Science. 1979 Jul 6;205(4401):74-6. doi: 10.1126/science.205.4401.74.
Ultraviolet images of Venus over a 3-month period show marked evolution of the planetary scale features in the cloud patterns. The dark horizontal Y feature recurs quasi-periodically, at intervals of about 4 days, but it has also been absent for periods of several weeks. Bow-shaped features observed in Pioneer Venus images are farther upstream from the subsolar point than those in Mariner 10 images.
在三个月的时间内，金星的紫外线图像显示出云模式中行星尺度特征的明显演变。黑暗的水平 Y 特征近乎周期性地出现，间隔约为 4 天，但也有几周没有出现。与水手 10 号图像相比，先驱者金星图像中观测到的弓形特征更靠近太阳点的上游。
