Global Distribution and Seasonal Variation of Transient Luminous Events Observed by ISUAL Over 12 Years.
Saved in:
| Title: | Global Distribution and Seasonal Variation of Transient Luminous Events Observed by ISUAL Over 12 Years. |
|---|---|
| Authors: | Lin, Y. C.1 (AUTHOR), Chen, A. B.1,2,3 (AUTHOR) alfred@ncku.edu.tw, Chuang, C. W.1 (AUTHOR), Su, H. T.1 (AUTHOR), Hsu, R. R.1 (AUTHOR) |
| Source: | Journal of Geophysical Research. Space Physics. Feb2026, Vol. 131 Issue 2, p1-16. 16p. |
| Subject Terms: | *Upper atmosphere, Atmospheric electricity, Spatial analysis (Statistics), Imaging systems |
| Abstract: | The Imager of Sprites and Upper Atmospheric Lightning (ISUAL) onboard the FORMOSAT‐2 satellite studied global Transient Luminous Events (TLEs), which occur between the troposphere and ionosphere. Using deep learning techniques, the ISUAL TLE event list from July 2004 to June 2016 was systematically constructed, containing 66,586 events. ISUAL is the satellite dedicated to TLE observation, mapping the global distribution of TLEs, and revealing distinct spatial patterns. Elves were most frequent over oceans, sprites over land, halos over coastal areas, and blue jets and gigantic jets predominantly in low‐latitude regions. This study first constructed a global TLE occurrence density map through the fusion of ISUAL TLE observations and World Wide Lightning Location Network intense lightning distributions. The corrected global TLE occurrence rate is 47.08 events per minute, notably exceeding earlier studies, with individual rates of elves (32.74), sprites (5.94), halos (2.98), blue jets (5.40), and gigantic jets (0.02). Furthermore, TLE occurrence rates were examined across different climate zones using the Köppen classification system. Higher rates were found in tropical and temperate climates, with sprites particularly frequent in hot summer regions. To further examine potential external drivers, this study for the first time analyzed a full 11‐year solar cycle activity in relation to nighttime TLE occurrence, revealing only a weak correlation (R ≤ 0.3) and favoring meteorological factors instead of solar activity as the primary drivers of TLE variability. Plain Language Summary: Transient Luminous Events (TLEs) are quick, colorful flashes that appear high above thunderstorms. Their family includes elves, sprites, halos, blue jets, and gigantic jets. A total of 66,586 TLEs are included in the ISUAL event list for July 2004 to June 2016. Elves were most common above oceans, sprites above land, halos along coastal areas, and gigantic jets near the equator. These patterns may reflect the type of storms: ocean storms with strong lightning often produce elves, while land storms with powerful updrafts produce more sprites. To give a complete global TLE distribution, a fusion of ISUAL results and worldwide energetic lightning data was used. This produced the first global map of TLEs, showing clusters in tropical and temperate regions. The corrected global occurrence rate is about 47 events per minute, which is much higher than previous estimates. For the first time, the connection between TLEs and the solar cycle was examined, but only a weak correlation (R ≤ 0.3) was found, indicating that TLEs are mainly shaped by weather in the lower atmosphere rather than by solar activity. Key Points: An algorithm was developed to systematically identify Transient Luminous Event (TLE) from 12‐year Imager of Sprites and Upper Atmospheric Lightning (ISUAL) observations to explore their spatiotemporal patternsThe corrected TLE occurrence rates by fusing the ISUAL observed density maps and World Wide Lightning Location Network energetic lightning distribution are derivedThe statistical correlations of TLEs with the solar cycle as well as climate classification are revealed for the first time [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Space Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | GreenFILE |
| Abstract: | The Imager of Sprites and Upper Atmospheric Lightning (ISUAL) onboard the FORMOSAT‐2 satellite studied global Transient Luminous Events (TLEs), which occur between the troposphere and ionosphere. Using deep learning techniques, the ISUAL TLE event list from July 2004 to June 2016 was systematically constructed, containing 66,586 events. ISUAL is the satellite dedicated to TLE observation, mapping the global distribution of TLEs, and revealing distinct spatial patterns. Elves were most frequent over oceans, sprites over land, halos over coastal areas, and blue jets and gigantic jets predominantly in low‐latitude regions. This study first constructed a global TLE occurrence density map through the fusion of ISUAL TLE observations and World Wide Lightning Location Network intense lightning distributions. The corrected global TLE occurrence rate is 47.08 events per minute, notably exceeding earlier studies, with individual rates of elves (32.74), sprites (5.94), halos (2.98), blue jets (5.40), and gigantic jets (0.02). Furthermore, TLE occurrence rates were examined across different climate zones using the Köppen classification system. Higher rates were found in tropical and temperate climates, with sprites particularly frequent in hot summer regions. To further examine potential external drivers, this study for the first time analyzed a full 11‐year solar cycle activity in relation to nighttime TLE occurrence, revealing only a weak correlation (R ≤ 0.3) and favoring meteorological factors instead of solar activity as the primary drivers of TLE variability. Plain Language Summary: Transient Luminous Events (TLEs) are quick, colorful flashes that appear high above thunderstorms. Their family includes elves, sprites, halos, blue jets, and gigantic jets. A total of 66,586 TLEs are included in the ISUAL event list for July 2004 to June 2016. Elves were most common above oceans, sprites above land, halos along coastal areas, and gigantic jets near the equator. These patterns may reflect the type of storms: ocean storms with strong lightning often produce elves, while land storms with powerful updrafts produce more sprites. To give a complete global TLE distribution, a fusion of ISUAL results and worldwide energetic lightning data was used. This produced the first global map of TLEs, showing clusters in tropical and temperate regions. The corrected global occurrence rate is about 47 events per minute, which is much higher than previous estimates. For the first time, the connection between TLEs and the solar cycle was examined, but only a weak correlation (R ≤ 0.3) was found, indicating that TLEs are mainly shaped by weather in the lower atmosphere rather than by solar activity. Key Points: An algorithm was developed to systematically identify Transient Luminous Event (TLE) from 12‐year Imager of Sprites and Upper Atmospheric Lightning (ISUAL) observations to explore their spatiotemporal patternsThe corrected TLE occurrence rates by fusing the ISUAL observed density maps and World Wide Lightning Location Network energetic lightning distribution are derivedThe statistical correlations of TLEs with the solar cycle as well as climate classification are revealed for the first time [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 21699380 |
| DOI: | 10.1029/2025JA034726 |
