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P. TUNVED J. STRÖM M. KULMALA V.-M. KERMINEN M. DAL MASO B. SVENNINGSON C. LUNDER H.-C. HANSSON 《Tellus. Series B, Chemical and physical meteorology》2008,60(4):473-484
We use a recently developed parametrization to estimate the regional particle field in the summer time troposphere over Scandinavia that would result if the forest were the only source of particles. The calculated field is compared with available observational data. It is concluded that the needle leaf forest above 58°N alone is capable of producing aerosol mass concentrations corresponding to 12–50% of today's values in the boundary layer over Scandinavia. We also demonstrate that the forest itself could produce up to 200 CCN per cubic centimetre on average over Scandinavia and further show that an increase in temperature by 5.8 °C compared to today's average temperature could increase this CCN population by 40%. The study shows that we are able to approximate the natural aerosol field resulting from biogenic emissions over the boreal forest in the northern hemispheric region. This information provide an important contribution in the evaluation of the climate effect caused by anthropogenic emissions of particles over the forest and also opens the possibility to better address the climate feedbacks believed to be associated with the boreal region. 相似文献
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Changes in aerosol size- and phase distributions due to physical and chemical processes in fog 总被引：4，自引：0，他引：4
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PASI AALTO KAARLE HÄMERI EDO BECKER RODNEY WEBER JAAN SALM JYRKI M. MÄKELÄ CLAUDIA HOELL COLIN D. O'DOWD HANS KARLSSON HANS&#;CHRISTEN HANSSON MINNA VÄKEVÄ ISMO K. KOPONEN GINTAUTAS BUZORIUS MARKKU KULMALA 《Tellus. Series B, Chemical and physical meteorology》2001,53(4):344-358
Particle concentrations and size distributions have been measured from different heights inside and above a boreal forest during three BIOFOR campaigns (14 April–22 May 1998, 27 July–21 August 1998 and 20 March–24 April 1999) in Hyytiälä, Finland. Typically, the shape of the background distribution inside the forest exhibited 2 dominant modes: a fine or Aitken mode with a geometric number mean diameter of 44 nm and a mean concentration of 1160 cm−3 and an accumulation mode with mean diameter of 154 nm and a mean concentration of 830 cm−3 . A coarse mode was also present, extending up to sizes of 20 μm having a number concentration of 1.2 cm−3 , volume mean diameter of 2.0 μm and a geometric standard deviation of 1.9. Aerosol humidity was lower than 50% during the measurements. Particle production was observed on many days, typically occurring in the late morning. Under these periods of new particle production, a nucleation mode was observed to form at diameter of the order of 3 nm and, on most occasions, this mode was observed to grow into Aitken mode sizes over the course of a day. Total concentrations ranged from 410–45 000 cm−3 , the highest concentrations occurring on particle production days. A clear gradient was observed between particle concentrations encountered below the forest canopy and those above, with significantly lower concentrations occurring within the canopy. Above the canopy, a slight gradient was observed between 18 m and 67 m, with at maximum 5% higher concentration observed at 67 m during the strongest concentration increases. 相似文献