Date of Award
8-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Aerospace, Physics, and Space Sciences
First Advisor
Hamid K. Rassoul
Second Advisor
Amitabh Nag
Third Advisor
Kenneth Cummins
Fourth Advisor
Brian Lail
Abstract
The extremes of lightning, specifically lightning with long-lasting continuing currents and lightning with extremely high peak currents, are investigated from both ground- and space-based observations. Additionally, the potential solar influence on lightning is investigated on large spatial scales.
Continuing currents may occur following the impulsive flow of current during a cloud-to-ground (CG) return stroke and are usually low amplitude (from a few amperes to a few kiloamperes) and long duration (several to hundreds of milliseconds). Remotely estimating their duration from the electromagnetic fields measured by existing ground-based lightning locating systems (LLSs) is not possible, but some space-based lightning detection systems may be able to. The capabilities of a space-based optical lightning detection system, called the Geostationary Lightning Mapper (GLM), to detect and measure the durations of continuing currents in flashes in Florida are examined.
The typical peak current of negative CG lightning is approximately 30 kiloamps. However, some peak currents in CG lightning can reach hundreds of kiloamps. Recently, the development of LLSs has provided the opportunity to understand lightning with large estimated peak currents. The characteristics of this extreme lightning are examined using data from the Global Lightning Dataset (GLD360) and from the U.S. National Lightning Detection Network (NLDN).
Understanding influences over lightning provides insight for lightning modeling. Using lightning data provided by the GLD360 and NLDN, the solar influence over lightning is investigated, specifically when stream interaction regions (SIRs), Forbush Decreases (FDs) or sharp decreases in galactic cosmic ray (GCR) flux, and geomagnetic storms occur.
Recommended Citation
Mark, Megan Diane, "Investigating Global Lightning Observed from Ground and Space, and its Relationship to Solar Activity" (2025). Theses and Dissertations. 1595.
https://repository.fit.edu/etd/1595