with a spatial resolution of 0$\farcs$5 per pixel, with the cadences of the three former channels being about 45 s and that of the latter one being about 12 minutes.

Methods
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We calculate the negative magnetic flux and the change rate of magnetic flux as in the flowing equations: $$\label{eqflux}
    \phi = \int B_{zn} dA,$$ and $$\label{rate}
    r = \frac{d|\phi|}{dt},$$ in which $B_{zn}$ denotes the negative magnetic field, A is the integrative areas and t is the time.

According to the Ampere’s law, the current density can be derived by follow equation: $$\label{eq1}
    \textbf{J} = \frac{1}{\mu_0}(\bigtriangledown \times \textbf{B}),$$ in which $\mu_0$ is the magnetic permeability of vacuum and **B** is the magnetic field vector. Therefore, the vertical current density perpendicular to the solar surface, can be calculated by using the $SDO$/HMI VMs data. Based on the equation: $$\label{eq2}
    j_z = \frac{1}{\mu_0}(\bigtriangledown \times \textbf{B})_z = \frac{1}{\mu_0}(\frac{\partial B_y}{\partial x} - \frac{\partial B_x}{\partial y}),$$ where $B_x$ and $B_y$ are the two perpendicular components of the transverse magnetic fields. With the data from $SDO$/HMI VMs, the distribution of $j_z$ on the solar surface can be obtained every 12 minutes. Therefore, the vertical current can be integrated by the vertical current density in the 