Dynamical Characteristics of Inertia-Gravity Waves in the Antarctic Mesosphere

This book examines the origins and dynamical characteristics of atmospheric inertia-gravity waves in the Antarctic mesosphere. Gravity waves are relatively small-scale atmospheric waves with a restoring force of buoyancy that can transport momentum upward from the troposphere to the middle atmosphere. In previous studies, the dynamical characteristics of mesospheric gravity waves have not been fully examined using numerical simulations, since performing a numerical simulation with a high resolution and a high model-top requires considerable computational power. However, recent advances in computational capabilities have allowed us to perform numerical simulations using atmospheric general circulation models, which cover the troposphere to the mesosphere with a sufficiently fine horizontal resolution to resolve small-scale gravity waves. The book first describes the simulation of mesospheric gravity waves using a high-resolution non-hydrostatic atmospheric model with a high model top. The accuracy of the numerical results was confirmed by the first Mesosphere-Stratosphere-Troposphere/Incoherent Scattering (MST/IS) radar observation in the Antarctic. It also depicts the origins and propagation processes of mesospheric gravity waves on the basis of the results of the high-resolution numerical model. The behaviors of mesospheric gravity waves can be clearly explained using both fundamental and cutting-edge theories of fluid dynamics

Auteur

Ryosuke Shibuya is a Postdoctoral Researcher in the Project Team for HPC Advanced Predictions utilizing Big Data Research Unit for Predictability of Global Weather Extremes, Japan Agency for Marine-Earth Science and Technology (JAMSTEC). He received his B.Sc., M.Sc. and Ph.D. from the University of Tokyo in March 2012, March 2014, and October 2017, respectively. He was awarded the Japan Society for Promotion of Science (JSPS) research fellowship for young scientists, and his research throughout his doctoral program was supported by the JSPS. He has also received a number of prizes and awards: the School of Science Research Award (Master) from the University of Tokyo in 2014, the best student oral presentation award at the American Meteorological Society's 21th Symposium in 2014, and the School of Science Research Award (Ph.D.) from the University of Tokyo in 2017.

Contenu
AbstractContents
List of Figure captionsList of Table captions1. General Introduction1.1 Dynamical properties of gravity waves1.2 Gravity waves in the Antarctic1.3 Observational and modeling studies of the mesospheric gravity waves in the Antarctic1.4 The Purpose of this study2. A new transformation method for a quasi-uniform and fine grid system in a circular region using the spring dynamics2.1 A short review for the previous stretched grid systems2.2 A standard grid generation method in NICAM2.2.1 Icosahedral grid on a sphere2.2.2 Spring dynamics2.3How to determine the characteristic spring length2.3.1 A constraint on the cell area and total grid number over the sphere2.3.2 Connection with the Schmidt transformation2.3.3 The mathematical constraints on 0, n, and 2.4. Results: Grid properties2.4.1 Resolution2.4.2 Smoothness and Isotropy2.4.3 Numerical simulation2.5 Summary and concluding remarks3. Quasi-12 h inertia-gravity waves in the lower mesosphere observed by the PANSY radar at Syowa Station (39.6°E, 69.0 °S)3.1 A review for dominant mesospheric disturbances3.2 Methodology3.2.1 The PANSY radar observations3.2.2 Numerical setup for NICAM3.2.2.1 Horizontal and vertical coordinate system3.2.2.2 Initial condition and other physical schemes3.3 Observational results3.4Numerical experiment results3.4.1 Simulated wave structures3.4.2 Wave propagation and generation mechanism3.5Discussion3.6Summary4. Gravity wave characteristics in the winter Antarctic mesosphere by a long-term numerical simulation using a non-hydrostatic general circulation model4.1 Data and method4.1.1 Horizontal and vertical coordinate system4.1.2 Initial condition and time integration technique4.2 Comparison to the PANSY radar data and the reanalysis data4.3 Spectrum analysis4.4 Flux, energy of gravity waves4.5 Discussion and Summary5. Summary and concluding remarksAcknowledgements