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Cloud condensation nuclei

About: Cloud condensation nuclei is a(n) research topic. Over the lifetime, 3096 publication(s) have been published within this topic receiving 156745 citation(s). The topic is also known as: CCN & cloud seed. more


Journal ArticleDOI: 10.1038/326655A0
22 Apr 1987-Nature
Abstract: The major source of cloud-condensation nuclei (CCN) over the oceans appears to be dimethylsulphide, which is produced by planktonic algae in sea water and oxidizes in the atmosphere to form a sulphate aerosol Because the reflectance (albedo) of clouds (and thus the Earth's radiation budget) is sensitive to CCN density, biological regulation of the climate is possible through the effects of temperature and sunlight on phytoplankton population and dimethylsulphide production. To counteract the warming due to doubling of atmospheric CO2, an approximate doubling of CCN would be needed. more

Topics: Cloud albedo (58%), Albedo (54%), Cloud condensation nuclei (54%) more

3,572 Citations

Journal ArticleDOI: 10.1126/SCIENCE.245.4923.1227
Bruce A. Albrecht1Institutions (1)
15 Sep 1989-Science
Abstract: Increases in aerosol concentrations over the oceans may increase the amount of low-level cloudiness through a reduction in drizzle—a process that regulates the liquid-water content and the energetics of shallow marine clouds. The resulting increase in the global albedo would be in addition to the increase due to enhancement in reflectivity associated with a decrease in droplet size and would contribute to a cooling of the earth9s surface. more

Topics: Cloud albedo (59%), Sea salt aerosol (55%), Twomey effect (54%) more

3,217 Citations

Abstract: By increasing droplet concentration and thereby the optical thickness of a cloud, pollution acts to increase the reflectance (albedo) of clouds; by increasing the absorption coefficient it acts to decrease the reflectance. Calculations suggest that the former effect (brightening of the clouds in reflection, hence climatically a cooling effect) dominates for thin to moderately thick clouds, whereas for sufficiently thick clouds the latter effect (climatically a warming effect) can become dominant. more

Topics: Cloud albedo (59%), Twomey effect (58%), Albedo (57%) more

2,630 Citations

Journal ArticleDOI: 10.1016/J.JAEROSCI.2003.10.003
Markku Kulmala1, Hanna Vehkamäki1, Tuukka Petäjä1, M. Dal Maso1  +4 moreInstitutions (3)
Abstract: Over the past decade, the formation and growth of nanometer-size atmospheric aerosol particles have been observed at a number of sites around the world. Measurements of particle formation have been performed on different platforms (ground, ships, aircraft) and over different time periods (campaign or continuous-type measurements). The development during the 1990s of new instruments to measure nanoparticle size distributions and several gases that participate in nucleation have enabled these new discoveries. Measurements during nucleation episodes of evolving size distributions down to 3 nm can be used to calculate the apparent source rate of 3-nm particles and the particle growth rate. We have collected existing data from the literature and data banks (campaigns and continuous measurements), representing more than 100 individual investigations. We conclude that the formation rate of 3-nm particles is often in the range 0.01– 10 cm −3 s −1 in the boundary layer. However, in urban areas formation rates are often higher than this (up to 100 cm −3 s −1 ), and rates as high as 104– 10 5 cm −3 s −1 have been observed in coastal areas and industrial plumes. Typical particle growth rates are in the range 1– 20 nm h −1 in mid-latitudes depending on the temperature and the availability of condensable vapours. Over polar areas the growth rate can be as low as 0.1 nm h −1 . Because nucleation can lead to a significant increase in the number concentration of cloud condensation nuclei, global climate models will require reliable models for nucleation. more

Topics: Nucleation (58%), Particle (53%), Cloud condensation nuclei (52%)

1,901 Citations

Journal ArticleDOI: 10.1038/NATURE01091
12 Sep 2002-Nature
Abstract: Anthropogenic aerosols are intricately linked to the climate system and to the hydrologic cycle. The net effect of aerosols is to cool the climate system by reflecting sunlight. Depending on their composition, aerosols can also absorb sunlight in the atmosphere, further cooling the surface but warming the atmosphere in the process. These effects of aerosols on the temperature profile, along with the role of aerosols as cloud condensation nuclei, impact the hydrologic cycle, through changes in cloud cover, cloud properties and precipitation. Unravelling these feedbacks is particularly difficult because aerosols take a multitude of shapes and forms, ranging from desert dust to urban pollution, and because aerosol concentrations vary strongly over time and space. To accurately study aerosol distribution and composition therefore requires continuous observations from satellites, networks of ground-based instruments and dedicated field experiments. Increases in aerosol concentration and changes in their composition, driven by industrialization and an expanding population, may adversely affect the Earth's climate and water supply. more

Topics: Sea salt aerosol (62%), Aerosol (59%), Cloud condensation nuclei (54%) more

1,848 Citations

No. of papers in the topic in previous years

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Topic's top 5 most impactful authors

Markku Kulmala

104 papers, 12.9K citations

Athanasios Nenes

74 papers, 4.3K citations

Meinrat O. Andreae

56 papers, 12.9K citations

James G. Hudson

44 papers, 2.1K citations

Ulrich Pöschl

43 papers, 3.7K citations

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