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Anomalous high ozone in the Pearl River Delta, China in 2019: A cause attribution analysis
https://orcid.org/0000-0002-0239-1354
Abstract Surface ozone (O3) pollution in the Pearl River Delta (PRD), especially persistent O3 pollution episodes lasting three days or longer (OPE3), showed an anomalous peak during the autumn of 2019 (bulge-2019). Our research reveals a robust connection between the occurrence of OPE3 events and days with low cloud cover. Specifically, low-cloud days comprised 55% of the total number of OPE3 events in the PRD during the autumn season spanning from 2015 to 2021. Notably, as much as 74% of the bulge-2019 is related to low-cloud days. However, establishing a direct causal link remains challenging. In autumn 2019, an anomalous cyclonic center developed over the Philippine Sea, with anomalous northerly winds on its northwestern flank, leading to anomalous downdraft over South China. This pattern was characterized by stagnant, low relative humidity, intensified solar radiation, and low cloud cover conditions that were conducive to the photochemical formation and accumulation of O3. Further analysis of the relationship between low-cloud days and El Niño–Southern Oscillation shows that eastern Pacific El Niño events are associated with fewer low-cloud days in the PRD in autumn, whereas central Pacific (CP) El Niño events result in more low-cloud days. In addition, the anomalous cyclonic center over the Philippine Sea serves as the crucial atmospheric circulation system connecting CP El Niño and high O3 level over southern China. Therefore, we propose that the increased downdraft of PRD brought by northward tropical cyclones (TCs) during more low-cloud days in 2019 is highly likely the primary cause of the occurrence of the bulge-2019.
Highlights Low-cloud days comprised 55% of PRD OPE3 events in 2015–2021 autumn, specially reaching 74% in 2019. The anomalous cyclonic center over the Philippine Sea notably controlled PRD's autumn 2019 O3 levels. Increased downdrafts by northward tropical cyclones in low-cloud days might have caused the 2019 bulge in O3 levels in PRD.
Anomalous high ozone in the Pearl River Delta, China in 2019: A cause attribution analysis
https://orcid.org/0000-0002-0239-1354
Abstract Surface ozone (O3) pollution in the Pearl River Delta (PRD), especially persistent O3 pollution episodes lasting three days or longer (OPE3), showed an anomalous peak during the autumn of 2019 (bulge-2019). Our research reveals a robust connection between the occurrence of OPE3 events and days with low cloud cover. Specifically, low-cloud days comprised 55% of the total number of OPE3 events in the PRD during the autumn season spanning from 2015 to 2021. Notably, as much as 74% of the bulge-2019 is related to low-cloud days. However, establishing a direct causal link remains challenging. In autumn 2019, an anomalous cyclonic center developed over the Philippine Sea, with anomalous northerly winds on its northwestern flank, leading to anomalous downdraft over South China. This pattern was characterized by stagnant, low relative humidity, intensified solar radiation, and low cloud cover conditions that were conducive to the photochemical formation and accumulation of O3. Further analysis of the relationship between low-cloud days and El Niño–Southern Oscillation shows that eastern Pacific El Niño events are associated with fewer low-cloud days in the PRD in autumn, whereas central Pacific (CP) El Niño events result in more low-cloud days. In addition, the anomalous cyclonic center over the Philippine Sea serves as the crucial atmospheric circulation system connecting CP El Niño and high O3 level over southern China. Therefore, we propose that the increased downdraft of PRD brought by northward tropical cyclones (TCs) during more low-cloud days in 2019 is highly likely the primary cause of the occurrence of the bulge-2019.
Highlights Low-cloud days comprised 55% of PRD OPE3 events in 2015–2021 autumn, specially reaching 74% in 2019. The anomalous cyclonic center over the Philippine Sea notably controlled PRD's autumn 2019 O3 levels. Increased downdrafts by northward tropical cyclones in low-cloud days might have caused the 2019 bulge in O3 levels in PRD.
Anomalous high ozone in the Pearl River Delta, China in 2019: A cause attribution analysis
https://orcid.org/0000-0002-0239-1354
Abstract Surface ozone (O3) pollution in the Pearl River Delta (PRD), especially persistent O3 pollution episodes lasting three days or longer (OPE3), showed an anomalous peak during the autumn of 2019 (bulge-2019). Our research reveals a robust connection between the occurrence of OPE3 events and days with low cloud cover. Specifically, low-cloud days comprised 55% of the total number of OPE3 events in the PRD during the autumn season spanning from 2015 to 2021. Notably, as much as 74% of the bulge-2019 is related to low-cloud days. However, establishing a direct causal link remains challenging. In autumn 2019, an anomalous cyclonic center developed over the Philippine Sea, with anomalous northerly winds on its northwestern flank, leading to anomalous downdraft over South China. This pattern was characterized by stagnant, low relative humidity, intensified solar radiation, and low cloud cover conditions that were conducive to the photochemical formation and accumulation of O3. Further analysis of the relationship between low-cloud days and El Niño–Southern Oscillation shows that eastern Pacific El Niño events are associated with fewer low-cloud days in the PRD in autumn, whereas central Pacific (CP) El Niño events result in more low-cloud days. In addition, the anomalous cyclonic center over the Philippine Sea serves as the crucial atmospheric circulation system connecting CP El Niño and high O3 level over southern China. Therefore, we propose that the increased downdraft of PRD brought by northward tropical cyclones (TCs) during more low-cloud days in 2019 is highly likely the primary cause of the occurrence of the bulge-2019.
Highlights Low-cloud days comprised 55% of PRD OPE3 events in 2015–2021 autumn, specially reaching 74% in 2019. The anomalous cyclonic center over the Philippine Sea notably controlled PRD's autumn 2019 O3 levels. Increased downdrafts by northward tropical cyclones in low-cloud days might have caused the 2019 bulge in O3 levels in PRD.
Anomalous high ozone in the Pearl River Delta, China in 2019: A cause attribution analysis
Wu, Yanxing (Autor:in) / Liu, Run (Autor:in) / Xu, Jianmin (Autor:in) / Hu, Wenzhao (Autor:in) / Liu, Shaw Chen (Autor:in)
Atmospheric Environment ; 319
02.12.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Photochemical indicators of ozone sensitivity: application in the Pearl River Delta, China
| Springer Verlag | 2016
The Pearl River Delta, South China, 1979 - Back
Online Contents | 2003
The Pearl River Delta, South China, 2003 - Front
Online Contents | 2003