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URN: urn:nbn:de:swb:90-722134

Aerosol-landscape-cloud interaction : Signatures of topography effect on cloud droplet formation

Romakkaniemi, S.; Maalick, Z.; Hellsten, A.; Ruuskanen, A.; Väisänen, O.; Ahmad, I.; Tonttila, J.; Mikkonen, S.; Komppula, M.; Kühn, T.

Abstract:
Long-term in situ measurements of aerosol–cloud interactions are usually performed in measurement stations residing on hills, mountains, or high towers. In such conditions, the surface topography of the surrounding area can affect the measured cloud droplet distributions by increasing turbulence or causing orographic flows and thus the observations might not be representative for a larger scale. The objective of this work is to analyse, how the local topography affects the observations at Puijo measurement station, which is located in the 75 m high Puijo tower, which itself stands on a 150 m high hill. The analysis of the measurement data shows that the observed cloud droplet number concentration mainly depends on the cloud condensation nuclei (CCN) concentration. However, when the wind direction aligns with the direction of the steepest slope of the hill, a clear topography effect is observed. This finding was further analysed by simulating 3-D flow fields around the station and by performing trajectory ensemble modelling of aerosol- and wind-dependent cloud droplet formation. The results showed that in typical conditions, with geo ... mehr


Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Forschungsbereich Troposphäre (IMK-TRO)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator ISSN: 1680-7316, 1680-7324
URN: urn:nbn:de:swb:90-722134
KITopen ID: 1000072213
Erschienen in Atmospheric chemistry and physics
Band 17
Heft 12
Seiten 7955-7964
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