Spectroscopic observations at extreme- and far-ultraviolet wavelengths have revealed systematic upflows in the solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of active regions, and dimming regions associated with coronal mass ejections. They have been intensively studied in the past two decades because they are likely to be closely related to the formation of the solar wind and heating of the upper solar atmosphere. We present an overview of the characteristics of these upflows, introduce their possible formation mechanisms, and discuss their potential roles in the mass and energy transport in the solar atmosphere. Although past investigations have greatly improved our understanding of these upflows, they have left us with several outstanding questions and unresolved issues that should be addressed in the future. New observations from the Solar Orbiter mission, the Daniel K. Inouye Solar Telescope, and the Parker Solar Probe will likely provide critical information to advance our understanding of the generation, propagation, and energization of these upflows.

在极紫外和远紫外波长的光谱观察表明，在太阳过渡区和日冕中有系统的上流。在安静的太阳和日冕孔的网络结构，活动区域的边界以及与日冕物质抛射相关的变暗区域中，可以最好地看到这些上流。在过去的二十年中，对它们进行了深入的研究，因为它们可能与太阳风的形成和高层太阳大气的加热密切相关。我们概述了这些上升流的特征，介绍了它们可能的形成机制，并讨论了它们在太阳大气中质量和能量传输中的潜在作用。尽管过去的调查大大提高了我们对这些流量的理解，他们给我们留下了一些悬而未决的问题和未解决的问题，这些问题应在将来解决。来自的新观察太阳轨道飞行器任务，Daniel K. Inouye太阳望远镜和帕克太阳探测器将可能提供重要信息，以加深我们对这些上升流的产生，传播和激励的理解。