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Cloud condensation nuclei in the Amazon Basin: “marine” conditions over a continent?
Author(s) -
Roberts Gregory C.,
Andreae Meinrat O.,
Zhou Jingchuan,
Artaxo Paulo
Publication year - 2001
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl012585
Subject(s) - cloud condensation nuclei , aerosol , supersaturation , amazon rainforest , atmospheric sciences , amazon basin , environmental science , precipitation , radiative forcing , sulfate , structural basin , climatology , geology , chemistry , meteorology , geography , ecology , biology , paleontology , organic chemistry
Cloud condensation nuclei (CCN) are linked to radiative forcing, precipitation, and cloud structure; yet, their role in tropical climates remains largely unknown. CCN concentrations ( N CCN ) measured during the wet season in the Amazon Basin were surprisingly low (mean N CCN at 1% supersaturation: 267±132 cm −3 ) and resembled concentrations more typical of marine locations than most continental sites. At low background CCN concentrations, cloud properties are more sensitive to an increase in N CCN . Therefore, enhanced aerosol emissions due to human activity in the Amazon Basin may have a stronger impact on climate than emissions in other continental regions. In spite of the large organic fraction in the Amazonian aerosol, a detailed analysis of number distributions and size‐dependent chemical composition indicates that sulfate plays an important role in CCN activity.