Presentation Information
[O12-P34]Statistical analysis of transient luminous event sprites
*Minamo Ishimura1, *Shodai Matsuda1, Riku Nakamura1 (1. Kochi Prefectural Kochi Ozu High School)
Keywords:
Sprites,transient luminous event,statistical analysis
1. Background and Purpose
Transient luminous events (TLEs) occur at altitudes of 50–100 km in association with lightning. Sprites, a type of TLE, mainly occur at 50–90 km and are often generated by positive cloud-to-ground lightning. In Japan, they are frequently observed over the Wakasa Bay area in winter.Our observation network, established in 2006, has recorded 6,512 TLEs by 2022, including over 560 simultaneous observations. However, many aspects of sprite occurrence remain unclear. Therefore, this study aims to clarify relationships among occurrence location, number, and morphology mainly in the Sea of Japan coastal region, including the Wakasa Bay area, using statistical analysis of simultaneous events.
2. Methods
2-1. Observation Method
We used CCD cameras (Watec WAT-100N) and recording software to capture events. From about 500 simultaneous observations, 73 events (162 images) were selected for analysis.
2-2. Analysis Method
Sprite coordinates were first estimated using UFO Analyzer V2, assuming top and bottom altitudes of 80 km and 70 km. Then, Sprite Analyzer was used to determine occurrence locations based on multi-point observations.
3. Results
3-1. Observation Status by School
A total of 6,616 events were observed, with the highest annual count being 391. By school, Sanbonmatsu High School recorded 31% of events, followed by Iwata Minami High School (28%).
3-2. Accuracy Comparison Between Two-Point and Three-Point Observations
Comparison of two- and three-point observations showed differences of about ±0.15° in latitude/longitude, ±6 km (top), and ±4.5 km (bottom).
3-3. Data Analysis Results
No clear relationship was found between sprite shape and region, nor between single and multiple occurrences. However, sprites were distributed over horizontal distances of about 10–70 km, with many events concentrated at 30–40 km.
4. Discussion and Future Work
No clear spatial tendency was identified in this dataset. However, the concentration at 30–40 km suggests a possible underlying factor, which requires further investigation.
Future work will include analysis incorporating morphology and increasing the dataset size for more accurate results.
Transient luminous events (TLEs) occur at altitudes of 50–100 km in association with lightning. Sprites, a type of TLE, mainly occur at 50–90 km and are often generated by positive cloud-to-ground lightning. In Japan, they are frequently observed over the Wakasa Bay area in winter.Our observation network, established in 2006, has recorded 6,512 TLEs by 2022, including over 560 simultaneous observations. However, many aspects of sprite occurrence remain unclear. Therefore, this study aims to clarify relationships among occurrence location, number, and morphology mainly in the Sea of Japan coastal region, including the Wakasa Bay area, using statistical analysis of simultaneous events.
2. Methods
2-1. Observation Method
We used CCD cameras (Watec WAT-100N) and recording software to capture events. From about 500 simultaneous observations, 73 events (162 images) were selected for analysis.
2-2. Analysis Method
Sprite coordinates were first estimated using UFO Analyzer V2, assuming top and bottom altitudes of 80 km and 70 km. Then, Sprite Analyzer was used to determine occurrence locations based on multi-point observations.
3. Results
3-1. Observation Status by School
A total of 6,616 events were observed, with the highest annual count being 391. By school, Sanbonmatsu High School recorded 31% of events, followed by Iwata Minami High School (28%).
3-2. Accuracy Comparison Between Two-Point and Three-Point Observations
Comparison of two- and three-point observations showed differences of about ±0.15° in latitude/longitude, ±6 km (top), and ±4.5 km (bottom).
3-3. Data Analysis Results
No clear relationship was found between sprite shape and region, nor between single and multiple occurrences. However, sprites were distributed over horizontal distances of about 10–70 km, with many events concentrated at 30–40 km.
4. Discussion and Future Work
No clear spatial tendency was identified in this dataset. However, the concentration at 30–40 km suggests a possible underlying factor, which requires further investigation.
Future work will include analysis incorporating morphology and increasing the dataset size for more accurate results.