Threading the Atmosphere and the Space Environment: Global Effects by Small Scale Gravity Waves

Hanli Liu, High Altitude Observatory, 

National Center for Atmospheric Research

Video Recording

Slides

Abstract:
Atmospheric gravity waves are buoyancy waves that are excited by meteorological processes, such as deep convection, tropical cyclones, jet streams, and flow over topography. These waves become dynamically important, or even dominant, at the Earth's upper atmosphere and in its space environment. This is because of their global distribution, their exponential growth with altitudes as the air density decreases, and their contribution to the momentum and energy budgets. They are therefore thought to play a key role in connecting the terrestrial atmosphere with the space environment. However, it has been challenging for observations and numerical models alike to quantify their global effects because of the large scale range--from km to global scale--required to resolve them in a whole atmosphere context. In this talk, I will discuss our recent efforts to address this challenge by developing the high-resolution Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). WACCM-X is one of the atmosphere components of the NCAR’s Community Earth System Model (CESM). It is a first-principle model that simulates processes from the Earth surface to the upper thermosphere, including radiative, physical, chemical, dynamical, and electrodynamical processes. With this newly developed capability, we can now assess the wave effects on the circulation, transport and composition of the whole atmosphere system. At the same time, the high-resolution simulations also reveal the importance of unresolved, smaller scale waves in the global momentum budget. We will explore innovative ways to account for such wave impacts. 

 

Bio:
Dr. Hanli Liu is a senior scientist at the High Altitude Observatory, National Center for Atmospheric Research. He received a B.S. in Fluid Mechanics from the University of Science and Technology of China, and a Ph.D. in Atmospheric and Space Physics from the University of Michigan. He came to the Observatory in 1997 as a postdoctoral researcher, and joined the scientific staff in 1999. His research includes: theoretical, numerical, and interpretive studies of the dynamics, structure, and variability of the Earth's middle and upper atmosphere; coupling of different atmospheric regions on global and regional scales, including impacts of lower atmospheric forcing on space weather; atmospheric waves and geophysical turbulence. He is leading the thermosphere/ionosphere extension of the Whole Atmosphere Community Climate Model (WACCM-X).

Summary: