On transition-zone water clouds
A recent field campaign was conducted to measure the properties of thin, warm convective clouds forming under conditions of weak updrafts. During the campaign, short-lived clouds (on the order of minutes) with droplets' effective radius of 1–2 μm and low liquid water path (~ 500 mg m<sup>...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-09-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/9001/2014/acp-14-9001-2014.pdf |
| Summary: | A recent field campaign was conducted to measure the properties of thin,
warm convective clouds forming under conditions of weak updrafts. During the
campaign, short-lived clouds (on the order of minutes) with droplets'
effective radius of 1–2 μm and low liquid water path
(~ 500 mg m<sup>–2</sup>) were measured. These low values are puzzling,
since in most studies an effective radius of 4 μm is reported to
serve as the lower bound for clouds. A theoretical cloud model designed to
resolve the droplet-activation process suggested conditions that favor the
formation of such clouds. Here we show that these clouds, which mark the
transition from haze to cloud, are highly sensitive to the magnitude of the
initial perturbation that initiated them. We define these clouds as
"transition-zone clouds". The existence of such clouds poses a key
challenge for the analysis of atmospheric observations and models, since they
"further smooth" the transition from dry aerosol through haze pockets to
cumulus clouds. |
|---|---|
| ISSN: | 1680-7316 1680-7324 |