Global distribution of Asian, Middle Eastern, and North African dust simulated by CESM1/CARMA
<p>Dust aerosols affect the radiative and energy balance at local and global scales by scattering and absorbing sunlight and infrared light. A previous study suggests that dust size distribution is one of the major sources of uncertainty in modeling the dust global distribution. Climate models...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/13659/2022/acp-22-13659-2022.pdf |
| Summary: | <p>Dust aerosols affect the radiative and energy balance at local and global
scales by scattering and absorbing sunlight and infrared light. A previous
study suggests that dust size distribution is one of the major sources of
uncertainty in modeling the dust global distribution. Climate models
overestimate the fine dust (<span class="inline-formula">≤5</span> <span class="inline-formula">µ</span>m) by an order of magnitude,
while underestimates of the coarse dust (<span class="inline-formula">≥5</span> <span class="inline-formula">µ</span>m) range between 0.5 to 1.5 orders of magnitude compared with the global observations. Here we improved the simulated size distribution of dust aerosol using a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres) coupled with the Community Earth System Model (CESM1/CARMA). Simulated dust mass size distributions peak at around 2–3 <span class="inline-formula">µ</span>m in diameter and increase by 4 orders of magnitude from 0.1 to 2 <span class="inline-formula">µ</span>m. Our model demonstrates that North African, Middle Eastern, and Asian dust accounts for <span class="inline-formula">∼</span> 59.7 %, 12.5 %, and 13.3 % of the global annual mean dust emissions, with the remaining 14.5 % originating from scattered smaller dust sources. The model dust vertical distributions are validated against the NASA Atmospheric Tomography (ATom) field campaign datasets. Both simulations and ATom in situ measurements during the ATom field campaign suggest that dust mass concentrations over the remote ocean drop by 2 to 3 orders of magnitude from the surface to the upper troposphere (200 hPa). Our model suggests that Asian dust contributes to more than 40 % of annual mean dust mass abundances in the global upper troposphere and lower stratosphere (UTLS). The model suggests that Asian dust dominates the dust mass budget in the UTLS of the Asian summer monsoon (ASM) region, with a relative contribution 1–2 orders of magnitude higher than the dust originating from the North African and Middle Eastern deserts.</p> |
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| ISSN: | 1680-7316 1680-7324 |