scholarly journals How efficient is cloud droplet formation of organic aerosols?

2004 ◽  
Vol 31 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Ulrike Lohmann ◽  
Keith Broekhuizen ◽  
Richard Leaitch ◽  
Nicole Shantz ◽  
Jonathan Abbatt
Keyword(s):  
Organic Aerosols ◽  
Cloud Droplet ◽  
Droplet Formation

scholarly journals An interfacial mechanism for cloud droplet formation on organic aerosols

Science ◽  
2016 ◽  
Vol 351 (6280) ◽  
pp. 1447-1450 ◽  
Author(s):  
C. R. Ruehl ◽  
J. F. Davies ◽  
K. R. Wilson
Keyword(s):  
Organic Aerosols ◽  
Cloud Droplet ◽  
Droplet Formation

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

2016 ◽  
Author(s):  
Sami Romakkaniemi ◽  
Zubair Maalick ◽  
Antti Hellsten ◽  
Antti Ruuskanen ◽  
Olli Väisänen ◽  
...  
Keyword(s):  
Liquid Water ◽  
Measurement Data ◽  
Cloud Droplet ◽  
Droplet Size Distribution ◽  
Liquid Water Content ◽  
Droplet Formation ◽  
Cloud Base ◽  
Topography Effect ◽  
Boreal Environment ◽  
The Hill

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 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 3D 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 geostrophic winds of about 10 m s−1, the hill can cause updrafts of up to 1 m s−1 in the air parcels arriving at the station. This is enough to produce in-cloud supersaturations higher than typically found at the cloud base (SS of ~ 0.2 %), and thus additional cloud droplets may form inside the cloud. In the observations, this is seen in the form of a bi-modal cloud droplet size distribution. The effect is strongest with high winds across the steepest slope of the hill and with low liquid water contents, and its relative importance quickly decreases as these conditions are relaxed. We therefore conclude that, after careful screening for wind speed and liquid water content, the observations at Puijo measurement station can be considered representative for clouds in a boreal environment.

The effect of hygroscopicity on cloud droplet formation

Tellus B ◽  
1996 ◽  
Vol 48 (3) ◽  
pp. 347-360 ◽  
Author(s):  
Markku Kulmala ◽  
Pekka Korhonen ◽  
Timo Vesala ◽  
Hans-Christen Hansson ◽  
Kevin Noone ◽  
...  
Keyword(s):  
Cloud Droplet ◽  
Droplet Formation

The effect of hygroscopicity and trace gases on cloud droplet formation

1995 ◽  
Vol 26 ◽  
pp. S891-S892
Author(s):  
Markku Kulmala ◽  
Pekka Korhonen ◽  
Timo Vesala ◽  
Hans-Christen Hansson ◽  
Kevin Noone ◽  
...  
Keyword(s):  
Trace Gases ◽  
Cloud Droplet ◽  
Droplet Formation
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