Dynamical Characteristics of Inertia-Gravity Waves in the Antarctic Mesosphere: Analyses Combining High-Resolution Observations and Modeling

ISBN-13: 9789811390876 / Angielski / Miękka / 2021 / 92 str.

Ryosuke Shibuya

Spis treści

Abstract

Contents

List of Figure captions

List of Table captions

1. General Introduction

1.1 Dynamical properties of gravity waves

1.2 Gravity waves in the Antarctic

1.3 Observational and modeling studies of the mesospheric gravity waves in the Antarctic

1.4 The Purpose of this study

2. A new transformation method for a quasi-uniform and fine grid system in a circular region using the spring dynamics

2.1 A short review for the previous stretched grid systems

2.2 A standard grid generation method in NICAM

2.2.1 Icosahedral grid on a sphere

2.2.2 Spring dynamics

2.3 How to determine the characteristic spring length

2.3.1 A constraint on the cell area and total grid number over the sphere

2.3.2 Connection with the Schmidt transformation

2.3.3 The mathematical constraints on ϕ0, n, and β

2.4. Results: Grid properties

2.4.1 Resolution

2.4.2 Smoothness and Isotropy

2.4.3 Numerical simulation

2.5 Summary and concluding remarks

3. 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 disturbances

3.2 Methodology

3.2.1 The PANSY radar observations

3.2.2 Numerical setup for NICAM

3.2.2.1 Horizontal and vertical coordinate system

3.2.2.2 Initial condition and other physical schemes

3.3 Observational results

3.4 Numerical experiment results

3.4.1 Simulated wave structures

3.4.2 Wave propagation and generation mechanism

3.5 Discussion

3.6 Summary

4. Gravity wave characteristics in the winter Antarctic mesosphere by a long-term numerical simulation using a non-hydrostatic general circulation model

4.1 Data and method

4.1.1 Horizontal and vertical coordinate system

4.1.2 Initial condition and time integration technique

4.2 Comparison to the PANSY radar data and the reanalysis data

4.3 Spectrum analysis

4.4 Flux, energy of gravity waves

4.5 Discussion and Summary

5. Summary and concluding remarks

Acknowledgements

O autorze

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.

Blurb

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