A study of gravity waves on planetary atmospheres

• Main Author: Srivastava, Sarthak
• Other Authors: Lee Yee Hui
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Science::Physics; Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/170351
• Institution: Nanyang Technological University

Gravity waves (GWs) are internal atmospheric waves that exist on all planetary atmospheres and play an important role in atmospheric coupling, composition, variability, and structure. GWs transport energy and momentum from the lower to the upper atmosphere. GWs can influence upper atmospheric winds, composition, contribute to turbulence and can play vital roles in influencing the mean circulation and thermal structure of the atmosphere. Despite the key influencing role of GW activity on planetary atmospheres, there is lack of a general numerical model for comparative numerical experimentation. Several numerical models for GW simulation on specific planets exist in the literature. Moreover, most of these models are either, too simplistic and make drastically simplifying assumptions, or they are detailed and require significant computational resources. This study aims to obtain a general understanding of the influence of GW activity on terrestrial planetary atmospheres via creation of a numerical model that is computationally lightweight yet captures the essential nonlinear GW dynamics. Intra-atmospheric coupling due to GWs is demonstrated by studying the GPS total electron content perturbations induced by waves triggered by the 2004 Sumatra Earthquakes. A two-dimensional nonlinear numerical model is then developed to study atmospheric coupling due to Acoustic Gravity Waves (AGWs) on different planets. The model is validated and applied to real case studies of tsunamigenic GWs on Earth and CO2 ice cloud formation on Mars. The model is further applied to evaluate the detectability of GWs from a spacecraft instrument. Finally, a parametric study is conducted to understand the influence of wave frequency on GW propagation across Earth, Venus, and Mars.