Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia
<p>Utilizing the well-calibrated, high-spectral-resolution equal-quality performance of daytime and nighttime (09:30 and 21:30 local solar Equator-crossing time (local solar ECT)) products of the Infrared Atmospheric Sounder Interferometer (IASI) from the Laboratoire de Météorologie Dynamique...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/5435/2023/acp-23-5435-2023.pdf |
| _version_ | 1827946689887993856 |
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| author | J. Z. Tindan J. Z. Tindan Q. Jin B. Pu |
| author_facet | J. Z. Tindan J. Z. Tindan Q. Jin B. Pu |
| author_sort | J. Z. Tindan |
| collection | DOAJ |
| description | <p>Utilizing the well-calibrated, high-spectral-resolution
equal-quality performance of daytime and nighttime (09:30
and 21:30 local solar Equator-crossing time (local solar ECT)) products
of the Infrared Atmospheric Sounder Interferometer (IASI) from the
Laboratoire de Météorologie Dynamique (LMD), this study investigates
the day–night differences in dust aerosols over the global dust belt of
North Africa, the Middle East, and Asia. Both daytime dust
optical depth (DOD) and nighttime DOD at 10 <span class="inline-formula">µ</span>m show high consistency with solar and
lunar observations of coarse-mode aerosol optical depth (CAOD) from AErosol
RObotic NETwork (AERONET) sites across the dust belt, with correlation
coefficients of 0.8–0.9 for most sites. Both IASI DOD and dust layer height
show a significant (95 % confidence level) day–night difference over the
major dust sources within the dust belt. Daytime DOD over the central to
northern Sahara, the central to eastern Arabian Peninsula, and the
Taklamakan Desert is significantly higher than that of nighttime but lower
than nighttime over the southern Sahel to the Guinea Coast and the western
to central Indian subcontinent in the annual mean. The magnitude of the
day–night differences in DOD is larger and more evident in boreal winter and
spring than in other seasons. The positive day–night differences in DOD (i.e.,
higher daytime values than nighttime) over the central Sahara, the Middle
East, and Asia are likely associated with greater dust emissions driven by
higher dust uplift potential (DUP) and stronger wind speeds during daytime. Dust layer heights demonstrate negative day–night differences over dust source
regions in the central Sahara, central Arabian Peninsula, and Taklamakan
Desert and positive height differences in the southern Sahel to the Guinea
Coast, southern parts of the Arabian Peninsula, and large parts of the
Indian subcontinent. The higher dust layer height over the Guinea Coast and
the Indian subcontinent during the daytime is associated with a deeper
planetary boundary layer height and greater convective instability during
daytime than nighttime, which promotes vertical transport and mixing of dust
aerosols. The corresponding lower daytime DOD over the Sahel and the Indian
subcontinent indicates a possible dilution of dust aerosols when they are
transported to higher altitudes by convection where they are more
susceptible to horizontal transport.</p>
<p>Ground-based observations of dust show surface PM<span class="inline-formula"><sub>10</sub></span> concentration and
CAOD exhibit a spatially varying diurnal cycle across the dust belt. CAOD
and PM<span class="inline-formula"><sub>10</sub></span> concentrations generally peak in late morning and from late
afternoon to midnight in the Sahel and in early afternoon and around early morning
in the Middle East, the timings of which are largely consistent with the
day–night differences in IASI DOD. It is also found that DOD from reanalysis
products (e.g., Modern-Era Retrospective Analysis for Research and
Applications, version 2 (MERRA-2) and ECMWF Atmospheric Composition
Reanalysis 4 (EAC4)) failed to capture the day–night differences in IASI DOD
in large parts of the dust belt except in small dust source hotspots over
North Africa.</p> |
| first_indexed | 2024-03-13T11:04:20Z |
| format | Article |
| id | doaj.art-4fa43ee4ead24f118e1e69a4232d4cab |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-03-13T11:04:20Z |
| publishDate | 2023-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-4fa43ee4ead24f118e1e69a4232d4cab2023-05-16T08:37:14ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242023-05-01235435546610.5194/acp-23-5435-2023Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and AsiaJ. Z. Tindan0J. Z. Tindan1Q. Jin2B. Pu3Department of Geography and Atmospheric Science, University of Kansas, Lawrence, KS, USAnow at: Department of Meteorology and Atmospheric Science, Pennsylvania State University, State College, PA, USADepartment of Geography and Atmospheric Science, University of Kansas, Lawrence, KS, USADepartment of Geography and Atmospheric Science, University of Kansas, Lawrence, KS, USA<p>Utilizing the well-calibrated, high-spectral-resolution equal-quality performance of daytime and nighttime (09:30 and 21:30 local solar Equator-crossing time (local solar ECT)) products of the Infrared Atmospheric Sounder Interferometer (IASI) from the Laboratoire de Météorologie Dynamique (LMD), this study investigates the day–night differences in dust aerosols over the global dust belt of North Africa, the Middle East, and Asia. Both daytime dust optical depth (DOD) and nighttime DOD at 10 <span class="inline-formula">µ</span>m show high consistency with solar and lunar observations of coarse-mode aerosol optical depth (CAOD) from AErosol RObotic NETwork (AERONET) sites across the dust belt, with correlation coefficients of 0.8–0.9 for most sites. Both IASI DOD and dust layer height show a significant (95 % confidence level) day–night difference over the major dust sources within the dust belt. Daytime DOD over the central to northern Sahara, the central to eastern Arabian Peninsula, and the Taklamakan Desert is significantly higher than that of nighttime but lower than nighttime over the southern Sahel to the Guinea Coast and the western to central Indian subcontinent in the annual mean. The magnitude of the day–night differences in DOD is larger and more evident in boreal winter and spring than in other seasons. The positive day–night differences in DOD (i.e., higher daytime values than nighttime) over the central Sahara, the Middle East, and Asia are likely associated with greater dust emissions driven by higher dust uplift potential (DUP) and stronger wind speeds during daytime. Dust layer heights demonstrate negative day–night differences over dust source regions in the central Sahara, central Arabian Peninsula, and Taklamakan Desert and positive height differences in the southern Sahel to the Guinea Coast, southern parts of the Arabian Peninsula, and large parts of the Indian subcontinent. The higher dust layer height over the Guinea Coast and the Indian subcontinent during the daytime is associated with a deeper planetary boundary layer height and greater convective instability during daytime than nighttime, which promotes vertical transport and mixing of dust aerosols. The corresponding lower daytime DOD over the Sahel and the Indian subcontinent indicates a possible dilution of dust aerosols when they are transported to higher altitudes by convection where they are more susceptible to horizontal transport.</p> <p>Ground-based observations of dust show surface PM<span class="inline-formula"><sub>10</sub></span> concentration and CAOD exhibit a spatially varying diurnal cycle across the dust belt. CAOD and PM<span class="inline-formula"><sub>10</sub></span> concentrations generally peak in late morning and from late afternoon to midnight in the Sahel and in early afternoon and around early morning in the Middle East, the timings of which are largely consistent with the day–night differences in IASI DOD. It is also found that DOD from reanalysis products (e.g., Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2) and ECMWF Atmospheric Composition Reanalysis 4 (EAC4)) failed to capture the day–night differences in IASI DOD in large parts of the dust belt except in small dust source hotspots over North Africa.</p>https://acp.copernicus.org/articles/23/5435/2023/acp-23-5435-2023.pdf |
| spellingShingle | J. Z. Tindan J. Z. Tindan Q. Jin B. Pu Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia Atmospheric Chemistry and Physics |
| title | Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia |
| title_full | Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia |
| title_fullStr | Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia |
| title_full_unstemmed | Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia |
| title_short | Understanding day–night differences in dust aerosols over the dust belt of North Africa, the Middle East, and Asia |
| title_sort | understanding day night differences in dust aerosols over the dust belt of north africa the middle east and asia |
| url | https://acp.copernicus.org/articles/23/5435/2023/acp-23-5435-2023.pdf |
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