Small ice particles at slightly supercooled temperatures in tropical maritime convection
<p>In this paper we show that the origin of the ice phase in tropical cumulus clouds over the sea may occur by primary ice nucleation of small crystals at temperatures just between 0 and <span class="inline-formula">−5</span> <span class="inline-formula...
| Main Authors: | , , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-03-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/3895/2020/acp-20-3895-2020.pdf |
| Summary: | <p>In this paper we show that the origin of the ice phase in tropical cumulus
clouds over the sea may occur by primary ice nucleation of small crystals at
temperatures just between 0 and <span class="inline-formula">−5</span> <span class="inline-formula"><sup>∘</sup></span>C. This was made possible
through use of a holographic instrument able to image cloud particles at
very high resolution and small size (6 <span class="inline-formula">µ</span>m). The environment in which
the observations were conducted was notable for the presence of desert dust
advected over the ocean from the Sahara. However, there is no laboratory
evidence to suggest that these dust particles can act as ice nuclei at
temperatures warmer than about <span class="inline-formula">−10</span> <span class="inline-formula"><sup>∘</sup></span>C, the zone in which the first
ice was observed in these clouds. The small ice particles were observed to
grow rapidly by vapour diffusion, riming, and possibly through collisions
with supercooled raindrops, causing these to freeze and potentially shatter.
This in turn leads to the further production of secondary ice in these
clouds. Hence, although the numbers of primary ice particles are small, they
are very effective in initiating the rapid glaciation of the cloud, altering
the dynamics and precipitation production processes.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |