Shipborne measurements of total particle concentrations are widespread, but measurements of cloud condensation nuclei
(CCN), particle composition, and BC (see sidebar "Developments in aerosol microphysical measurements") are concentrated over the Atlantic and Arctic.
Objective: The oxidation of volatile organic compounds (VOC) in the atmosphere has crucial effects on aerosol particle formation, hence on the budget of cloud condensation nuclei
, and thus on climate.
When condensation nuclei
(assumed to be dust aerosols on Mars) are too rare, condensation is impeded, leaving substantial amounts of excess vapour.
17 Science that there were more cloud condensation nuclei
, along with other measures of aerosols, above regions with a lot of human activity compared with more pristine areas.
Dr Graham Jones of Southern Cross University in Lismore has shown that the algae present in healthy reefs produce a volatile substance called dimethylsulphide (DMS), which oxidises in the atmosphere to produce what are known as cloud condensation nuclei
Stephen Salter, an engineer at the University of Edinburgh, suggests having ships inject seawater into the atmosphere, where salt particles would serve as extra cloud condensation nuclei
This augments the natural process, where sea salt from the oceans provides water vapor with the cloud condensation nuclei
Solar influence can manifest itself in different ways: fluctuations of solar irradiance (total energy), which has been measured in satellites and related to the sunspot cycle; variability of the ultraviolet portion of the solar spectrum, which, in turn, affects the amount of ozone in the stratosphere; and variations in the solar wind that modulate the intensity of cosmic rays, which, upon impact into the Earth's atmosphere, produce cloud condensation nuclei
, affecting cloudiness and, thus, climate.
In supersaturated conditions, water droplets themselves may act as condensation nuclei
Other topics under discussion include simulation of fuel consumption and emissions in typical traffic circumstances in Belgium, atmospheric volatile organic compounds in a Portuguese mountain region, and generation of monodisperse aerosols through condensation nuclei
In clouds having their entire depth at temperatures greater than 0[degrees]C, rain may form from the so-called warm rain process, where cloud droplets nucleated upon special aerosol particles (called cloud condensation nuclei
, or CCN) near the base of the cloud grow by condensation as they ascend within the cloud, and once achieving large enough sizes, grow by collection of smaller drops to produce drizzle or raindrops.
The more exhaust particles, the more condensation nuclei