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Cyclic Variation in the Solar Lower Atmosphere

Published online by Cambridge University Press:  13 May 2016

C. Fang
Affiliation:
Department of Astronomy, Nanjing University, Nanjing, China
Y. X. Zhang
Affiliation:
Department of Astronomy, Nanjing University, Nanjing, China
M. D. Ding
Affiliation:
Department of Astronomy, Nanjing University, Nanjing, China
W. C. Livingston
Affiliation:
National Solar Observatory, Tucson, AZ85726-6732, USA

Abstract

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CaII K line has been measured regularly nearly every month since 1974 at Kitt Peak. Our study on the data of CaII K profiles over two solar cycles indicates that in center disc spectra, the distance of the K1 component of the CaII K line from the line center and its intensity show periodical variations, but has a time delay of 1.2 years with respect to the sunspot number. Non-LTE computation implies a cyclic temperature variation of about 17 K of the temperature minimum region (TMR) in the quiet-Sun atmosphere and a cyclic variation of about 15-20 km of the position of the TMR.

Type
Session IV: Structure and Dynamics of the Transiton Region and Corona
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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