Intraseasonal variation of the northeast Asian anomalous anticyclone and its impacts on PM<sub>2.5</sub> pollution in the North China Plain in early winter
<p>The canonical view of the northeast Asian anomalous anticyclone (NAAA) is a crucial factor for determining poor air quality (i.e., higher particulate matter, PM<span class="inline-formula"><sub>2.5</sub></span> concentrations) in the North China Plain (NCP)...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/6507/2022/acp-22-6507-2022.pdf |
| Summary: | <p>The canonical view of the northeast Asian anomalous anticyclone (NAAA) is a crucial factor for determining poor air quality (i.e., higher particulate matter, PM<span class="inline-formula"><sub>2.5</sub></span> concentrations) in the North China Plain (NCP) on
the interannual timescale. However, there is considerable intraseasonal
variability in the NAAA in early winter (November–January), and the
corresponding mechanism of its impacts on PM<span class="inline-formula"><sub>2.5</sub></span> pollution in the NCP is
not well understood. Here, we find that the intraseasonal NAAA usually
establishes quickly on day 3 prior to its peak day with a duration of 8 d, and its evolution is closely tied to the Rossby wave from upstream
(i.e., the North Atlantic). Moreover, we find that the NAAA with a westward
tilt might be mainly related to the wavenumbers 3–4. Further results
reveal that against this background, the probability of regional PM<span class="inline-formula"><sub>2.5</sub></span>
pollution for at least 3 d in the NCP is as high as 69 % (80 % at
least 2 d) in the Nov–Jan (NDJ) period 2000–2021. In particular, air quality in the
NCP tends to deteriorate on day 2 prior to the peak day and reaches a peak
on the next day with a life cycle of 4 d. In the course of PM<span class="inline-formula"><sub>2.5</sub></span>
pollution, a shallower atmospheric boundary layer and stronger surface
southerly wind anomaly associated with the NAAA in the NCP appear 1 d
earlier than poor air quality, which provides dynamic and thermal conditions
for the accumulation of pollutants and finally occurrence of the PM<span class="inline-formula"><sub>2.5</sub></span>
pollution on the following day. Furthermore, we show that the stagnant air
leading to poor air quality is determined by the special structure of
temperature in the vertical direction of the NAAA, while weak ventilation
conditions might be related to a rapid build-up of the NAAA. The present
results quantify the impact of the NAAA on PM<span class="inline-formula"><sub>2.5</sub></span> pollution in the NCP
on the intraseasonal timescale.</p> |
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| ISSN: | 1680-7316 1680-7324 |