Title: Analysis of Data from Recent Airborne Field Campaigns to Inform on Impact of Clouds on Weather and Climate
Lecturer: Prof. Greg McFarquhar (University of Oklahoma, USA)
Time: Friday May 23, 2025 at 10:30 AM
Venue: Lecture Hall D103, School of Atmospheric Sciences
Abstract: The most fundamental and complex problems in climate and weather research today are our poor understanding of the basic properties of clouds and our inability to determine quantitatively the many effects that cloud processes have on weather and climate. During a previous seminar (2019) at Nanjing the use of aircraft cloud microphysical observations for quantifying ice cloud microphysical properties, processes, and their uncertainties were discussed. In this talk, three specific examples of the use of cloud observations for learning about the role of cloud processes in weather will be discussed. First, observations collected during the 2020, 2022 and 2023 NASA-funded Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) project will be discussed. The use of in-situ and remote sensing data to characterize and understand banding features in winter snowstorms will be illustrated, examining the role of small-scale generating cells that are typically 1 to 2 km deep, 0.5 to 2 km wide, and with updrafts of 1 to 2 m s-1 in generating protective environments for enhanced particle growth. Second, the NSF-funded 2022 Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) obtained in-situ and remote sensing aircraft observations in coordination with high-resolution ground-based radar observations to study the influences of aerosols and meteorological conditions on the evolution of isolated convective cells. Using in-situ penetrations of over 300 intense convective cores and machine learning, the environmental conditions having the most influence on core microphysical properties are identified and the potential of aerosols causing condensational invigoration is examined. Third, the 2024 Cold-Air outbreak Experiment in the Sub-Arctic Region (CAESAR) field campaign sampled cold air outbreaks as they traversed the Norwegian Sea from the ice edge to the coast of Sweden. Vertical profiles of cloud properties and their dependence on environmental conditions are quantified in order to better understand processes occurring in boundary layer clouds over the Ocean. In summary, comments on the need for a common framework and standardized processing for better understanding processes affecting the evolution of clouds are made.
Brief introduction to the speaker: Greg McFarquhar received his B.Sc. from the University of Toronto in Mathematics and Physics, and his M.Sc. and Ph.D. from the University of Toronto in atmospheric physics. He spent two years as a postdoctoral fellow at the Scripps Institute of Oceanography in La Jolla, CA, and subsequently worked at the National Center for Atmospheric Research in Boulder, CO, and the University of Illinois in Urbana-Champaign before joining the University of Oklahoma in 2017. He currently serves as a Professor in the School of Meteorology and Director of the Cooperative Institute for Severe and High Impact Weather Research and Operations (CIWRO) at the University of Oklahoma. He is president of the International Commission on Clouds and Precipitation (ICCP), chief editor of the American Meteorological Society Monograph Collection, editor for Atmospheric Chemistry and Physics, and associate editor for the Quarterly Journal of the Royal Meteorological Society. He has 250 publications in the refereed literature, an h-index of 71, and he and his group have made over 825 presentations at conferences and working group meetings. He has participated in or led 36 different air- or ship-based cloud measurement field campaigns. He is a fellow of the American Meteorological Society and the American Geophysical Union.