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| Autor: | Hsiu-Shan Yu, 余秀珊 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 Solar latitudinal differential rotation, which can generate toroidal magnetic field from a poloidal magnetic field, plays an important role on solar dynamo and formation of solar cycle. Solar differential rotation was first found by tracing sunspots' motion. The well-known solar differential rotation formula obtained from sunspots' motion is only applicable to the middle- and lower- latitude regions and has a poor latitudinal resolution during solar minimum. Supergranulations, or chromosphere networks, or plages are excellent targets for studying solar differential rotation in all latitudes and during different phases of solar cycle. The one-minute broadband K-line images obtained from Taiwan Oscillation Network (TON) provide an opportunity to study differential rotation of supergranulations or plages up to very high latitude. Our preliminary results show that weak north-south asymmetry on solar differential rotation is found during years 1994~1997. Strong north-south asymmetry on solar differential rotation is found during years 1998~2000. According to our preliminary study, solar rotation rate decreases with time in northern hemisphere, but increases with time in southern hemisphere during years 1994~2000. However, further study indicates that the strong north-south asymmetry on solar differential rotation may partially due to incorrect mapping of the TON data sets we used in this thesis. Thus, our study of solar cycle dependence on solar differential rotation is not fully successful. But, in this thesis we have developed a very efficient way to obtain solar rotation rate at different latitude. We have also found a simple way to check and to improve the accuracy of a remapped image. Therefore, using the techniques developed in this thesis can provide accurate remapped images and real-time solar differential rotation information for future solar seismology study using TON data sets. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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