrological cycle and climate

Credit
Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC
http://visibleearth.nasa.gov/view_rec.php?id=2309