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2023 Workshop: Traveling Ionospheric Disturbances

Long title
Traveling Ionospheric Disturbances Driven from Above and from Below
Grand Challenge
Conveners
Kate Zawdie
Jeff Klenzing
Meghan Burleigh
Shunrong Zhang
Pavel Inchin
Steve Kaeppler
Danielle Markowski
Lakshmi Narayanan
Matt Zettergren
kate.zawdie@nrl.navy.mil
Description

This session will focus on the identification and source differentiation of traveling ionospheric disturbances (TIDs), which are frequently observed in the ionosphere at all latitudes and longitudes. TIDs can be driven from above by solar and magnetospheric disturbances, or driven from below by lower atmospheric and surface forcing, including but not limited to tropospheric weather events (hurricanes, tornadoes, tropical cyclones, thunderstorms, etc.), earthquakes, tsunamis, volcanic eruptions, explosions, and spacecraft launches. TIDs generated from different types of sources may exhibit similar or very different characteristics in their spatial and temporal scales, periodicities, propagation speeds and directions. Meanwhile, TIDs generated from the same type of sources may exhibit different characteristics depending on the local atmospheric and ionospheric conditions. Therefore, it remains a challenge to distinguish TIDs from different types of sources in ionospheric observations. We solicit theoretical, observational, and modeling contributions on better understanding of the origins, generation mechanisms, and characteristics of TIDs. In particular, we welcome innovative approaches to identify and differentiate TIDs generated from various sources.

Justification

Traveling Ionospheric Disturbances (TIDs) are a ubiquitous feature that are observed as propagating density perturbations in the F-region ionosphere. They have been detected by many different instruments over many decades. Various physical processes are believed to be responsible for the generation of these wave-like features. TIDs can be driven from above by solar and magnetospheric disturbances, or driven from below by lower atmospheric and surface forcing, including but not limited to tropospheric weather events (hurricanes, tornadoes, tropical cyclones, thunderstorms, etc.), earthquakes, tsunamis, volcanic eruptions, explosions, and spacecraft launches. TIDs generated from different types of sources may exhibit similar or very different characteristics in their spatial and temporal scales, periods, propagation speeds and directions. Meanwhile, TIDs generated from the same type of sources may exhibit different characteristics depending on the local atmospheric and ionospheric conditions. Therefore, it remains a challenge to distinguish TIDs from different types of sources in ionospheric observations.

A key obstacle in developing future space weather forecast systems is to predict the physical mechanisms (and their scales) that drive regional ionospheric perturbations, such as TIDs. There have been recent efforts to mitigate the effects of TIDs on HF geolocation, but in order to predict TID occurrence, their generation mechanisms must be understood. The sparse nature of measurements in the ionosphere makes it unlikely that these questions can be answered via observational methods alone. Comprehensive modeling studies combined with new, multi-instrument observations will be required to obtain closure on these science questions.

Proposed Timeline of Yearly Focus Topics (for Grand Challenge Workshop)

Year 1: Presentations from select speakers to outline technical and knowledge gaps. Hold a discussion to select a time period to undertake collaborative data/model studies in the next year.
Year 2: Present results from first collaborative study. Re-examine gaps and select a new time period for collaborative studies in the next year.
Year 3: Present results from second collaborative study. Discuss progress on goals and document open questions.

Suggested Tutorial Speakers (for Grand Challenge Workshop)

Joe Huba/Tatsu Yokoyama/Yuichi Otsuka: Modeling Electrified TIDs
Hanli Liu/Sharon Vadas/Pavel Inchin: Modeling atmospheric gravity waves
Shunrong Zhang/Carlos Martinis: Ground based observations of TIDs
Jeff Klenzing/Katelynn Greer: Space based observations of TIDs

Related to CEDAR Science Thrusts:
Explore exchange processes at boundaries and transitions in geospace
Develop observational and instrumentation strategies for geospace system studies
Keywords
Traveling Ionosphere Disturbance, Magnetosphere-Ionosphere-Atmosphere Interactions