Two pathways of how remote SST anomalies drive the interannual variability of autumnal haze days in the Beijing–Tianjin–Hebei region, China
<p>Analogous to the circumstances in wintertime, the increasing severity of autumnal haze pollution over the Beijing–Tianjin–Hebei (BTH) region may also lead to impairment of the socioeconomic development and human health in this region. Despite man-made aerosol emissions, the interannual vari...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/1521/2019/acp-19-1521-2019.pdf |
| Summary: | <p>Analogous to the circumstances in wintertime, the increasing
severity of autumnal haze pollution over the Beijing–Tianjin–Hebei (BTH)
region may also lead to impairment of the socioeconomic development and
human health in this region. Despite man-made aerosol emissions, the
interannual variability of autumnal (September–October–November) haze days
(AHDs) in the BTH region (AHD<span class="inline-formula"><sub>BTH</sub></span>) is apparently tied to the global and
regional meteorological anomalies. The present study suggests that an
above-normal AHD<span class="inline-formula"><sub>BTH</sub></span> is closely associated with the simultaneous sea
surface temperature (SST) warming in two regions (over the North Atlantic
subtropical sector, R1, and over the western North Pacific sector, R2).
When the autumnal SST warming in both R1 and R2 is significant, the
likelihood of a higher AHD<span class="inline-formula"><sub>BTH</sub></span> is greatly enhanced. Observational and
simulation evidence demonstrated how remote SST anomalies over R1 and R2
influence variation of AHD<span class="inline-formula"><sub>BTH</sub></span> via two different pathways. Firstly, SST
warming in R1 can induce a downstream midlatitudinal Rossby wave train,
leading to a barotropic high-pressure and subsidence anomaly over the BTH
region. Secondly, SST warming in R2 can also result in air subsidence over
the BTH region through an anomalous local meridional cell. Through these two
distinct pathways, localized meteorological circumstances conducive to a
higher AHD<span class="inline-formula"><sub>BTH</sub></span> (i.e., repressed planetary boundary layer, weak southerly
airflow, and warm and moist conditions) can be established.</p> |
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| ISSN: | 1680-7316 1680-7324 |