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      https://www.ias.ac.in/article/fulltext/joaa/042/0075

    • Keywords

       

      Sun: rotation–sunspots; methods: data analysis.

    • Abstract

       

      It is necessary to better understand the dynamic process of solar differential rotation. Here the hand-drawing sunspot group records from 1958 to 2015 of Yunnan Observatories (YNAO) are used to study the solar rotation profile. Firstly, the rotation profile in each solar cycle 19-23 is calculated. Secondly, therotation parameters (equatorial rotation velocity A and differential gradient B) of YNAO are compared with the well-known earlier results. Finally, the rotation parameters in the northern and southern hemispheres during each solar cycle 19-23 are summarized. The main conclusions we reached are as follows: (1) The average difference of the equatorial rotation velocity and differential gradient, between YNAO sunspot and other sunspot datasets, are 0.09 and 0.4, respectively. (2) The magnitudes of the gradient B in the northern hemisphere are larger than that in the southern hemisphere at even-number cycles, and it will approximately reverse at odd-number cycles.

    • Author Affiliations

       

      XIAO-YU LUO1 YANG PENG1 2 SHENG ZHENG1 SHU-GUANG ZENG1 LIN-HUA DENG2 3 YONG-LI FENG2 JIN-PING TAO2

      1. College of Science, China Three Gorges University, Yichang 443002, China.
      2. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216, China.
      3. Chongqing University of Arts and Sciences, Chongqing 402160, China.
    • Dates

       
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