Search Constraints
1 - 3 of 3
Number of results to display per page
View results as:
Search Results
1. A Statistical Analysis of High-frequency Transient-Large-Amplitude Geomagnetic Disturbances: Data
- Creator:
- McCuen, Brett A.
- Description:
- We present a comprehensive statistical analysis of high-frequency transient-large-amplitude (TLA) magnetic perturbation events that occurred at 12 high-latitude ground magnetometer stations throughout solar cycle 24 from 2009 to 2019. TLA signatures are defined as one or more second-timescale dB/dt interval with magnitude ≥ 6 nT/s within an hour event window. This study characterizes high-frequency TLA events based on their spatial and temporal behavior as well as relation to auroral substorms, geomagnetic storm phases and nighttime geomagnetic disturbance events events (GMD). We show that TLA events occur primarily at nighttime and solely in the high-latitude region above 60 degrees geomagnetic latitude. The largest TLA events occurred more often in the declining phase of the solar cycle when solar wind velocity was higher and ring current activity was lower, suggesting association to high-speed flows caused by coronal holes and subsequent corotating interaction regions reaching Earth. TLA perturbations often occurred preceding or within the most extreme nighttime geomagnetic disturbance (GMD) events with 5-10 minute timescales, but the TLA intervals were often even more localized than the ~300 km effective radius of GMDs: occurring at only some of the stations at which GMDs occurred. We show that TLA-related GMD events can result from dipolarization fronts in the magnetotail and fast flows toward Earth and are closely temporally associated to poleward boundary intensifications (PBI) and auroral streamers. The highly localized behavior and connection to the most extreme GMD events suggests that TLA intervals are a ground manifestation of the features within rapid and complex ionospheric structures that can drive GICs.
- Keyword:
- geomagnetic field, high frequency, space weather, transient-large-amplitude, TLA, high frequency dB/dt, dB/dt search algorithm
- Citation to related publication:
- McCuen, B. A., Moldwin, M. B., Engebretson, M. J., Weygand, J. G., Nishimura, Y. (2023). A Statistical Analysis of High-frequency Transient-Large-Amplitude Geomagnetic Disturbance. [To be submitted to] Journal of Geophysical Research: Space Physics
- Discipline:
- Science
- Creator:
- McCuen, Brett A.
- Description:
- The data were used to study the high-frequency geomagnetic disturbances within the magnetic field data. Included in this repository are the python scripts that perform an identification and classification of high-frequency signals within the magnetometer data that is downloaded from the databases listed in the Methodology section. All analysis and plots were created using subsequent Python libraries. The machine learning study implemented libraries from the sci-kit learn software. All of the specific methodology can be accessed in the readme.txt script.
- Keyword:
- geomagnetic field, high frequency, space weather, transient-large-amplitude, TLA, high frequency dB/dt, and dB/dt search algorithm
- Discipline:
- Science
- Creator:
- McCuen, Brett A.
- Description:
- These data are TLA events identified in MACCS magnetometer data throughout 2015. These events are short-timescale (< 60 s), large -amplitude (> 6 nT/s) magnetic disturbances measured at Earth's surface that are analyzed for space weather research purposes. and The events were identified in a year's worth of magnetic field data using an algorithm developed in the MATLAB platform. The algorithm dBdt_main.m can be run using the associated scripts (clean_maccs.m, simple_dbdt.m, extremes1.m, newdbdt.m) to return the events in the 2015_AllEvents.csv file. The substorm onset delays of each event are determined with the onset_delays.m script and the substorm event list 20191127-15-56-substorms.csv (both included).
- Keyword:
- space weather impacts, geomagnetically induced currents, GIC, transient induced currents, transient large amplitude, dB/dt search algorithm, and TLA
- Citation to related publication:
- Engebretson, M. J., Pilipenko, V. A., Ahmed, L. Y., Posch, J. L., Steinmetz, E. S., Moldwin, M. B., … Vorobev, A. V. (2019). Nighttime Magnetic Perturbation Events Observed in Arctic Canada: 1. Survey and Statistical Analysis. Journal of Geophysical Research: Space Physics, 124(9), 7442–7458. https://doi.org/10.1029/2019JA026794
- Discipline:
- Science