Aerosol pollution over Northern India and Bangladesh - NASA

Cloud condensation nuclei or CCNs (also known as cloud seeds) are small particles (typically 0.0002 mm, or 1/100 th the size of a cloud droplet [1]) about which cloud droplets coalesce. Water requires a non-gaseous surface to make the transition from a vapour to a liquid. In the atmosphere, this surface presents itself as tiny solid or liquid particles called CCNs. When no CCNs are present, water vapour can be supercooled below 0 °C (32 °F) before droplets spontaneously form (this is the basis of the cloud chamber for detecting subatomic particles). Download high resolution version (1100x1450, 311 KB)Aerosol pollution over Northern India and Bangladesh File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Download high resolution version (1100x1450, 311 KB)Aerosol pollution over Northern India and Bangladesh File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Cumulus of fair weather Different cloud types A cloud is a visible mass of condensed droplets or ice crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... Look up coalescence in Wiktionary, the free dictionary. ... Vapor (US English) or vapour (British English) is the gaseous state of matter. ... A liquid will assume the shape of its container. ... Boundaries: Phase, Pressure, Temperature Evaporation/Sublimation Whenever a water molecule leaves a surface, it is said to have evaporated. ... A degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701-1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... The cloud chamber, also known as the Wilson chamber, is used for detecting particles of ionizing radiation. ...

Size, abundance, and composition

A typical raindrop is about 2 mm in diameter, a typical cloud droplet is on the order of 0.02 mm, and a typical cloud condensation nucleus (aerosol) is on the order of 0.0001 mm or 0.1 micrometer or greater in diameter. The number of cloud condensation nuclei in the air can be measured and ranges between between around 100 to 1000 per cubic centimeter. The total mass of CCNs injected into the atmosphere has been estimated at 2x10¹² kg over a year's time. Large concentrations of particulates are also responsible for haze in areas with lower humidity. This dry haze also has an effect on climate by either absorbing or reflecting radiation (see albedo). http://visibleearth. ... Severe haze affecting Ampang, Kuala Lumpur, Malaysia in August 2005 Moon over red and blue haze For the progressive rock band Haze, see Haze (band). ... Humidity is the concentration of water vapor in the air. ... Albedo is the measure of reflectivity of a surface or body. ...

There are many different types of atmospheric particulates that can act as CCN. The particles may be composed of dust or clay, soot or black carbon from grassland or forest fires, sea salt from ocean wave spray, soot from factory smokestacks or internal combustion engines, sulfate from volcanic activity, phytoplankton or the oxidation of sulfur dioxide and secondary organic matter formed by the oxidation of VOCs. The ability of these different types of particles to form cloud droplets varies according to their size and also their exact composition, as the hygroscopic properties of these different constituents are very different. Sulfate and sea salt, for instance, readily absorb water whereas soot, organic carbon and mineral particles do not. This is made even more complicated by the fact that many of the chemical species may be mixed within the particles (in particular the sulfate and organic carbon). Additionally, while some particles (such as soot and minerals) do not make very good CCN, they do act as very good ice nuclei in colder parts of the atmosphere. Particulates, alternately referred to as Particulate Matter (PM) , aerosols or fine particles are tiny particles of solid or liquid suspended in the air. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of natural clays. ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the... In inorganic chemistry, a sulfate (IUPAC-recommended spelling; also sulphate in British English) is a salt of sulfuric acid. ... This article is about volcanoes in geology. ... Diagrams of some typical phytoplankton Phytoplankton refers to the autotrophic component of the plankton that drifts in the water column. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... ... A hygroscopic substance is a substance that absorbs water readily from its surroundings. ... Ice nuclei are particles that act as nuclei for the formation of ice crystals in the atmosphere. ...

The number and type of CCNs can affect the lifetimes and radiative properties of clouds as well as the amount and hence have an influence on climate change [2] [3], but the details of this are still not well understood but are the subject of much research by many groups worldwide. Cumulus of fair weather Different cloud types A cloud is a visible mass of condensed droplets or ice crystals suspended in the atmosphere above the surface of the Earth or another planetary body. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years Climate change refers to the variation in the Earths global climate or regional climates over time. ...

Phytoplankton bloom in the North Sea and the Skagerrak - NASA

Phytoplankton bloom in the North Sea and the Skagerrak - NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Phytoplankton bloom in the North Sea and the Skagerrak - NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

Phytoplankton role

Sulfate aerosol (SO₄^2- and methanesulfonic acid droplets) act as CCNs. These sulfate aerosols form partly from the dimethyl sulfide (DMS) produced by phytoplankton in the open ocean. Large algal blooms in ocean surface waters occur in a wide range of latitudes and no doubt contribute considerable DMS into the atmosphere to act as nuclei. The idea that an increase in global temperature would also increase phytoplankton activity and therefore CCN numbers was seen as a possible natural phenomenon that would counteract climate change. This is known as the CLAW hypothesis [4] (named after the authors' initials of a 1987 Nature paper) but no conclusive evidence to support this has yet been reported. Dimethyl sulfide causes that distinctive smell from your St. ... An algal bloom is a relatively rapid increase in the population of (usually) phytoplankton algae in an aquatic system. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years Climate change refers to the variation in the Earths global climate or regional climates over time. ...

See also

• Bergeron process

Definition The Bergeron Process is the formation of precipitation in the cold clouds of the mid and upper latitudes by ice crystal growth. ...

References and external links

• R. Charlson, James Lovelock, M. Andreae and S. Warren (1987). Oceanic phytoplankton, atmospheric sulphur, cloud albedo and climate. Nature, 326, 655-661.
• Apollo.lsc.vsc.edu
• www.agu.org
• www.grida.no
• Condensation Nucleus National Science Digital Library - Cloud Condensation Nucleus
• DMS and Climate
• Dimethyl Sulfide - Summary
• AGU Association between CCN and Phytoplankton