Meridional Motion and Reynolds Stress from Debrecen Photoheliographic Data

0480935 - ASÚ 2018 RIV NL eng J - Článek v odborném periodiku
Sudar, D. - Brajša, R. - Skokić, Ivica - Beljan, I.P. - Woehl, H.
Meridional Motion and Reynolds Stress from Debrecen Photoheliographic Data.
Solar Physics. Roč. 292, č. 7 (2017), 86/1-86/13. ISSN 0038-0938. E-ISSN 1573-093X
Grant CEP: GA MŠMT(CZ) 7E13003
GRANT EU: European Commission(XE) 312495 - SOLARNET
Institucionální podpora: RVO:67985815
Klíčová slova: sunspots * rotation * velocity fields
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 2.580, rok: 2017

he Debrecen Photoheliographic Data catalogue is a continuation of the Greenwich Photoheliographic Results providing daily positions of sunspots and sunspot groups. We analyse the data for sunspot groups focussing on meridional motions and transfer of angular momentum towards the solar equator. Velocities are calculated with a daily shift method including an automatic iterative process of removing the outliers. Apart from the standard differential rotation profile, we find meridional motion directed towards the zone of solar activity. The difference in measured meridional flow in comparison to Doppler measurements and some other tracer measurements is interpreted as a consequence of different flow patterns inside and outside of active regions. We also find a statistically significant dependence of meridional motion on rotation velocity residuals confirming the transfer of angular momentum towards the equator. Analysis of horizontal Reynolds stress reveals that the transfer of angular momentum is stronger with increasing latitude up to about 40 degrees, where there is a possible maximum in absolute value.
Trvalý link: http://hdl.handle.net/11104/0276595