Filtering techniques to enhance optical turbulence forecast performances at short time-scales
Filtering techniques to enhance optical turbulence forecast performances at short time-scales
复制标题
增强短时间尺度光学湍流预测性能的滤波技术
DOI：
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发表时间：
2019
影响因子：
4.8
通讯作者：
A. Turchi
中科院分区：
文献类型：
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作者：
E. Masciadri;G. Martelloni;A. Turchi
自适应光学（AO）支持的一流地基天文设施的管理效率依赖于我们对光学湍流（OT）和一组相关大气参数的预测能力。事实上，尽管AO能够实现，目前，优秀的波前校正水平（Strehl比高达90%，在H波段），其性能在很大程度上取决于大气条件。提前知道大气湍流条件允许AO使用的优化。已经证明，利用OT（${C_N^2 }$）廓线和视宁度、等晕角、波前相干时间等综合天文气候参数，可以提供可靠的预报。第二天晚上在本文中，我们证明，它是可能的，以提高预测性能较短的时间尺度（1或2小时的顺序）与一致的增益（2-8的顺序）采用过滤技术，利用实时测量。这使我们能够实现以前从未获得过的预测精度，并达到天文应用的一个基本里程碑。1或2小时的时间尺度是有效管理天文台支持的地面望远镜的最关键的时间尺度。我们实现了这种方法的业务预测系统的大型双目望远镜（LBT），命名为先进的LBT湍流和大气（阿尔塔）中心，这是在我们所知的，第一个业务系统提供预测的湍流和大气参数在短时间尺度，以支持科学操作。
The efficiency of the management of top-class ground-based astronomical facilities supported by adaptive optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in spite of the fact that the AO is able to achieve, at present, excellent levels of wavefront corrections (a Strehl ratio up to 90 per cent in H band), its performances strongly depend on the atmospheric conditions. Knowing in advance the atmospheric turbulence conditions allows an optimization of the AO use. It has already been proven that it is possible to provide reliable forecasts of the OT (${C_N^2 }$ profiles and integrated astroclimatic parameters such as seeing, isoplanatic angle, wavefront coherence time, etc.) for the next night. In this paper, we prove that it is possible to improve the forecast performances on shorter time-scales (order of 1 or 2 h) with consistent gains (order of 2–8) employing filtering techniques that make use of real-time measurements. This has permitted us to achieve forecasts accuracies never obtained before and reach a fundamental milestone for the astronomical applications. The time-scale of 1 or 2 h is the most critical one for an efficient management of the ground-based telescopes supported by AO. We implemented this method in the operational forecast system of the Large Binocular Telescope (LBT), named Advanced LBT Turbulence and Atmosphere (ALTA) Center that is, at our knowledge, the first operational system providing forecasts of turbulence and atmospheric parameters at short time-scales to support science operations.