Identifying the seeding signature in cloud particles from hydrometeor residuals
<p>Cloud seeding experiments for modifying clouds and precipitation have been underway for nearly a century; yet practically all the attempts to link precipitation enhancement or suppression to the presence of seeding materials within clouds remain elusive. In 2019, the Cloud–Aerosol Interacti...
| Main Authors: | , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-04-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/17/2387/2024/amt-17-2387-2024.pdf |
| Summary: | <p>Cloud seeding experiments for modifying clouds and precipitation have been underway for nearly a century; yet practically all the attempts to link precipitation enhancement or suppression to the presence of seeding materials within clouds remain elusive. In 2019, the Cloud–Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) investigated residuals of cloud hydrometeors in seeded and non-seeded clouds with an airborne mini aerosol mass spectrometer (mAMS). The mAMS was utilized in conjunction with a counterflow virtual impactor (CVI) inlet with a cutoff diameter size of approximately 7 <span class="inline-formula">µ</span>m. The evaporated cloud droplets from the CVI inlet as cloud residuals were evaluated through the mAMS. The chlorine (Cl) associated with hygroscopic materials, i.e. calcium chloride (CaCl<span class="inline-formula"><sub>2</sub></span>) and potassium (K), which serve as the oxidizing agents in the flares, is found in relatively higher concentrations in the seeded clouds compared to the non-seeded clouds. In convective clouds, Cl and K as cloud residuals were found even at a vertical distance of 2.25 km from the cloud base. Major findings from the seeding impact are an increase in the number concentration of small (<span class="inline-formula"><</span> 20 <span class="inline-formula">µ</span>m) droplets and an indication of raindrop formation at 2.25 km above the cloud base. It is demonstrated that the seed particle signature can be traced inside clouds along with the microphysical impacts.</p> |
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| ISSN: | 1867-1381 1867-8548 |