dc.contributor.author |
Hughes, S. J |
|
dc.contributor.author |
Rajaguru, S. P |
|
dc.contributor.author |
Thompson, M. J |
|
dc.date.accessioned |
2009-07-15T15:56:21Z |
|
dc.date.available |
2009-07-15T15:56:21Z |
|
dc.date.issued |
2004-10 |
|
dc.identifier.citation |
D. Danesy., ed., Proceedings of the SOHO 14 / GONG 2004 Workshop (ESA SP-559). "Helio- and Asteroseismology: Towards a Golden Future". 12 - 16 July, 2004. pp. 493 - 496 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/4640 |
|
dc.description.abstract |
Travel times of acoustic waves are calculated from Dopplergrams of solar oscillations obtained using the Global Oscillation Network Group (GONG) ground-based network and the Michelson Doppler Imager (MDI) instrument on board the SOHO satellite. These travel times are invested using a standard ray approximation to ascertain the sound-speed anomalies below two active regions. Some simple methods for ignoring the possibly corrupted measurements from within a sunspot are considered, as are diagnostics fro optimizing the inversion. Results are then presented for two different spot regions and the results of the instruments are compared: both regions behave in similar ways and the agreements between the two instruments is good. First-skip and second-skip data are found to produce similar results for deeper layers of the model, but the significance of the shallower results from second-skip data is questionable. We conclude that the use of GONG data fro time-distance analysis is appropriate. |
en |
dc.language.iso |
en |
en |
dc.publisher |
European Space Agency |
en |
dc.relation.ispartofseries |
ESA SP; No. 559 |
|
dc.relation.uri |
http://adsabs.harvard.edu/abs/2004ESASP.559..493H |
en |
dc.rights |
© European Space Agency |
en |
dc.subject |
Sun: Activity |
en |
dc.subject |
Sun: Oscillations |
en |
dc.subject |
Sunspots |
en |
dc.title |
Comparison of GONG and MDI sound-speed anomalies beneath two active regions |
en |
dc.type |
Article |
en |