报告题目：Coupling between the lower and upper atmosphere via the convectively generated gravity waves ----From severe weather to space weather 

　　报告人：乐加，Hampton University，Research assistant Professor 

　　时间：3月10日 9:30 

　　地点：武汉物数所综合楼7楼会议室 

　　摘要： 

　　Atmospheric gravity waves or buoyancy waves have restoring force of gravity or buoyancy. Gravity waves are excited when an air parcel is displaced to a region with a different density. In the Earth’s atmosphere, gravity waves are one mechanism for the transfer of momentum from the troposphere to the stratosphere and up. In this talk, we combine various techniques to reveal a more complete picture of concentric convectively-excited gravity waves simultaneously in the stratosphere and mesosphere. The ground-based instrument used is an OH all-sky imager in Colorado. Three nadir-viewing instruments on NASA satellites are the Atmospheric Infrared Sounder (AIRS) on Aqua, Cloud Imaging and Particle Size (CIPS) on the Aeronomy of Ice in the Mesosphere (AIM) and the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP satellites. The third instrument, the Day/Night Band Imager on VIIRS, measures the broadband airglow emissions directly or reflected back by clouds. We will present the observations of gravity waves observed in the upper atmosphere over various severe weather systems, such as devastating tornados, hurricanes, tropical cyclones, thunderstorms, Super Typhoon Haiyan, etc. The modulation of the ionospheric electron density by upward propagating concentric gravity waves will also be introduced. 

　　Spaceborne VIIRS Day/Night Band Reveals Nightglow waves over tropical Cyclone Mahasen