AEM “Thunder Hours” Paper Formally Published by Bulletin of the American Meteorological Society (BAMS)

In 2021, AEM’s Research and Development team submitted a paper to the Bulletin of the American Meteorological Society (BAMS) titled, “Thunder Hours: How Old Methods Offer New Insights into Thunderstorm Climatology”. This year, the paper was officially published by Bulletin of the American Meteorological Society (BAMS). BAMS is an incredibly high-profile, peer-reviewed journal which is designed for a broader audience than most journals— although papers published by BAMS are scientifically rigorous, they are written not only for scientists, but also for forecasters, emergency managers, private sector representatives, broadcasters, and more. It is an esteemed honor that AEM’s “Thunder Hours” paper has been published in such a high-impact and widely-read journal.

A Look into the Datasets and Thunder Hours

Thunder Hours: How Old Methods Offer New Insights into Thunderstorm Climatology” features EN and WWLLN data in the form of a 5-year global thunder hour climatology. A thunder hour is an hour during which thunder could be heard from a location, which roughly equates the dataset to a global thunderstorm climatology— the scientific logic behind “thunder hours” is explained in more detail in the paper. The dataset is used to discuss patterns in global thunderstorm distribution through a few different lenses, and demonstrates the utility of generating thunder hours from total lightning data for climate research. The paper also features a “thunder anomalies” analysis of some regions, and highlights potential future climate research applications for the dataset and method.

AEM’s Research & Development team created a website for the dataset, which also further explores what you can do with thunder hours and the value of working with thunder instead of flashes.

Abstract: “Thunder Hours: How Old Methods Offer New Insights into Thunderstorm Climatology” 

Lightning data are often used to measure the location and intensity of thunderstorms. This study presents 5 years of data from the Earth Networks Global Lightning Detection Network (ENGLN) in the form of thunder hours. A thunder hour is defined as an hour during which thunder can be heard from a given location, and thunder hours can be calculated for the entire globe. Thunder hours are an intuitive measure of thunderstorm frequency where the 1-h interval corresponds to the life-span of most thunderstorms, and the hourly temporal resolution of the data also represents long-lived systems well. Flash-density-observing systems are incredibly useful, but they have some drawbacks that limit how they can be used to quantify global thunderstorm activity on a climatological scale: flash density distributions derived from satellite observations must sacrifice a great deal of their spatial resolution in order to capture the diurnal convective cycle, and the detection efficiencies of ground-based lightning detection systems are not uniform in space or constant in time. Examining convective patterns in the context of thunder hours lends insight into thunderstorm activity without being heavily influenced by network performance, making thunder hours particularly useful for studying thunderstorm climatology. The ENGLN thunder hour dataset offers powerful utility to climatological studies involving lightning and thunderstorms. This study first shows that the ENGLN thunder hours dataset is very consistent with past measurements of global thunderstorm activity and the global electric circuit using only 5 years of data. Then, this study showcases thunder anomaly fields, designed to be analogous to temperature anomalies, which can be used to diagnose changes in thunderstorm frequency relative to the long-term mean in both time and space.

To read the full paper, check out the “Thunder Hours: How Old Methods Offer New Insights into Thunderstorm Climatologypublication by the Bulletin of the American Meteorological Society (BAMS).

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