This study analyzed the nature, mechanisms and drivers for Hot-and-Polluted episodes (HPEs) in the Pearl River Delta, China. A total of eight HPEs were identified and can be grouped into three clusters of HPEs that were respectively driven (1) by weak subsidence and convection induced by approaching tropical cyclones, (2) by calm conditions with low wind speed at the lower atmosphere, and (3) by the combination of both aforementioned conditions.
This study analyzed the nature, mechanisms and drivers for Hot-and-Polluted episodes (HPEs) in...
Review status: this preprint is currently under review for the journal ACP.
Characteristics of surface energy balance and atmospheric
circulation during hot-and-polluted episodes and their synergistic
relationships with urban heat islands over the Pearl River Delta
region
Ifeanyichukwu C. Nduka1,Steve Hung Lam Yim1,2,Chi-Yung Tam3,and Jianping Guo4Ifeanyichukwu C. Nduka et al.Ifeanyichukwu C. Nduka1,Steve Hung Lam Yim1,2,Chi-Yung Tam3,and Jianping Guo4
Received: 13 Oct 2020 – Accepted for review: 03 Dec 2020 – Discussion started: 08 Dec 2020
Abstract. This study analyzed the nature, mechanisms and drivers for Hot-and-Polluted episodes (HPEs) in the Pearl River Delta, China. Numerical model simulations were conducted for summer and autumn of 2009–2011. A total of eight HPEs were identified, mainly happening in August and September. K-means clustering was applied to group the HPEs into three clusters based on their characteristics and mechanism. We found three HPEs were driven by weak subsidence and convection induced by approaching tropical cyclones (TC-HPE), two HPEs was controlled by calm conditions (ST-HPE) with low wind speed at the lower atmosphere, whereas the remaining three HPEs were driven by the combination of both aforementioned systems (HY-HPE). TC-HPE and ST-HPE had both positive synergistic effect between HPE and UHI (~1.1 °C increase); whereas no discernible synergistic effect was found in HY-HPE. Total aerosol radiative forcing (TARF) caused a reduction in temperature (0.5–1.0 °C) in TC-HPE and ST-HPE, but an increase (0.5 °C) in HY-HPE.
This study analyzed the nature, mechanisms and drivers for Hot-and-Polluted episodes (HPEs) in the Pearl River Delta, China. A total of eight HPEs were identified and can be grouped into three clusters of HPEs that were respectively driven (1) by weak subsidence and convection induced by approaching tropical cyclones, (2) by calm conditions with low wind speed at the lower atmosphere, and (3) by the combination of both aforementioned conditions.
This study analyzed the nature, mechanisms and drivers for Hot-and-Polluted episodes (HPEs) in...