A203-10
Trends of Surface and Tropospheric Ozone over Southeast Asia and their drivers during 2005 to 2014

Tuesday, 15 December 2020: 18:24
Virtual
Xiaolin Wang1, Tzung-May Fu1, Lin Zhang2, Xiao Lu2, Xiong Liu3, Teerachai Amnuaylojaroen4, Mohd Talib Latif5, Yaping Ma1, Lijuan Zhang2 and Xu Feng2, (1)Peking University, Beijing, China, (2)Peking University, Department of Atmospheric and Oceanic Sciences, Beijing, China, (3)Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States, (4)University of Phayao, Phayao, Thailand, (5)Universiti Kebangsaan Malaysia, School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Bangi, Malaysia
Recorded Presentation
Abstract:
Several analyses have indicated increases in tropospheric ozone over different parts of Southeast Asia (SEA) during recent decades, which have important implications for human and ecosystem health, food security, and regional climate. Here, we combined ozone measurements from surface sites, aircrafts, soundings, and satellites, as well as simulations using the GEOS-Chem chemical transport model, to assess the trends of seasonal surface and tropospheric ozone over SEA during 2005 to 2014. We found that surface ozone had significantly increased over the Peninsular Southeast Asia (PSEA) in all seasons at rates of 0.9 to 1.5 ppb yr-1. Over the Malaysian Peninsula, surface ozone had increased during June to November at rates of 0.25 to 0.54 ppb yr-1. Surface ozone measured at the one available surface site in Indonesia showed no significant changes during March to August but showed slight decreases during September to February. Observations from the Ozone Monitoring Instrument showed that the tropospheric ozone column concentrations over PSEA and Maritime continent (MC) had increased significantly in MAM and SON, while the changes in JJA and DJF were small. Sensitivity simulations using the GEOS-Chem model showed that the increases in surface ozone over PSEA were largely driven by the growing anthropogenic emissions from both within the PSEA (45.7±9.4%) and outside the SEA region (25.8±4.1%). Increases of surface ozone over Indonesia were mainly driven by growing local anthropogenic emissions (79.4±10.1%). The increases of tropospheric ozone changes over the PSEA were due to a combination of factors, including the interannual variability of meteorology (5.9±52.2%), and changes in anthropogenic emissions both outside (25.3±19.8%) and within the SEA (25.1±8.3%). In contrast, the interannual variation of meteorology (41.9±11.6%) and increases in local anthropogenic emissions (42.3±11.0%) drove the increases of tropospheric ozone in MC.
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