Advances in Space Research最新文献_第2页

IonoNet: a European network of oblique ionosondes 离子网：欧洲斜向电离探空网

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.12.019

Achille Zirizzotti , Umberto Sciacca , Enrico Zuccheretti , Carlo Scotto , Loredana Perrone , James Arokiasamy Baskaradas

IonoNet is an INGV (Istituto Nazionale di Geofisica e Vulcanologia) research project developing a multi-static cooperative radar network of Pseudo-Random Code (PRC) ionosondes deployed across Europe. This innovative approach enables oblique soundings to compare ionospheric characteristics over vast distances. The project develops ionosondes for both oblique and vertical soundings, supported by a complete data analysis pipeline. A key feature is the real-time processing capability, which transforms oblique into vertical ionograms, generates electron density profiles using Autoscala program, and can issue ionospheric alerts under disturbed conditions.

The system’s core innovation is its reliance on Software Defined Radio (SDR) devices for both transmission and reception. This SDR-based architecture provides significant versatility, allowing for flexible configuration of transmission parameters and signal filtering via software, replacing complex traditional hardware.

A primary novelty is the network’s multi-static capability: a single receiving observatory can simultaneously detect signals from multiple transmitters. This “many-to-one” approach multiplies the observational viewpoints. The system uses unique station identifiers and precise GPS synchronization (GPSDO − GPS Disciplined Oscillator) to manage these complex, simultaneous soundings.

Ultimately, this advanced sounding network enables large-scale ionospheric mapping, validation of global models, and the study of local disturbances, space weather impacts, and potential ionosphere-lithosphere coupling.

IonoNet是INGV （Istituto Nazionale di Geofisica e Vulcanologia）的一个研究项目，旨在开发一个多静态的伪随机码（PRC）离子探空仪合作雷达网络，部署在欧洲各地。这种创新的方法使倾斜探测能够比较远距离的电离层特征。该项目开发了用于倾斜和垂直探测的电离层探空仪，并由完整的数据分析管道提供支持。其关键特点是实时处理能力，可以将倾斜电离层图转换为垂直电离层图，使用Autoscala程序生成电子密度分布图，并可以在干扰条件下发出电离层警报。该系统的核心创新在于它对软件定义无线电（SDR）设备的依赖，用于传输和接收。这种基于sdr的架构提供了显著的多功能性，允许通过软件灵活配置传输参数和信号滤波，取代了复杂的传统硬件。一个主要的新颖之处是网络的多静态能力：单个接收天文台可以同时检测来自多个发射机的信号。这种“多对一”的方法增加了观察视点。该系统使用独特的站标识符和精确的GPS同步（GPSDO - GPS纪律振荡器）来管理这些复杂的，同时探测。最终，这个先进的探测网络能够实现大规模电离层测绘、全球模型验证、局部扰动、空间天气影响和潜在电离层-岩石圈耦合的研究。

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引用次数: 0

Designing observer-based adaptive multi-model predictive attitude control for flexible satellites 基于观测器的柔性卫星自适应多模型预测姿态控制设计

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.042

Mohammad Fathi , Hossein Bolandi , Bahman Ghorbani Vaghei

The complexity of attitude control for flexible satellites surpasses that of rigid satellites due to factors such as oscillations of flexible appendages, uncertainties in moment of inertia, and unmeasurable modal variables. This paper investigates the design of an observer-based multi-model predictive controller for the attitude control of a flexible satellite. In this context, the development of an appropriate observer capable of estimating the lumped impact of disturbances resulting from moment of inertia uncertainty, modal variables, and external perturbations in flexible satellites has been discussed, with a focus on ensuring its asymptotic convergence. Furthermore, to establish the optimal model bank within the multi-model control framework, a novel PSO-based automatic clustering approach has been employed. Subsequently, the design of the adaptive model predictive controller bank is presented, accompanied by a supervisor algorithm that enables seamless soft switching to uphold the asymptotic stability of the closed-loop system. Through simulation study, the efficacy of the proposed control system is assessed, demonstrating the attainment of high attitude control accuracy for flexible satellites.

由于柔性附件的振荡、转动惯量的不确定性和模态变量的不可测性等因素，柔性卫星姿态控制的复杂性超过刚性卫星。研究了基于观测器的柔性卫星姿态控制多模型预测控制器的设计。在这种情况下，讨论了开发一种适当的观测器的问题，该观测器能够估计柔性卫星中由惯性矩不确定性、模态变量和外部扰动引起的扰动的集中影响，重点是确保其渐近收敛。此外，为了在多模型控制框架内建立最优模型库，采用了一种新颖的基于粒子群算法的自动聚类方法。随后，提出了自适应模型预测控制器组的设计，并提出了一种监督算法，实现了无缝软切换，以保持闭环系统的渐近稳定性。通过仿真研究，对所提出的控制系统的有效性进行了评估，表明该控制系统实现了对柔性卫星的高姿态控制精度。

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引用次数: 0

Attention enhanced ResNet for ocean surface wind speed retrieval using CYGNSS observables 注意增强ResNet利用CYGNSS观测资料检索海面风速

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.023

Yongchao Zhu , Qiuling Lu , Maorong Ge , Xiaochuan Qu , Tingye Tao , Kegen Yu , Shuiping Li

Global Navigation Satellite System Reflectometry (GNSS-R) has emerged as a pivotal technique for ocean surface wind speed retrieval; however, establishing robust multi-parameter retrieval models remains challenging due to the nonlinear relationships between GNSS-R observables and geophysical variables. An Attention-enhanced Residual Network (Att-ResNet) is proposed to address this challenge, leveraging Cyclone Global Navigation Satellite System (CYGNSS) bistatic radar data for wind speed estimation. The CYGNSS datasets were processed to extract multi-parameter observables, including Delay-Doppler Maps (DDMs), normalized bistatic radar cross-section (NBRCS), and incidence angle, which served as inputs for training wind speed retrieval models using diverse backbone architectures (e.g., ResNet and AlexNet). Ablation experiments employing the Att-ResNet framework were systematically conducted, with ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis 5) and CCMP (Cross-Calibrated Multi-Platform) wind products providing benchmark validation. Comparative analysis revealed that the Att-ResNet-retrieved wind speeds exhibited strong spatiotemporal consistency with ERA5 and CCMP data. Quantitative evaluations showed root mean square errors (RMSEs) of 1.379 m/s (ERA5) and 1.390 m/s (CCMP), with minimal biases (−0.069 m/s and −0.014 m/s, respectively) and unbiased RMSEs (ubRMSEs) of 1.377 m/s and 1.390 m/s. The study demonstrates that the Att-ResNet architecture, through its attention-driven feature selection and residual learning mechanisms, significantly enhances spaceborne GNSS-R wind retrieval accuracy. This artificial intelligence-driven framework establishes a new paradigm for high-resolution spatiotemporal ocean surface wind monitoring, demonstrating the transformative potential of deep learning in advancing GNSS-R applications.

全球导航卫星系统反射测量（GNSS-R）已成为海洋表面风速反演的关键技术。然而，由于GNSS-R观测值与地球物理变量之间的非线性关系，建立鲁棒的多参数检索模型仍然具有挑战性。为了应对这一挑战，提出了一个注意力增强剩余网络（Att-ResNet），利用气旋全球导航卫星系统（CYGNSS）双基地雷达数据进行风速估计。对CYGNSS数据集进行处理，提取多参数观测数据，包括延迟多普勒图（DDMs）、归一化双基地雷达截面（NBRCS）和入射角，并将其作为使用不同主干架构（如ResNet和AlexNet）训练风速检索模型的输入。采用at - resnet框架系统地进行了消融实验，ERA5（欧洲中期天气预报再分析中心5）和CCMP（交叉校准多平台）风力产品提供基准验证。对比分析表明，at - resnet反演的风速与ERA5和CCMP数据具有较强的时空一致性。定量评价结果显示，均方根误差（rmse）为1.379 m/s （ERA5）和1.390 m/s (CCMP)，偏差最小（分别为- 0.069 m/s和- 0.014 m/s），无偏均方根误差（ubRMSEs）为1.377 m/s和1.390 m/s。研究表明，at - resnet架构通过其关注驱动的特征选择和残差学习机制，显著提高了星载GNSS-R风反演精度。这个人工智能驱动的框架为高分辨率时空海洋表面风监测建立了一个新的范例，展示了深度学习在推进GNSS-R应用方面的变革潜力。

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引用次数: 0

Understanding urbanization and its expansion process in Bengaluru through geostatistical models for landscape management 基于景观管理地统计模型的班加罗尔城市化及其扩展过程研究

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.018

Ahmed Ali Bindajam , Javed Mallick , Mohammed J. Alshayeb , Sayanti Poddar

Urban sprawl in rapidly growing cities like Bengaluru has emerged as a critical planning challenge, often resulting in fragmented landscapes, ecological degradation, and pressure on infrastructure. This study evaluates the spatial–temporal dynamics of urbanization in Bengaluru from 1994 to 2024 using advanced geospatial modeling techniques. Landsat 4/5 TM and Landsat 8/9 OLI datasets were classified with a Random Forest algorithm, achieving high classification accuracy (overall >90 %, Kappa >0.85). Land Use and Land Cover (LULC) analysis reveals that built-up area increased from 162.35 km² in 1994 to 376.37 km² in 2024 (+31.9 %), while open land declined from 429.08 km² to 210.67 km² (−50.9 %); vegetation fluctuated from 106.86 km² in 1994 to 111.24 km² in 2024, and water bodies decreased from 21.40 km² in 2004 to 11.24 km² in 2024. Change Vector Analysis showed a progressive rise in mean transformation magnitude from 5.4 (1994–2004) to 8.9 (1994–2024). Transition matrices indicate substantial conversions to built-up, with ∼33 % of vegetation and 30 % of water bodies transformed. Spatial pattern indices confirm structural reorganization: the Urban Contiguity Index rose from 0.40 to 0.82, while the Urban Dispersion Index fell from 0.59 to 0.17, alongside an increase in Built-Up Density Index (0.134–0.311) and Edge Density (≈2858–4932). Built-up density intensified (mean 1.21–2.80), with the high-density share expanding (≈21.6–42.2 %). Leapfrogging dominated early growth (LUI = 0.50, 1994–2004), whereas infill strengthened later (IR = 0.37, 2014–2024). These findings provide evidence of a transition from fragmented to more compact growth, underscoring the need for sustainable planning. The integrated framework offers a replicable diagnostic model for urban sprawl in rapidly urbanizing regions of the Global South.

在像班加罗尔这样快速发展的城市，城市扩张已经成为一个重大的规划挑战，往往导致景观破碎、生态退化和基础设施压力。本研究利用先进的地理空间建模技术，对1994 - 2024年班加罗尔城市化的时空动态进行了评价。采用Random Forest算法对Landsat 4/5 TM和Landsat 8/9 OLI数据集进行分类，分类准确率较高（overall >90 %,Kappa >0.85）。土地利用和土地覆盖（LULC）分析表明，建成区面积从1994年的162.35 km2增加到2024年的376.37 km2(+ 31.9% %)，开放地面积从429.08 km2减少到210.67 km2(- 50.9% %)；植被从1994年的106.86 km2波动到2024年的111.24 km2，水体从2004年的21.40 km2减少到2024年的11.24 km2。变化向量分析表明，平均转变幅度从5.4（1994-2004）逐渐上升到8.9（1994-2024）。过渡矩阵表明大量转化为堆积，约33% %的植被和30% %的水体转化为堆积。空间格局指数证实了结构重组：城市邻近度指数从0.40上升到0.82，城市分散度指数从0.59下降到0.17，建成区密度指数（0.134 ~ 0.311）和边缘密度（≈2858 ~ 4932）均有所上升。堆积密度增大（平均1.21 ~ 2.80），高密度占比增大（≈21.6 ~ 42.2 %）。跳跃式增长主导了早期增长（LUI = 0.50,1994-2004），而填充型增长随后加强（IR = 0.37,2014-2024）。这些发现提供了从分散增长向更紧凑增长过渡的证据，强调了可持续规划的必要性。该综合框架为全球南方快速城市化地区的城市蔓延提供了可复制的诊断模型。

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引用次数: 0

Virtual water gauge from the Synthetic Aperture Radar (SAR) altimeters for small reservoirs in tropical regions 基于合成孔径雷达（SAR）高度计的热带小型水库虚拟水位计

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.060

Mohd Adha Abdul Majid , Nurul Hazrina Idris , Mohd Nadzri Md Reba , Stefano Vignudelli

This paper evaluates the performance of Synthetic Aperture Radar (SAR) altimetry from Sentinel-3 for monitoring water surface elevation (WSE) in small reservoirs (<500 km²) in Malaysia. The study area focuses on Kenyir (326.4 km²), Temengor (137.3 km²) and Chenderoh (8.6 km²) reservoirs that have complex tropical landscapes and limited in-situ gauge coverage. Waveform classification reveals dominant (100 %) quasi-specular returns (Class I) at Chenderoh, whereas Kenyir and Temengor show substantial proportions of multi-peak and complex waveforms, requiring enhanced retracking to mitigate land contamination. Six atmospheric and geophysical correction sets are tested, incorporating European Centre for Medium-Range Weather Forecasts (ECMWF) tropospheric models, ocean tide models including the Finite Element Solution 2014 (FES2014), Goddard Ocean Tide model version 4.10 (GOT v4.10), and the TOPEX/Poseidon 9th release ATLAS (TPXO9-ATLAS), as well as geoid models comprising the European Improved Gravity Model EIGEN6C4 (EIGEN6C4) and the Earth Gravitational Model 2008 (EGM2008). The best performing sets are Set 3 and Set 5 for Kenyir, Set 6 for Temengor, and Set 1 and Set 2 for Chenderoh. Correlations with gauge observations exceed 0.95 for all reservoirs (p < 0.05). Root mean square error (RMSE) values are 49 cm (Kenyir), 50 cm (Temengor), and 80 cm (Chenderoh). Normalised RMSE highlights how relative performance depends on reservoir scale: Kenyir and Temengor achieve low relative errors (<7 % of water-level range), while Chenderoh shows higher relative errors (39 %) due to its narrow variability (∼2 m). These findings demonstrate the potential of Sentinel-3 SAR altimetry for monitoring small tropical reservoirs, while emphasising the importance of correction model choice and local reservoir characteristics.

本文评估了Sentinel-3合成孔径雷达（SAR）测高技术在马来西亚小型水库（<500 km2）监测水面高程（WSE）的性能。研究区域主要集中在kenir （326.4 km2）、Temengor （137.3 km2）和Chenderoh （8.6 km2）水库，这些水库具有复杂的热带景观和有限的原位测量覆盖范围。波形分类显示，Chenderoh地区占主导地位（100%）的准镜面回波（I类），而Kenyir和Temengor地区则显示出相当大比例的多峰和复杂波形，需要加强重新跟踪以减轻土地污染。测试了6套大气和地球物理校正集，包括欧洲中期天气预报中心（ECMWF）对流层模型、海潮模型（包括2014年有限元解（FES2014）、戈达德海潮模型4.10版本（GOT v4.10）、TOPEX/Poseidon第9版ATLAS (TPXO9-ATLAS)），以及包括欧洲改进重力模型EIGEN6C4 （EIGEN6C4）和地球引力模型2008 （EGM2008）在内的大地面模型。表现最好的是肯尼亚的第3组和第5组，Temengor的第6组，Chenderoh的第1组和第2组。所有储层与测量值的相关性均超过0.95 （p < 0.05）。均方根误差（RMSE）值分别为49 cm （Kenyir）、50 cm （Temengor）和80 cm （Chenderoh）。标准化RMSE强调了相对性能如何取决于水库规模：肯尼亚和Temengor的相对误差较低（<； 7%的水位范围），而Chenderoh由于变异性较窄（约2米），相对误差较高（39%）。这些发现证明了Sentinel-3 SAR测高在监测小型热带水库方面的潜力，同时强调了校正模式选择和当地水库特征的重要性。

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引用次数: 0

Ionospheric anomalies as potential earthquake precursors: observations over northern India prior to the 17 February 2025, New Delhi and 28 March 2025, Myanmar earthquakes 电离层异常作为潜在的地震前兆：2025年2月17日新德里地震和2025年3月28日缅甸地震前印度北部的观测

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.093

Anshul Singh , Qadeer Ahmed , Aastha Rawat , Ankit Gupta , Arti Bhardwaj , Ashish Ranjan , Puja Goel , Arun Kumar Upadhayaya

We examined the ionospheric response to two recent earthquakes: a magnitude 7.7 event that struck Myanmar’s Sagaing region near Mandalay on 28 March 2025 at 06:20:52 UT, and an earthquake with magnitude 4.0, on 17 February 2025 at 00:06:55 UT (05:36:55 IST) with its epicenter near New Delhi, India. Our analysis uses GPS-derived vertical total electron content (VTEC) data from a network of ground-based IRNSS and GNSS stations—New Delhi (NPL), Pantnagar, Palampur, Lucknow, and Dehradun—along with foF2 and h′F parameters from Digisonde observations and geomagnetic field observations from the Overhauser-effect magnetometer at New Delhi. Distinct ionospheric perturbations were detected 12 days prior to both earthquakes at all stations, suggesting a possible link to seismo-ionospheric coupling. These anomalies, seen as enhancements and depletions in ΔVTEC and ΔfoF2, corresponded to peak electron density variations of ∼244% and ∼201% for the 17 February and 28 March earthquake events, respectively. Geomagnetic and solar conditions remained quiet and stable during February and March 2025, minimising the likelihood of solar influences and supporting a seismic origin for the disturbances. Ionospheric anomalies were detected even for the earthquakes with magnitudes below 6 Mw (where Mw represents moment magnitude), consistent with earlier studies that identified this threshold as significant for observing ionospheric precursor signatures. This study underscores that, in addition to earthquake magnitude, the proximity of the epicenter to the ionospheric monitoring station plays a crucial role in the detectability of such signals. In addition, notable magnetic field variations of approximately −75 nT and −106 nT were recorded a few hours to 2 days prior to the 17 February 2025 and 28 March 2025 earthquakes, respectively. Furthermore, the enhancements observed at all stations between 18 and 20 February 2025 and 5–8 March 2025, were likely influenced by a concurrent sudden stratospheric warming (SSW) event.

我们研究了电离层对最近两次地震的反应：2025年3月28日06:20:52 UT发生在缅甸曼德勒附近实皆地区的7.7级地震，以及2025年2月17日00:06:55 UT （05:36:55 IST）震中位于印度新德里附近的4.0级地震。我们的分析使用了基于gps的垂直总电子含量（VTEC）数据，这些数据来自地面IRNSS和GNSS站点网络——新德里（NPL）、潘特纳格尔、帕拉姆普尔、勒克瑙和德拉敦——以及来自Digisonde观测的foF2和h 'F参数和来自新德里奥弗豪斯效应磁力计的地磁场观测。在两次地震前12天，所有监测站都检测到明显的电离层扰动，这表明地震-电离层耦合可能存在联系。这些异常，在ΔVTEC和ΔfoF2被视为增强和耗尽，对应于2月17日和3月28日地震事件的峰值电子密度变化分别为~ 244%和~ 201%。2025年2月和3月期间，地磁和太阳状况保持安静和稳定，使太阳影响的可能性最小化，并支持这些扰动的地震起源。即使在震级低于6mw（其中Mw表示矩级）的地震中也检测到电离层异常，这与早期的研究一致，该研究认为该阈值对于观察电离层前兆特征具有重要意义。这项研究强调，除了地震震级外，震中与电离层监测站的接近程度在这种信号的可探测性中起着至关重要的作用。此外，在2025年2月17日和2025年3月28日地震发生前几小时至两天，分别记录到约- 75 nT和- 106 nT的显著磁场变化。此外，2025年2月18日至20日和2025年3月5日至8日期间所有台站观测到的增强可能受到同期平流层突然变暖（SSW）事件的影响。

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引用次数: 0

Estimation of SO2 concentration and coupling model of exposure risk based on CatBoost and multiple meteorological parameters 基于CatBoost和多气象参数的SO2浓度估算及暴露风险耦合模型

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.092

XuMing Yang, YaJing Kang, ChunKang Zhang

This study established a multi-parameter inversion framework. The CatBoost model was used to integrate the TROPOMI-L3 SO₂ column concentration from the Sentinel-5P satellite, ERA5 meteorological reanalysis data, and LandScan population distribution data to estimate the near-surface concentration in the Beijing-Tianjin-Hebei (BTH) region. Meanwhile, in view of the limitations of traditional exposure models, a new population exposure risk model was proposed. This model coordinated the estimated sulfur dioxide concentration, population distribution data, and key meteorological parameters to quantify the spatial differentiation characteristics of the population exposure risk in the BTH region in the four seasons of 2019. The spatial autocorrelation method was used to further determine the local risk clustering patterns. The cross-validation results showed that the CatBoost model had higher estimation accuracy than the NGBoost, LightGBM, and XGBoost models (R² = 0.859, RMSE = 2.86 μg∙m⁻³, MAE = 1.89 μg∙m⁻³). At the same time, the distribution maps of sulfur dioxide concentration and exposure risk with high spatio-temporal resolution were drawn, and the spatio-temporal variation trends of sulfur dioxide concentration and exposure risk were analyzed.

本研究建立了一个多参数反演框架。利用CatBoost模型综合Sentinel-5P卫星TROPOMI-L3 SO2柱浓度、ERA5气象再分析资料和LandScan人口分布资料，估算了京津冀地区近地表SO2浓度。同时，针对传统暴露模型的局限性，提出了一种新的人群暴露风险模型。该模型协调估算二氧化硫浓度、人口分布数据和关键气象参数，量化了2019年4个季节BTH地区人口暴露风险的空间分异特征。采用空间自相关法进一步确定局部风险聚类模式。交叉验证结果表明，CatBoost模型的估计精度高于NGBoost、LightGBM和XGBoost模型（R2 = 0.859, RMSE = 2.86 μg∙m−3,MAE = 1.89 μg∙m−3）。同时绘制高时空分辨率二氧化硫浓度和暴露风险分布图，分析二氧化硫浓度和暴露风险的时空变化趋势。

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引用次数: 0

Investigating wind shear theory associated with Sporadic-E layer formation using WACCM-X and HWM models, ionosondes, and radio occultation 利用WACCM-X和HWM模型、电离层探空仪和无线电掩星研究与散散e层形成相关的风切变理论

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.057

Kimiya Masjed Jamei, A. Mahmoudian

Sporadic-E (Es) layers in the ionosphere are shaped by vertical wind shear in the presence of Earth’s magnetic field, which significantly influences their formation by affecting the mobility of metallic ions through the Lorentz force. This study delivers a thorough analysis of vertical ion convergence (VIC) considering relevant factors including the zonal and meridional winds, magnetic inclination and declination angles. Data on neutral winds is obtained from the WACCM-X and HWM models. The study explores the diurnal and seasonal variations in the occurrence of Es layers at six Australian ionosonde sites throughout 2006, leveraging VIC_max data from the model. A comparison of VIC_max time series with ionosonde data from Australia reveals an overall encouraging correlation with empirical model results of Es formation over twelve consecutive months, utilizing foEs data. The temporal evolution of the sporadic-E cloud in areas with available ionosondes is assessed using the VIC amplitude derived from numerical simulations. Evidence suggests that the neutral wind patterns from the HWM model and the framework of wind shear theory can illustrate the annual evolution, spatial extent, and seasonal fluctuations of sporadic-E. Furthermore, the global distribution of sporadic-E, as obtained from radio occultation data for January and July 2014 is investigated. The differing seasonal dependencies of sporadic-E in the summer hemisphere are also analyzed.

电离层中的零星e （Es）层是由地球磁场存在下的垂直风切变形成的，它通过洛伦兹力影响金属离子的迁移率，从而显著影响电离层的形成。本文综合考虑了纬向风、经向风、地磁倾角和磁偏角等因素，对垂直离子辐合（VIC）进行了深入分析。中性风的数据来自WACCM-X和HWM模式。该研究利用该模式的VICmax数据，探讨了2006年澳大利亚六个电离层监测站Es层发生的日变化和季节变化。VICmax时间序列与澳大利亚电离层探空仪数据的比较显示，利用foe数据，在连续12个月的时间里，与经验模型结果的Es形成总体上令人鼓舞的相关性。利用数值模拟得到的VIC振幅，评估了在有电离层探空仪的地区散射e云的时间演变。有证据表明，从HWM模式和风切变理论的框架中得到的中性风型可以解释散散e - e的年演变、空间范围和季节波动。此外，研究了2014年1月和7月射电掩星数据中散射e的全球分布。分析了夏季半球散散e的不同季节依赖性。

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引用次数: 0

Numerical differentiation approaches for kinematic orbit solutions 运动轨道解的数值微分方法

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.11.059

P.R. Zapevalin , V.E. Zharov

This paper investigates numerical differentiation methods for obtaining velocities and accelerations from kinematic low-Earth orbits using simulated data and data from the GOCE and GRACE-FO missions with reduced-dynamic orbits as a reference. Kinematic orbits are crucial for independent gravity field modeling in the long-wavelength part of the spectrum free from a priori gravity assumptions, but they lack direct velocity and acceleration data, requiring numerical differentiation of the orbit data. We compare central difference approximation, Extended Differentiation and Savitzky-Golay filtering, chosen based on previous literature, and integrate low-pass filters (FIR, IIR) to reduce noise amplification. Power spectral density analysis and error metrics for GOCE and GRACE-FO show that despite slight differences in these missions, SGF and low-pass filtering generally yield the best accuracy in determining kinematic velocity. These studies can be used to construct new gravity field maps and can also be considered for future geodetic applications.

本文以模拟数据和GOCE和GRACE-FO任务的减动力轨道数据为参考，研究了获取运动近地轨道速度和加速度的数值微分方法。运动学轨道对于独立的重力场建模是至关重要的，在光谱的长波长部分，没有先验的重力假设，但它们缺乏直接的速度和加速度数据，需要对轨道数据进行数值微分。我们比较了中心差分近似、扩展微分和Savitzky-Golay滤波，并结合低通滤波器（FIR， IIR）来降低噪声放大。GOCE和GRACE-FO的功率谱密度分析和误差指标表明，尽管这些任务略有不同，SGF和低通滤波通常在确定运动速度方面产生最好的精度。这些研究可用于构建新的重力场图，也可用于未来的大地测量应用。

引用次数: 0

Dynamics of submicrometric dust grains in Mercury’s exosphere 水星外逸层亚微米尘埃颗粒的动力学

IF 2.8 3区地球科学 Q2 ASTRONOMY & ASTROPHYSICS

Advances in Space Research

Pub Date : 2026-02-01 DOI: 10.1016/j.asr.2025.12.057

Alberto Flandes , Harald Krüger

<div><div>The exosphere of Mercury is a collisionless-low-density layer of gravitationally bound atoms and molecules that extends from the surface up to several planetary radii. Most of these molecules follow ballistic trajectories after being released through different mechanisms like vaporisation from the hypervelocity impacts of micrometeoroids (with impacts speeds <span><math><mrow><mo>></mo><mn>80</mn><mspace></mspace><mtext>km</mtext><mo>/</mo><mtext>s</mtext></mrow></math></span>) mainly of cometary origin that also excavate considerable amounts of dust from which a dust exosphere is built. In the case of the Moon’s dust cloud, the exospheric dust population observed by Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment Explorer (LADEE) comprise grains with radii <span><math><mrow><mi>≳</mi><mn>0.3</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span>. It is expected that the impact dust grains of the clouds of Mercury and the Moon have similar sizes, however, given that Mercury is subject to much more intense weathering processes compared to the Moon a somewhat smaller ejecta dust grain population may be present at Mercury.</div><div>The aim of this work is to study the dynamics of the impact ejecta grains of the exosphere of Mercury inside its Hill sphere, where the exosphere is confined. We focus on the submicrometric population and consider, not only grains with radii <span><math><mrow><mo>∼</mo><mn>0.1</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> (as those observed at the Moon), but we will explore the possibility of grains as small as <span><math><mrow><mn>10</mn><mspace></mspace><mi>nm</mi></mrow></math></span>, considering that the smallest (submicrometric) ejecta grains, are able to achieve the largest speeds. Although we are able to estimate some properties of the exosphere, one question that we try to answer is whether instruments like the Mercury Dust Monitor (MDM) on board the Mercury Magnetospheric Orbiter, also known as Mio, would be able to detect some of the grains of the hermean dust exosphere once in orbit around Mercury. Mio, from the Japan Aerospace Exploration Agency (JAXA) is part of the BepiColombo mission, which among its many objectives will study the hermean exosphere after November 2026. In particular, MDM is a piezoelectric (PZT) dust impact instrument that will be dedicated to study the distribution of interplanetary dust at the orbit of Mercury. Our estimations indicate that, it is likely, that MDM would be able to detect ejecta dust particles with radii as small as <span><math><mrow><mn>50</mn><mspace></mspace><mi>nm</mi></mrow></math></span> as long as they have a relative speed of <span><math><mrow><mo>></mo><mn>5</mn><mspace></mspace><mtext>km</mtext><mo>/</mo><mtext>s</mtext></mrow></math></span> with respect to the detector. On the other hand, it should be able to detect ejecta particles with radii <span><math><mrow><mi>≳</mi><mn>

水星的外逸层是一个没有碰撞的低密度层，由引力束缚的原子和分子组成，从表面延伸到几个行星半径。这些分子中的大多数在通过不同的机制被释放后遵循弹道轨迹，比如由微流星体（撞击速度为80公里/秒）的超高速撞击蒸发，这些微流星体主要来自彗星，也会挖掘出相当数量的尘埃，从而形成尘埃外逸层。在月球尘埃云的情况下，月球大气与尘埃环境探测器（LADEE）上的月球尘埃实验（LDEX）观测到的外逸层尘埃包括半径为0.3μm的颗粒。预计水星和月球云的撞击尘埃颗粒大小相似，然而，考虑到水星受到比月球更强烈的风化过程的影响，水星上的喷射尘埃颗粒数量可能会稍微小一些。这项工作的目的是研究水星外逸层在希尔球（Hill sphere）内部的撞击喷射颗粒的动力学，希尔球是外逸层的限制所在。我们专注于亚微米粒子群，不仅考虑半径为~ 0.1μm的粒子（如在月球上观察到的），而且考虑到最小的（亚微米）喷射粒子能够达到最大的速度，我们将探索小至10nm的粒子的可能性。虽然我们能够估计外逸层的一些特性，但我们试图回答的一个问题是，一旦进入水星轨道，像水星磁层轨道飞行器（也称为Mio）上的水星尘埃监测器（MDM）这样的仪器是否能够探测到水星外逸层的一些尘埃颗粒。来自日本宇宙航空研究开发机构（JAXA）的Mio是BepiColombo任务的一部分，该任务的众多目标之一是在2026年11月之后研究月球外逸层。特别是，MDM是一种压电（PZT）尘埃撞击仪器，将专门用于研究水星轨道上的行星际尘埃分布。我们的估计表明，只要相对于探测器的相对速度为5km/s， MDM就有可能探测到半径小至50nm的喷射尘埃颗粒。另一方面，它应该能够检测半径大于或等于100nmas的喷射粒子，只要它们的撞击速度大于或等于1km/s。

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