报告人: Xian Lu
Antarctica is a unique laboratory to study neutral dynamics because the strong and persistent winter-time polar night jet (30—50 km) provides the seed to generate a rich and broad spectrum of atmospheric waves, such as the persistent and strong planetary waves (PWs) in the stratosphere. The generation mechanism and vertical coupling of these PWs from the stratosphere to the lower thermosphere are simulated by two mechanistic models, and possible mechanisms are proposed to explain their significant growth and impacts above 100 km.
During a geomagnetic storm characterized by a coronal mass ejection (CME) event, a neutral temperature inversion layer was observed near 130 km, with a temperature enhancement of 500—600 K at the peak altitude. Such a temperature structure is missing in the general circulation models (CTIPe and TIE-GCM). By comparing the model simulations of electric fields and ionization rate with SuperDARN and DMSP, we estimate the underestimations of these variables in the models. The impacts of mean electric fields and their variabilities, and ionizaration rate on Joule heating and neutral temperature are studied by performing the test runs in the models. We find all these factors could work together to give the observed neutral temperature inversion layer and enhancement.
Dr. Lu will also introduce the PhD program at Clemson University, especially the openings for graduate students and postdocs.
Dr. Xian Lu got her PhD degree from the Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign (UIUC) in 2011. She is now an assistant professor in the Department of Physics and Astronomy at Clemson University, and the leader of the whole atmospheric modeling and observation group. Her group has been running 3 whole atmosphere models and 4 mechanistic models. She is the principal investigator (PI) and Co-I of 3 NSF- and NASA-funded projects and the PI of 1 project funded by Clemson. She has published more than 25 papers in peer-reviewed journals and given more than 70 presentations at international conferences. She has been frequently invited to serve as a reviewer for more than 10 renowned journals including GRL, JGR, JAS, JASTP, AG and etc. She is a frequent reviewer for the NSF, NASA, and United States-Israel Binational Science Foundation (BSF) proposals and also served the panel for these funding agencies. From November 2015 to January 2016, she was working at the McMurdo station, Antarctica on the operation and data collection of the Fe Boltzmann lidar. She has been advising graduate and undergraduate students on the study of atmospheric sciences and space physics since 2012. Her group currently has 1 postdoc, 2 undergraduates, with another 1 postdoc and 1 graduate student being expected in this Fall. Dr. Lu’s main research interests include using numerical modeling and observations to study neutral atmospheric dynamics and electrodynamics, space weather, and magnetosphere-ionosphere-thermosphere coupling.