Mars: Abundant Recurring Slope Lineae (RSL) Following the Planet‐Encircling Dust Event (PEDE) of 2018
Mars: Abundant Recurring Slope Lineae (RSL) Following the Planet‐Encircling Dust Event (PEDE) of 2018
复制标题
火星：2018 年环行星尘埃事件 (PEDE) 后出现丰富的循环坡线 (RSL)
DOI：
10.1029/2020je006575
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
M. Chojnacki
中科院分区：
文献类型：
--
作者：
A. McEwen;E. Schaefer;C. Dundas;S. Sutton;L. Tamppari;M. Chojnacki
周期性斜坡线（RSL）是火星上每年再生的深色线性标记，可能来自液态水或颗粒物质的流动。在火星年（MY）34的大沙尘暴（或行星环绕尘埃事件，PEDE）之后，火星侦察轨道器/高分辨率成像科学实验已经看到了比典型火星年更多的候选RSL。从2018年8月（当大气随着PEDE衰减而变清时）到2019年8月，它们在超过285个独特的位置进行了成像，其中大约一半（157）是以前没有记录的RSL位置。在MY 34中，在南中纬度（SML，-60 °至-30 °）确定了150个活跃的RSL站点，而在MY 28 -33中，每年平均观察到36个活跃站点。与往年相比，PEDE后的RSL在南部夏季也出现在更广泛的纬度，坡度和Ls（太阳的地心经度）范围内。这些RSL站点通常显示出最近尘埃沉积的证据：相对黑暗的区域变得模糊，整体比往年更亮更红的表面，以及沙尘暴轨迹，这表明尘埃通过几种机制提升。我们推测，尘埃抬升过程可能会启动和维持RSL活动。RSL可能是由灰尘（可能是结块的）和/或沙子的流动形成的，这些流动被灰尘运动或直接被沙尘暴移动而不稳定。如果是这样的话，那么RSL活动的令人困惑的复发和逐年变化至少可以部分解释。沙尘补充量的年际变化可以解释RSL活动的年际变化。
Recurring slope lineae (RSL) are dark linear markings on Mars that regrow annually and likely originate from the flow of either liquid water or granular material. Following the great dust storm (or planet‐encircling dust event, PEDE) of Mars year (MY) 34, Mars Reconnaissance Orbiter/High Resolution Imaging Science Experiment has seen many more candidate RSL than in typical Mars years. They have been imaged at more than 285 unique locations from August 2018 (when the atmosphere was clearing as the PEDE decayed) to August 2019, about half (157) of which are locations where RSL have not been documented previously. In MY34, 150 active RSL sites were identified in the southern middle latitudes (SML, ‐60° to ‐30°), whereas an average of 36 active sites were observed in each previous year (MY28–33). Post‐PEDE RSL are also present during southern summer over a wider range of latitude, slope aspect, and Ls (areocentric longitude of the sun) than in prior years. These RSL sites usually show evidence for recent dust deposition: obscuration of relatively dark areas, an overall brighter and redder surface than in prior years, and dust devil tracks, which indicate dust lifting by several mechanisms. We speculate that dust‐lifting processes may initiate and sustain RSL activity. The RSL may form from flows of dust (perhaps clumped) and/or sand that is destabilized by dust movement or directly mobilized by dust devils. If this is the case, then the otherwise puzzling recurrence and year‐to‐year variability of RSL activity can be at least partly explained. The dust replenishment varies from year to year, which could explain interannual variations in RSL activity.
影响因子：
10.3
作者：
L. Neakrase;M. Balme;F. Esposito;T. Kelling;M. Klose;J. Kok;B. Marticorena;J. Merrison;M. Patel;G. Wurm
通讯作者：
L. Neakrase;M. Balme;F. Esposito;T. Kelling;M. Klose;J. Kok;B. Marticorena;J. Merrison;M. Patel;G. Wurm