1:45 PM - 3:15 PM
[O08-P10] Comparison of summer and winter sprite columns focusing on luminous altitude and morphology
Keywords:sprite, morphology, summer
§1. Motivation and purpose
Our research has focused on high-altitude luminescence phenomena. In a previous study, it was confirmed that the area of winter sprite columns is proportional to the number and length of sprite columns, respectively. Peak current intensity (kA) is proportional to the electromagnetic pulse, and since the area of a sprite is proportional to the electromagnetic pulse, it was confirmed that Peak current intensity (kA) is proportional to the area.
§2.What are sprites?
A sprite is a type of high-altitude luminous phenomenon that is generated by the inter-ground discharge of thunderclouds, with the lower end at an altitude of about 70 km and the upper end at about 80 km. Sprites are known to have various shapes, and in this study, we classified them into four types: (1) Column (columnar), (2) Angel (with angel wing-like parts), (3) Carrot (with carrot-like parts), and (4) Wishbone Tree (with branching parts) (Bor, 2013). Sprite columns are hereafter referred to as columns.
§3.Research Method
The images captured by each of the three high-sensitivity CCD cameras are constantly monitored by motion detection software to perform automatic observation. The PC also identifies the location of the sprite based on the camera's field of view. Furthermore, the sprites are classified by shape, and the area of each sprite is calculated using area measurement software (lenaraf220b), and the correlation between the number of sprites, length, and altitude is investigated. For this reason, events in which multiple types of sprites occurred at the same time were excluded.
§4.Results
4-1. Area by Shape (Column)
A positive correlation was found between the number of sprites and area. A positive correlation was also observed between the length and area. Furthermore, a positive correlation was found between the altitude and the area.
4-2. Area by Shape (Carrot)
The relationship between the number of sprites and area was examined, and a positive correlation was found. A weak positive correlation was also observed between the length and area. Furthermore, the relationship between altitude and area was examined, and a very weak positive correlation was found.
§5.Consideration
In the previous study, it was confirmed that the number of pillars, length, altitude, and area were almost proportional to each other in the winter column. The same relationship was observed for summer columns, suggesting that there is no significant difference in the occurrence of columns in summer and winter.
The fact that the area and the number of trees in the summer carrot were proportional suggests that the area per tree is constant. On the other hand, the relationship between area and length was weakly positively correlated, suggesting that the width of the column is not constant in Summer Carrot. In addition, the area per column in Summer Carrot is considered to be more constant than that in Summer Column, but the length, thickness, and elevation of the columns are considered to be more varied.
The weak correlation between area, length, and height in the summer Carrot may be due to the small number of Carrots analyzed.
§6.Conclusion
The same relationship as that of WinterColumn was found in SummerColumn, indicating that there is no significant difference in the mode of occurrence between them. In addition, the occurrence pattern of Summer Column is always the same as that of Summer Carrot, while that of Summer Carrot is not always the same.
§7. Future Prospects
We would like to investigate what kind of relationship exists in sprites other than columnar sprites and make a comparison with columnar sprites.
We would like to increase the number of sprites analyzed and make more accurate measurements.
We would like to investigate whether the environment at the time the sprites were generated may have affected the analysis results.
§8.References
József Bór, 2013, Optically perceptible characteristics of sprites observed in Central Europe in 2007-2009
Adachi, T., et al. (2004), Geophys. Res. Lett. doi:10.1029/2003GL019081.
Utsunomiya, O., and T. Kamikawa, 2022, Relationship between winter sprite shape and meteorological conditions.
§9. Acknowledgments
I would like to thank again Akira Aoshima, visiting researcher at the Fujinokuni Museum of Environmental History, Hiroyuki Kurematsu, advisor, and members of the Geoscience Department for their cooperation in my research.
Our research has focused on high-altitude luminescence phenomena. In a previous study, it was confirmed that the area of winter sprite columns is proportional to the number and length of sprite columns, respectively. Peak current intensity (kA) is proportional to the electromagnetic pulse, and since the area of a sprite is proportional to the electromagnetic pulse, it was confirmed that Peak current intensity (kA) is proportional to the area.
§2.What are sprites?
A sprite is a type of high-altitude luminous phenomenon that is generated by the inter-ground discharge of thunderclouds, with the lower end at an altitude of about 70 km and the upper end at about 80 km. Sprites are known to have various shapes, and in this study, we classified them into four types: (1) Column (columnar), (2) Angel (with angel wing-like parts), (3) Carrot (with carrot-like parts), and (4) Wishbone Tree (with branching parts) (Bor, 2013). Sprite columns are hereafter referred to as columns.
§3.Research Method
The images captured by each of the three high-sensitivity CCD cameras are constantly monitored by motion detection software to perform automatic observation. The PC also identifies the location of the sprite based on the camera's field of view. Furthermore, the sprites are classified by shape, and the area of each sprite is calculated using area measurement software (lenaraf220b), and the correlation between the number of sprites, length, and altitude is investigated. For this reason, events in which multiple types of sprites occurred at the same time were excluded.
§4.Results
4-1. Area by Shape (Column)
A positive correlation was found between the number of sprites and area. A positive correlation was also observed between the length and area. Furthermore, a positive correlation was found between the altitude and the area.
4-2. Area by Shape (Carrot)
The relationship between the number of sprites and area was examined, and a positive correlation was found. A weak positive correlation was also observed between the length and area. Furthermore, the relationship between altitude and area was examined, and a very weak positive correlation was found.
§5.Consideration
In the previous study, it was confirmed that the number of pillars, length, altitude, and area were almost proportional to each other in the winter column. The same relationship was observed for summer columns, suggesting that there is no significant difference in the occurrence of columns in summer and winter.
The fact that the area and the number of trees in the summer carrot were proportional suggests that the area per tree is constant. On the other hand, the relationship between area and length was weakly positively correlated, suggesting that the width of the column is not constant in Summer Carrot. In addition, the area per column in Summer Carrot is considered to be more constant than that in Summer Column, but the length, thickness, and elevation of the columns are considered to be more varied.
The weak correlation between area, length, and height in the summer Carrot may be due to the small number of Carrots analyzed.
§6.Conclusion
The same relationship as that of WinterColumn was found in SummerColumn, indicating that there is no significant difference in the mode of occurrence between them. In addition, the occurrence pattern of Summer Column is always the same as that of Summer Carrot, while that of Summer Carrot is not always the same.
§7. Future Prospects
We would like to investigate what kind of relationship exists in sprites other than columnar sprites and make a comparison with columnar sprites.
We would like to increase the number of sprites analyzed and make more accurate measurements.
We would like to investigate whether the environment at the time the sprites were generated may have affected the analysis results.
§8.References
József Bór, 2013, Optically perceptible characteristics of sprites observed in Central Europe in 2007-2009
Adachi, T., et al. (2004), Geophys. Res. Lett. doi:10.1029/2003GL019081.
Utsunomiya, O., and T. Kamikawa, 2022, Relationship between winter sprite shape and meteorological conditions.
§9. Acknowledgments
I would like to thank again Akira Aoshima, visiting researcher at the Fujinokuni Museum of Environmental History, Hiroyuki Kurematsu, advisor, and members of the Geoscience Department for their cooperation in my research.