Ionospheric Responses to Acoustic and Gravity Waves Generated from Derechos

Lower atmospheric convective events such as thunderstorms, tornadoes, and hurricanes are an important mechanisms that generate acoustic and gravity waves (AGWs) which can propagate to the upper atmosphere and generate disturbances in the ionosphere. A derecho is a special type of damaging and long-lived thunderstorm that can form under specific wind conditions within mesoscale convective systems (MCS). They are different from tornadoes or hurricanes as their associated strong winds flow in straight lines, causing damage that is often termed straight-line wind damage. In this study, we investigate AGW signals during derecho events over the continental US in a multi-layer manner. We analyze data from different satellite- and ground-based measurements to investigate AGW-related fluctuations over a range of atmospheric layers and the resulting ionospheric responses. The data analyzed includes Total Electron Content (TEC) perturbations from Global Navigation Satellite System (GNSS) measurements, stratospheric brightness temperatures from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA’s Aqua satellite, and precipitation rate measurements from the Next Generation Weather Radar (NEXRAD) network. We analyze spatial and temporal characteristics of the AGWs and Traveling Ionospheric Disturbances (TIDs) generated over derechos, and their correlation with properties of the associated MCS such as wind speeds and precipitation rates. Furthermore, using the Model for Acoustic and Gravity wave Interactions and Coupling (MAGIC) and the Geospace Environment Model for Ion-Neutral Interactions (GEMINI), observations from one derecho event are compared with thermospheric and ionospheric simulations from the coupled MAGIC-GEMINI model. The objective of the study is to ultimately determine if the TID characteristics differ between derecho events, and if the TID characteristics from derechos differ from those resulting from other convective systems. Such a comparison is of scientific significance as it can highlight missing considerations of the physics of how different convective sources couple the lower atmosphere to the ionosphere.