论文标题

Farnet-II:改进的太阳能远侧活动区域检测方法

FarNet-II: An improved solar far-side active region detection method

论文作者

Broock, E. G., Ramos, A. Asensio, Felipe, T.

论文摘要

语境。通过使用诸如相移敏感全息图等热震技术在近侧检测到的地震振荡,通常研究太阳远端的活性。最近,开发了神经网络FARNET来改善这些检测。目标。我们旨在创建一种新的机器学习工具Farnet II,该工具进一步增加了Farnet的范围,并与Farnet和用于检测远侧活动的标准Helioseiss方法相比,评估了其性能。方法。我们开发了Farnet II,这是一个神经网络,它保留了Farnet的一些一般特征,但总体上可以改善检测以及连续预测之间的时间连贯性。主要的新颖性是实施注意力和卷积长期记忆(Convlstm)模块。跨验证方法,使用每次运行的不同验证集培训37次,以利用有限的可用数据。我们使用三年的极端紫外线观测来评估Farnet II的性能,以太阳陆地关系天文台(Stereo)作为活动的代理。将Farnet II的结果与从Farnet获得的结果以及使用骰子系数作为度量的标准Helioseasic方法进行了比较。结果。 Farnet II达到了一个骰子系数,该系数将FARNET的每个输出位置从评估日期提高了0.2分。在标准方法上,其对Farnet的改进高于Farnet。结论。新网络是一种非常有前途的工具,用于改善纯热震动技术给出的太阳远端的活动的检测。太空天气预测可能会受益于这种新方法提供的较高灵敏度。

Context. Activity on the far side of the Sun is routinely studied through the analysis of the seismic oscillations detected on the near side using helioseismic techniques such as phase shift sensitive holography. Recently, the neural network FarNet was developed to improve these detections. Aims. We aim to create a new machine learning tool, FarNet II, which further increases the scope of FarNet, and to evaluate its performance in comparison to FarNet and the standard helioseismic method for detecting far side activity. Methods. We developed FarNet II, a neural network that retains some of the general characteristics of FarNet but improves the detections in general, as well as the temporal coherence among successive predictions. The main novelties are the implementation of attention and convolutional long short term memory (ConvLSTM) modules. A cross validation approach, training the network 37 times with a different validation set for each run, was employed to leverage the limited amount of data available. We evaluate the performance of FarNet II using three years of extreme ultraviolet observations of the far side of the Sun acquired with the Solar Terrestrial Relations Observatory (STEREO) as a proxy of activity. The results from FarNet II were compared with those obtained from FarNet and the standard helioseismic method using the Dice coefficient as a metric. Results. FarNet II achieves a Dice coefficient that improves that of FarNet by over 0.2 points for every output position on the sequences from the evaluation dates. Its improvement over FarNet is higher than that of FarNet over the standard method. Conclusions. The new network is a very promising tool for improving the detection of activity on the far side of the Sun given by pure helioseismic techniques. Space weather forecasts can potentially benefit from the higher sensitivity provided by this novel method.

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