Orton Glenn S, Tabataba-Vakili Fachreddin, Eichstädt Gerald, Rogers John, Hansen Candice J, Momary Thomas W, Ingersoll Andrew P, Brueshaber Shawn, Wong Michael H, Simon Amy A, Fletcher Leigh N, Ravine Michael, Caplinger Michael, Smith Dakota, Bolton Scott J, Levin Steven M, Sinclair James A, Thepenier Chloe, Nicholson Hamish, Anthony Abigail
Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA.
Independent Scholar Stuttgart Germany.
J Geophys Res Planets. 2020 Jul;125(7):e2019JE006369. doi: 10.1029/2019JE006369. Epub 2020 Jun 28.
In the first 20 orbits of the Juno spacecraft around Jupiter, we have identified a variety of wave-like features in images made by its public-outreach camera, JunoCam. Because of Juno's unprecedented and repeated proximity to Jupiter's cloud tops during its close approaches, JunoCam has detected more wave structures than any previous surveys. Most of the waves appear in long wave packets, oriented east-west and populated by narrow wave crests. Spacing between crests were measured as small as ~30 km, shorter than any previously measured. Some waves are associated with atmospheric features, but others are not ostensibly associated with any visible cloud phenomena and thus may be generated by dynamical forcing below the visible cloud tops. Some waves also appear to be converging, and others appear to be overlapping, possibly at different atmospheric levels. Another type of wave has a series of fronts that appear to be radiating outward from the center of a cyclone. Most of these waves appear within 5° of latitude from the equator, but we have detected waves covering planetocentric latitudes between 20°S and 45°N. The great majority of the waves appear in regions associated with prograde motions of the mean zonal flow. Juno was unable to measure the velocity of wave features to diagnose the wave types due to its close and rapid flybys. However, both by our own upper limits on wave motions and by analogy with previous measurements, we expect that the waves JunoCam detected near the equator are inertia-gravity waves.
在朱诺号航天器环绕木星的前20个轨道中，我们在其公众宣传相机朱诺相机拍摄的图像中识别出了各种波状特征。由于朱诺号在近距离飞越期间前所未有的、反复靠近木星云顶，朱诺相机探测到的波结构比以往任何调查都要多。大多数波出现在长波包中，呈东西向排列，由狭窄的波峰组成。波峰之间的间距经测量小至约30千米，比以往测量的任何间距都短。一些波与大气特征有关，但其他一些波表面上与任何可见的云现象都没有关联，因此可能是由可见云顶以下的动力强迫产生的。一些波似乎在汇聚，而其他一些波似乎在重叠，可能发生在不同的大气高度。另一种类型的波有一系列锋面，似乎从一个气旋中心向外辐射。这些波大多出现在距离赤道5°以内的纬度范围内，但我们也探测到了覆盖行星中心纬度在南纬20°至北纬45°之间的波。绝大多数波出现在与平均纬向流的正向运动相关的区域。由于朱诺号近距离快速飞越，无法测量波特征的速度来诊断波的类型。然而，通过我们自己对波运动的上限以及与以往测量的类比，我们预计朱诺相机在赤道附近探测到的波是惯性重力波。
