15-year variability of desert dust optical depth on global and regional scales
<p>This study aims to investigate global, regional and seasonal temporal dust changes as well as the effect of dust particles on total aerosol loading using the ModIs Dust AeroSol (MIDAS) fine-resolution dataset. MIDAS delivers dust optical depth (DOD) at fine spatial resolution (<span clas...
Guardado en:
| Autores principales: | , , , , , |
|---|---|
| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
|
| Materias: | |
| Acceso en línea: | https://doaj.org/article/f45c2195c9cd4fcfb8084830529a174d |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| Sumario: | <p>This study aims to investigate global, regional and
seasonal temporal dust changes as well as the effect of dust particles on
total aerosol loading using the ModIs Dust AeroSol (MIDAS) fine-resolution dataset. MIDAS delivers dust optical depth (DOD) at fine spatial resolution
(<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">0.1</mn><msup><mi/><mo>∘</mo></msup><mo>×</mo><mn mathvariant="normal">0.1</mn><msup><mi/><mo>∘</mo></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="52pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="9ff7f6b7ad74ef28cb0ca0c82ba5867a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-16499-2021-ie00001.svg" width="52pt" height="11pt" src="acp-21-16499-2021-ie00001.png"/></svg:svg></span></span>) spanning from 2003 to 2017. Within this
study period, the dust burden increased across the central Sahara (up
to 0.023 yr<span class="inline-formula"><sup>−1</sup></span>) and Arabian Peninsula (up to 0.024 yr<span class="inline-formula"><sup>−1</sup></span>). Both
regions observed their highest seasonal trends in summer (up to 0.031 yr<span class="inline-formula"><sup>−1</sup></span>). On the other hand, declining DOD trends are encountered in the
western (down to <span class="inline-formula">−0.015</span> yr<span class="inline-formula"><sup>−1</sup></span>) and eastern (down to <span class="inline-formula">−0.023</span> yr<span class="inline-formula"><sup>−1</sup></span>) Sahara, the Bodélé Depression (down to <span class="inline-formula">−0.021</span> yr<span class="inline-formula"><sup>−1</sup></span>), the Thar
(down to <span class="inline-formula">−0.017</span> yr<span class="inline-formula"><sup>−1</sup></span>) and Gobi (down to <span class="inline-formula">−0.011</span> yr<span class="inline-formula"><sup>−1</sup></span>) deserts, and the
Mediterranean Basin (down to <span class="inline-formula">−0.009</span> yr<span class="inline-formula"><sup>−1</sup></span>). In spring, the most
negative seasonal trends are recorded in the Bodélé Depression (down to
<span class="inline-formula">−0.038</span> yr<span class="inline-formula"><sup>−1</sup></span>) and Gobi Desert (down to <span class="inline-formula">−0.023</span> yr<span class="inline-formula"><sup>−1</sup></span>), whereas they are in the
western (down to <span class="inline-formula">−0.028</span> yr<span class="inline-formula"><sup>−1</sup></span>) and the eastern Sahara (down to <span class="inline-formula">−0.020</span> yr<span class="inline-formula"><sup>−1</sup></span>) and the Thar Desert (down to <span class="inline-formula">−0.047</span> yr<span class="inline-formula"><sup>−1</sup></span>) in summer. Over the
western and eastern sector of the Mediterranean Basin, the most negative
seasonal trends are computed at summer (down to <span class="inline-formula">−0.010</span> yr<span class="inline-formula"><sup>−1</sup></span>) and
spring (down to <span class="inline-formula">−0.006</span> yr<span class="inline-formula"><sup>−1</sup></span>), respectively. The effect of DOD on the
total aerosol optical depth (AOD) change is determined by calculating the
DOD-to-AOD trend ratio. Over the Sahara the median ratio values range
from 0.83 to 0.95, whereas in other dust-affected areas (Arabian Peninsula,
southern Mediterranean, Thar and Gobi deserts) the ratio value is approximately
0.6. In addition, a comprehensive analysis of the factors affecting the
sign, the magnitude and the statistical significance of the calculated
trends is conducted. Firstly, the implications of the implementation of the
geometric mean instead of the arithmetic mean for trend calculations are
discussed, revealing that the arithmetic-based trends tend to overestimate
compared to the geometric-based trends over both land and ocean. Secondly,
an analysis interpreting the differences in trend calculations under
different spatial resolutions (fine and coarse) and time intervals is
conducted.</p> |
|---|