Ionospheric Responses to Acoustic and Gravity Waves Generated from Derechos

A derecho is a special type of damaging and long-lived thunderstorm that can form when certain wind conditions are present within a complex of thunderstorms termed mesoscale convective systems (MCS). A derecho event typically occurs a few times a year in the United States (US), most commonly during summer in the Mid- and Southwest. They are different from tornados or hurricanes because the associated high wind speeds of a derecho system move forward in straight lines, causing damage that is often termed straight-line wind damage. In this study, we investigate acoustic and gravity wave (AGW) signals during a set of derecho events over the continental US in a multi-layer manner. We analyze data from different satellite and ground-based measurements to investigate AGW evolution over a wide range of atmospheric layers and the resulting ionospheric responses. The data analyzed includes the ionosphere total electron content (TEC) perturbations from GNSS measurements, stratospheric brightness temperatures from the Atmospheric Infrared Sounder (AIRS), and precipitation rate and reflectivity measurements from the Next Generation Weather Radar (NEXRAD) to constrain the atmospheric movement associated with the studied derecho events. 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. A comparison of AGW and TID characteristics is made between derecho events and those resulting from ordinary thunderstorms. Our study highlights the complexity of analyzing coupled lower atmosphere-ionosphere processes and illustrates the type of ionospheric responses that can be expected from a derecho event.