Impacts of long-range-transported mineral dust on summertime convective cloud and precipitation: a case study over the Taiwan region
<p>As one of the most abundant atmospheric aerosols and effective ice nuclei, mineral dust affects clouds and precipitation in the Earth system. Here numerical experiments are carried out to investigate the impacts of dust aerosols on summertime convective clouds and precipitation over the mou...
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| Autores principales: | , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/4c0681175aa44b7b938b42cbed70e6e8 |
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| Sumario: | <p>As one of the most abundant atmospheric aerosols and effective ice nuclei, mineral dust affects clouds and precipitation in the Earth
system. Here numerical experiments are carried out to investigate the impacts of dust aerosols on summertime convective clouds and precipitation
over the mountainous region of Taiwan by acting as ice-nucleating particles. We run the Weather Research and Forecasting model (WRF) with the
Morrison two-moment and spectral-bin microphysics (SBM) schemes at 3 <span class="inline-formula">km</span> resolution, using dust number concentrations from a global chemical
transport model (GEOS-Chem-APM). The case study indicates that the long-range-transported mineral dust, with relatively low number concentrations,
can notably affect the properties of convective clouds (ice and liquid water contents, cloud top height, and cloud coverage) and precipitation (spatial
pattern and intensity). The effects of dust are evident during strong convective periods, with significantly increased ice water contents in the
mixed-phase regime via the enhanced heterogeneous freezing. With both the Morrison and SBM schemes, we see the invigoration effects of dust
aerosols on the convective intensity through enhanced condensation and deposition latent heating. The low-altitude dust particles are uplifted to
the freezing level by updrafts, which, in turn, enhance the convective cloud development through immersion freezing and convective invigoration.
Compared to the Morrison scheme, the SBM scheme predicts more realistic precipitation and different invigoration effects of dust. The differences
are partially attributed to the saturation adjustment approach utilized in the bulk scheme, which leads to a stronger enhancement of condensation at
midlatitudes to low altitudes and a weaker deposition increase at the upper level.</p> |
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