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Webinar: Influence of emission reduction on marine low clouds over global oceans in recent two decades
Wednesday, 19 January 2022, 7:00
Wednesday, January 19, 2022. 7:00 PM. Webinar: Influence of emission reduction on marine low clouds over global oceans in recent two decades. Minghuai Wang, Nanjing University. Sponsored by NOAA Chemical Sciences Laboratory Seminar Series. More information here. Register here.
Abstract: Decadal-scale trends in aerosol and cloud properties provide important ways for understanding aerosol-cloud interactions. Here we analyze synergetic long-term trends in aerosol properties and cloud properties over the global ocean using MODIS products over the recent two decades. Cloud droplet number concentration (CDNC) and aerosol parameters show a consistent decreasing trend over the East Coast of the United States (EUS), west coast of Europe (WEU), and east coast of China (EC) due to emission reduction over recent decades. Emission reduction has lowered the hemispheric contrast of cloud droplet number concentration by more than 50% in the recent two decades. Over regions with significant long-term trends of aerosol loading and CDNC (e.g., EUS and WEU), the sensitivity of CDNC to aerosol loading based on the long-term trend is closer to those derived from ground and aircraft observations and larger than those derived from instantaneous satellite observations, providing an alternative way for quantifying aerosol-cloud interactions. Our further analysis over the East Coast of the United States reveals that, while the observed annual-mean cloud fraction shows no significant trend, this is due to the cancellation from the opposite trends in CDNC and relative humidity. A multivariate regression model revealed that the decline in CDNC alone would lead to about 20% relative decline in cloud fraction, indicating the significant aerosol effects on cloud fraction. Satellite observations are further compared with results from climate models.
Bio(s): Minghuai Wangthis link opens in a new window is the Head of the Department of Atmospheric Physics at Nanjing University, and the Director of Nanjing University's Joint International Research Laboratory of Atmospheric and Earth System Sciences. His research focuses on aerosol and cloud modeling, aerosol-cloud interactions, and multi-scale modeling. Prof. Wang received his MS in Atmospheric Science from Peking University, Beijing, China, and his PhD in Atmospheric Science from the University of Michigan, Ann Arbor. In his PhD work he studied aerosol-cloud interactions and cirrus clouds using global simulations. In 2009, Dr. Wang joined the Pacific Northwest National Laboratory, where he worked on global aerosol and cloud simulations, as well as on satellite analysis of aerosol-cloud interactions. Dr. Wang joined Nanjing University as a professor in 2014. He serves as the co-chair of the Aerosol, Clouds, Precipitation and Climate (ACPC) Initiative, as an Editor of Advances in Atmospheric Sciences, and as an Associate Editor of the Journal of Geophysical Research (Atmospheres).