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Variations of the solar UV irradiance are an important driver of chemical and physical processes in the Earth's upper atmosphere and may also influence global climate. Here we reconstruct solar UV irradiance in the range 115-400 nm over the…

Solar and Stellar Astrophysics · Physics 2009-11-23 N. A. Krivova , S. K. Solanki , T. Wenzler , B. Podlipnik

In this paper we present new optimization strategies for the reconstruction of X-ray images of solar flares by means of the data collected by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The imaging concept of the…

Instrumentation and Methods for Astrophysics · Physics 2014-06-26 S. Bonettini , M. Prato

This paper contributes to the field of modeling and hindcasting of the total solar irradiance (TSI) based on different proxy data that extend further back in time than the TSI that is measured from satellites. We introduce a simple method…

Solar and Stellar Astrophysics · Physics 2017-03-22 Jaan Pelt , Maarit Käpylä , Nigul Olspert

Modern-day seismic imaging and monitoring technology increasingly rely on dense full-azimuth sampling. Unfortunately, the costs of acquiring densely sampled data rapidly become prohibitive and we need to look for ways to sparsely collect…

Optimization and Control · Mathematics 2020-04-22 Yijun Zhang , Shashin Sharan , Oscar Lopez , Felix J. Herrmann

Surface solar irradiance (SSI) plays a crucial role in tackling climate change - as an abundant, non-fossil energy source, exploited primarily via photovoltaic (PV) energy production. With the growing contribution of SSI to total energy…

Atmospheric and Oceanic Physics · Physics 2023-12-20 Alberto Carpentieri , Doris Folini , Jussi Leinonen , Angela Meyer

For short-term solar irradiance forecasting, the traditional point forecasting methods are rendered less useful due to the non-stationary characteristic of solar power. The amount of operating reserves required to maintain reliable…

Machine Learning · Computer Science 2023-08-02 Sakshi Mishra , Praveen Palanisamy

Reconstructions of solar spectral irradiance - especially in the ultraviolet (UV) range - are crucial for understanding Earth's climate system. Although total solar irradiance (TSI) has been thoroughly investigated, the spectral composition…

Suppressing the interference of atmospheric turbulence and obtaining observation data with a high spatial resolution is an issue to be solved urgently for ground observations. One way to solve this problem is to perform a statistical…

Instrumentation and Methods for Astrophysics · Physics 2022-07-04 Hui Liu , Zhenyu Jin , Yongyuan Xiang , Kaifan Ji

Coherent surface scattering imaging (CSSI) is an emerging experimental technique uniquely suited to probing the structure of thin nanostructures. In these experiments, a specimen is placed on a substrate, and a series of X-ray diffraction…

Computational Physics · Physics 2026-04-22 Jeffrey J. Donatelli , Miaoqi Chu , Zixi Hu , Zhang Jiang , Nicholas Schwarz , Jin Wang , James A. Sethian

Context. Solar spectral irradiance (SSI) variability is one of the key inputs to models of the Earth's climate. Understanding solar irradiance fluctuations also helps to place the Sun among other stars in terms of their brightness…

Solar and Stellar Astrophysics · Physics 2019-11-20 R. V. Tagirov , A. I. Shapiro , N. A. Krivova , Y. C. Unruh , K. L. Yeo , S. K. Solanki

Hyperspectral images (HSIs) capture richer spatial-spectral information beyond RGB, yet real-world HSIs often suffer from a composite mix of degradations, such as noise, blur, and missing bands. Existing generative approaches for HSI…

Computer Vision and Pattern Recognition · Computer Science 2026-02-03 Xiangming Wang , Benteng Sun , Yungeng Liu , Haijin Zeng , Yongyong Chen , Jingyong Su , Jie Liu

The sunspot number (SSN), the total solar irradiance (TSI), a TSI reconstruction, and the solar flare index (SFI), are analyzed for long-range persistence (LRP). Standard Hurst analysis yields $H \approx 0.9$, which suggests strong LRP.…

Space Physics · Physics 2015-06-03 Martin Rypdal , Kristoffer Rypdal

Similarity matrix serves as a fundamental tool at the core of numerous downstream machine-learning tasks. However, missing data is inevitable and often results in an inaccurate similarity matrix. To address this issue, Similarity Matrix…

Machine Learning · Computer Science 2024-10-01 Changyi Ma , Runsheng Yu , Xiao Chen , Youzhi Zhang

We present a new iterative rotation inversion technique based on the Simultaneous Algebraic Reconstruction Technique developed for image reconstruction. We describe in detail our algorithmic implementation and compare it to the classical…

Solar and Stellar Astrophysics · Physics 2024-06-17 Sylvain G. Korzennik , Antonio Eff-Darwich

Cardiac Magnetic Resonance Imaging (MRI) is time-consuming and error-prone. To ease the patient's burden and to increase the efficiency and robustness of cardiac exams, interest in methods based on continuous steady-state acquisition and…

Medical Physics · Physics 2020-10-06 Sebastian Rosenzweig , Nick Scholand , H. Christian M. Holme , Martin Uecker

The spectral energy distribution (SED) of a galaxy contains information on the galaxy's physical properties, and multi-wavelength observations are needed in order to measure these properties via SED fitting. In planning these surveys,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Viviana Acquaviva , Eric Gawiser , Steven J. Bickerton , Norman A. Grogin , Yicheng Guo , Seong-Kook Lee

The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency…

Astrophysics · Physics 2009-11-11 Eduard P. Kontar , Alexander L. MacKinnon

Solar thermal systems (STS) present a promising avenue for low-carbon heat generation, with a well-running system providing heat at minimal cost and carbon emissions. However, STS can exhibit faults due to improper installation,…

Systems and Control · Electrical Eng. & Systems 2025-11-14 Florian Ebmeier , Nicole Ludwig , Jannik Thuemmel , Georg Martius , Volker H. Franz

Due to non-homogeneous mass distribution and non-uniform velocity rate inside the Sun, the solar outer shape is distorted in latitude. In this paper, we analyze the consequences of a temporal change in this figure on the luminosity. To do…

Solar and Stellar Astrophysics · Physics 2011-08-31 Z. Fazel , J. P. Rozelot , S. Lefebvre , A. Ajabshirizadeh , S. Pireaux