Analysis of aerosol–cloud interactions and their implications for precipitation formation using aircraft observations over the United Arab Emirates
<p>Aerosol and cloud microphysical measurements were collected by a research aircraft during August 2019 over the United Arab Emirates (UAE). The majority of scientific flights targeted summertime convection along the eastern Al Hajar Mountains bordering Oman, while one flight sampled non-orog...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-08-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/12543/2021/acp-21-12543-2021.pdf |
| Summary: | <p>Aerosol and cloud microphysical measurements were
collected by a research aircraft during August 2019 over the United Arab
Emirates (UAE). The majority of scientific flights targeted summertime
convection along the eastern Al Hajar Mountains bordering Oman, while one
flight sampled non-orographic clouds over the western UAE near the Saudi
Arabian border. In this work, we study the evolution of growing cloud
turrets from cloud base (9 <span class="inline-formula"><sup>∘</sup></span>C) up to the capping inversion level
(<span class="inline-formula">−12</span> <span class="inline-formula"><sup>∘</sup></span>C) using coincident cloud particle imagery and particle
size distributions from cloud cores under different forcing. Results
demonstrate the active role of background dust and pollution as cloud
condensation nuclei (CCN) with the onset of their deliquescence in the
subcloud region. Subcloud aerosol sizes are shown to extend from submicron
to 100 <span class="inline-formula">µ</span>m sizes, with higher concentrations of ultra-giant CCN
(<span class="inline-formula"><i>d</i>>10</span> <span class="inline-formula">µ</span>m) from local sources closer to the Saudi border,
compared with the eastern orographic region where smaller CCN are
observed. Despite the presence of ultra-giant CCN from dust and pollution in
both regions, an active collision–coalescence (C–C) process is not observed
within the limited depths of warm cloud (<span class="inline-formula"><1000</span> m). The
state-of-the-art observations presented in this paper can be used to
initialize modeling case studies to examine the influence of aerosols on
cloud and precipitation processes in the region and to better understand the
impacts of hygroscopic cloud seeding on these clouds.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |