Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current

Abstract Meteorological factors can result in air pollution. Some studies have indicated that the leeward side effect’s weak flow and subsidence play major roles in inducing high PM10 (particulate matter with a diameter of ≤ 10 µm) in southern Taiwan during winter due to topographic blocking. Howeve...

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Main Authors: Wei-Kuo Soong, Chung-Hsuang Hung
Format: Article
Language:English
Published: Springer 2024-07-01
Series:Aerosol and Air Quality Research
Subjects:
Online Access:https://doi.org/10.4209/aaqr.240015
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author Wei-Kuo Soong
Chung-Hsuang Hung
author_facet Wei-Kuo Soong
Chung-Hsuang Hung
author_sort Wei-Kuo Soong
collection DOAJ
description Abstract Meteorological factors can result in air pollution. Some studies have indicated that the leeward side effect’s weak flow and subsidence play major roles in inducing high PM10 (particulate matter with a diameter of ≤ 10 µm) in southern Taiwan during winter due to topographic blocking. However, the results of this research showed that the rapid build-up of high PM10 in Kaohsiung city (KHC) during evenings is not completely explained by weak flow and subsidence. In northern Taiwan, topographic blocking on northwesterly enhances a significant pressure gradient force (PGF) induced strong winds. According to the Froude number (above 0.5), the flow in northern Taiwan can pass the terrain, producing subsidence warming in central Taiwan, which is located at the leeward side of the northeastern Central Mountain Range (CMR). In addition, strong winds blew river dusts in the middle of Taiwan under a stable atmosphere and stimulated density current, transporting PM10 to southern Taiwan. A large horizontal pressure gradient was still formed in central western Taiwan between the cold flow originating from northern Taiwan and the warm flow by subsidence warming. The strong PGF and the interaction between the flow and the terrain in northern Taiwan should favor the density current. After PM10 was transported into KHC efficiently in a short time by the density current, the local effect of weak rear flow and subsidence in KHC enhanced and maintained PM even more than it did in central Taiwan.
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2071-1409
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series Aerosol and Air Quality Research
spelling doaj-art-b29e6cd590d94b16bdafec8ff71cb2292025-02-09T12:24:33ZengSpringerAerosol and Air Quality Research1680-85842071-14092024-07-0124912110.4209/aaqr.240015Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density CurrentWei-Kuo Soong0Chung-Hsuang Hung1Department of Military Meteorology, Air Force Institute of TechnologyDepartment of Safety Health and Environmental Engineering, National Kaohsiung University of Science and TechnologyAbstract Meteorological factors can result in air pollution. Some studies have indicated that the leeward side effect’s weak flow and subsidence play major roles in inducing high PM10 (particulate matter with a diameter of ≤ 10 µm) in southern Taiwan during winter due to topographic blocking. However, the results of this research showed that the rapid build-up of high PM10 in Kaohsiung city (KHC) during evenings is not completely explained by weak flow and subsidence. In northern Taiwan, topographic blocking on northwesterly enhances a significant pressure gradient force (PGF) induced strong winds. According to the Froude number (above 0.5), the flow in northern Taiwan can pass the terrain, producing subsidence warming in central Taiwan, which is located at the leeward side of the northeastern Central Mountain Range (CMR). In addition, strong winds blew river dusts in the middle of Taiwan under a stable atmosphere and stimulated density current, transporting PM10 to southern Taiwan. A large horizontal pressure gradient was still formed in central western Taiwan between the cold flow originating from northern Taiwan and the warm flow by subsidence warming. The strong PGF and the interaction between the flow and the terrain in northern Taiwan should favor the density current. After PM10 was transported into KHC efficiently in a short time by the density current, the local effect of weak rear flow and subsidence in KHC enhanced and maintained PM even more than it did in central Taiwan.https://doi.org/10.4209/aaqr.240015PM10Density currentInversionPressure gradient force
spellingShingle Wei-Kuo Soong
Chung-Hsuang Hung
Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
Aerosol and Air Quality Research
PM10
Density current
Inversion
Pressure gradient force
title Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
title_full Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
title_fullStr Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
title_full_unstemmed Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
title_short Rapid Built-up of PM10 in the Ambient Air of the Leeward Side Resulting from Strong Pressure Gradient Force Associated with Density Current
title_sort rapid built up of pm10 in the ambient air of the leeward side resulting from strong pressure gradient force associated with density current
topic PM10
Density current
Inversion
Pressure gradient force
url https://doi.org/10.4209/aaqr.240015
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AT chunghsuanghung rapidbuiltupofpm10intheambientairoftheleewardsideresultingfromstrongpressuregradientforceassociatedwithdensitycurrent