Principal components of short-term variability in the ultraviolet albedo of Venus
Principal components of short-term variability in the ultraviolet albedo of Venus
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DOI：
10.1051/0004-6361/201935388
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发表时间：
2019-06-06
影响因子：
6.5
通讯作者：
Yamazaki, Atsushi
中科院分区：
文献类型：
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作者：
Kopparla, Pushkar;Lee, Yeon Joo;Yamazaki, Atsushi
我们探索的主要模式的变化，在所观察到的太阳能在金星云顶使用Akatsuki紫外线283 nm和365 nm的观测，这是敏感的SO2和未知的紫外线吸收剂分布分别。这些观测是在2016年12月至2018年5月期间进行的，包括金星白天的图像，通常每隔两个小时观测一次，但其间穿插着较长的间隙。航天器的轨道不允许对整个昼面进行连续观测，未观测到的区域导致数据集出现重大缺口。每个数据集被细分为三个子集的三个观察期，未观察到的数据进行插值，然后对每个子集进行主成分分析，以找到六个振荡模式的周期。在所有三个时期的主成分在283 nm处显示出相似的形态，但在365 nm处变化更大。这些模式的一些空间模式和时间尺度对应于金星大气中众所周知的物理过程，例如类似于4天开尔文波，5天Rossby波和翻转环流，而其他模式则无法简单解释。我们还发现了一个尚未被很好理解的半球模式，并讨论了它的含义。
We explore the dominant modes of variability in the observed albedo at the cloud tops of Venus using Akatsuki UVI 283 nm and 365 nm observations, which are sensitive to SO2 and unknown UV absorber distributions respectively. The observations, taken over the period Dec. 2016 to May 2018, consist of images of the dayside of Venus, most often observed at intervals of two hours, but interspersed with longer gaps. The orbit of the spacecraft does not allow for continuous observation of the full dayside and the unobserved regions cause significant gaps in the datasets. Each dataset is subdivided into three subsets for three observing periods, the unobserved data are interpolated, and each subset is then subjected to a principal component analysis to find six oscillating patterns in the albedo. Principal components in all three periods show similar morphologies at 283 nm, but are much more variable at 365 nm. Some spatial patterns and the timescales of these modes correspond to well-known physical processes in the atmosphere of Venus such as the similar to 4-day Kelvin wave, 5-day Rossby waves, and the overturning circulation, while others defy a simple explanation. We also a find a hemispheric mode that is not well understood and discuss its implications.