We study the solar-cycle variation of subsurface flows for both active and quiet solar regions. We derive flows from the surface to a depth of 16 Mm using ring-diagram analysis applied to Dopplergrams obtained with the Michelson Doppler Imager (MDI) Dynamics Program, the Global Oscillation Network Group (GONG), and the Helioseismic and Magnetic Imager (HMI) instrument. We derive the temporal variation of the zonal and meridional flows in a consistent manner for Solar Cycles 23 and 24 combining the flows from the three data sources scaled to match HMI-derived flows. The subsurface flows associated with active and quiet regions show the same variation with the solar cycle with alternating bands of faster- and slower-than-average zonal and meridional flows moving from mid-latitudes toward the equator during the course of a cycle. We derive the differences between the amplitudes of the extrema of the fast and the slow flows. For Cycle 24, the average difference between the fast- and slow-flow amplitude is 9.5 ± 0.5 m s − 1 $9.5 \pm 0.5~\text{m}\,\text{s}^{-1}$ for the zonal flows and 7.0 ± 0.4 m s − 1 $7.0 \pm 0.4~\text{m}\,\text{s}^{-1}$ for the meridional flows of the quiet-region subset averaged over 2 to 12 Mm within ± 30 ∘ $\pm 30^{\circ}$ latitude. For the active-region subset, the average difference is 10.4 ± 0.9 m s − 1 $10.4 \pm 0.9~\text{m}\,\text{s}^{-1}$ for the zonal flows and 9.3 ± 0.7 m s − 1 $9.3 \pm 0.7~\text{m}\,\text{s}^{-1}$ for the meridional flows. We subtract the flows of the quiet-region subset from those of the active-region one to determine the contribution of active regions to the long-term flow pattern. The resulting meridional flow associated with active regions has a maximum amplitude near 3.1 Mm and its amplitude decreases with depth. This implies that the converging flows attributed to active regions are a shallow-layer phenomenon.

中文翻译：

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活跃区和安静区子集地下流的太阳周期变化

我们研究了活跃和安静的太阳区域的地下流动的太阳周期变化。我们使用环形图分析推导出从表面到 16 毫米深度的流量，该分析应用于通过迈克尔逊多普勒成像仪 (MDI) 动力学程序、全球振荡网络组 (GONG) 以及日震和磁成像仪 (HMI) 获得的多普勒图乐器。对于太阳周期 23 和 24，我们以一致的方式推导出纬向流和经向流的时间变化，结合来自三个数据源的流，这些数据源经过缩放以匹配 HMI 导出的流。与活跃和安静区域相关的地下流显示出与太阳周期相同的变化，在周期过程中，比平均速度快和慢的纬向和经向流交替带移动到赤道。我们推导出快流和慢流的极值幅度之间的差异。对于周期 24，快流和慢流振幅之间的平均差异为 9.5 ± 0.5 ms − 1 $9.5 \pm 0.5~\text{m}\,\text{s}^{-1}$ 对于纬向流和 7.0 ± 0.4 ms − 1 $7.0 \pm 0.4~\text{m}\,\text{s}^{-1}$ 用于静区子集的子午流平均在 ± 30 ∘ 内超过 2 到 12 Mm $\pm 30^{\circ}$ 纬度。对于活动区域子集，区域流的平均差异为 10.4 ± 0.9 ms − 1 $10.4 \pm 0.9~\text{m}\,\text{s}^{-1}$ 和 9.3 ± 0.7 ms − 1 $9.3 \pm 0.7~\text{m}\,\text{s}^{-1}$ 用于子午流。我们从活跃区域的流量中减去安静区域子集的流量，以确定活跃区域对长期流动模式的贡献。由此产生的与活动区相关的经向流在 3.1 毫米附近具有最大振幅，并且其振幅随着深度而减小。这意味着归因于活性区域的会聚流是一种浅层现象。