http://scholars.ntou.edu.tw/handle/123456789/196 2026-04-08T16:02:31Z http://scholars.ntou.edu.tw/handle/123456789/26505 標題: Assessing CO₂ sources and sinks in and around Taiwan: Implication for achieving regional carbon neutrality by 2050( vol 206 , 116664, 2024) 作者: Hung, Chin-Chang; Hsieh, Hsueh-Han; Chou, Wen-Chen; Liu, En-Chi; Chow, Chun Hoe; Chang, Yi; Lee, Tse-Min; Santsch, Peter Hans; Ranatunga, R. R. M. K. P.; Bacosa, Hernando P.; Shih, Yung-Yen 2025-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26459 標題: Holocene environmental evolution of the Pinqing Lagoon: insights from multiproxy sediment analysis 作者: Tang, Zih-Wei; Wang, Liang-Chi; Chen, Huei-Fen; Rahman, Abdur; Chou, Yu-Min; Li, Hong-Chun 摘要: To address the environmental changes in the South China coastal region and to investigate the interplay among sea-level fluctuations, monsoon variability, and sediment dynamics, a sediment core from the Pinqing Lagoon was extracted, covering the last 8.5 ka. Furthermore, multiple proxies were analyzed in the core, including grain size end-members (EM1, EM2, and EM3), magnetic susceptibility and S-ratio, the carbon (C) isotopic composition of organic matter, its carbon and nitrogen (N) contents, the resulting C/N ratio, and Itrax XRF-derived elemental ratios such as Mn/Ti, Si/Ti, K/Ti, and Fe/Ti. The results reveal that changes in sea level play a primary role in shaping the lagoon sedimentary and geochemical evolution, with EASM-driven runoff acting as a secondary control on terrestrial sediment supply, especially during low sea-level phases. During the 8.5-6.8 ka, low water levels, strong EASM-driven runoff, and dominant terrestrial C-4 plant input resulted in coarse detrital sedimentation (high EM2 and low S-ratio) and poor bottom water oxygenation (low Mn/Ti). Between 6.8 and 5.8 ka, despite already high sea levels, the lagoon underwent rapid deepening, with a shift toward in-situ aquatic productivity, improved oxygenation, and finer sedimentation (EM1 dominance and high S-ratio), likely reflecting local geomorphological changes. From 5.8 to 4.2 ka, as sea level stabilized, the lagoon became stratified and marine-influenced, with low oxygenation, minimal terrestrial input, and background fine-grained sedimentation. After 4.2 ka, stable high water levels and low runoff persisted. A prominent EM3 peak between 0.4 and 0.2 ka, coinciding with the Late Little Ice Age (LIA), reflects frequent typhoon-induced high-energy deposition, supported by coarse grain size, elevated MS, and increased Si/Ti, K/Ti, and Fe/Ti ratios. Overall, the results highlight that long-term sea-level fluctuations primarily controlled lagoonal sedimentation and oxygenation, while EASM variability shaped runoff-driven detrital input. 2025-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26452 標題: Student's t Kernel-Based Maximum Correntropy Criterion Extended Kalman Filter for GPS Navigation 作者: Jwo, Dah-Jing; Chang, Yi; Hsu, Yun-Han; Biswal, Amita 摘要: Global Navigation Satellite System (GNSS) receivers may produce measurement outliers in real-world applications owing to various circumstances, including poor signal quality, multipath effects, data loss, satellite signal loss, or electromagnetic interference. This can lead to a noise distribution that is non-Gaussian heavy-tailed, affecting the effectiveness of satellite navigation filters. This paper presents a robust Extended Kalman Filter (EKF) based on the Maximum Correntropy Criterion with a Student's t kernel (STMCCEKF) for GPS navigation under non-Gaussian noise. Unlike traditional EKF and Gaussian-kernel MCCEKF, the proposed method enhances robustness by leveraging the heavy-tailed Student's t kernel, which effectively suppresses outliers and dynamic observation noise. A fixed-point iterative algorithm is used for state update, and a new posterior error covariance expression is derived. The simulation results demonstrate that STMCCEKF outperforms conventional filters in positioning accuracy and robustness, particularly in environments with impulsive noise and multipath interference. The Student's t-distribution kernel efficiently mitigates heavy-tailed non-Gaussian noise, while it adaptively adjusts process and measurement noise covariances, leading to improved estimation performance. A detailed explanation of several key concepts along with practical examples are discussed to aid in understanding and applying the Global Positioning System (GPS) navigation filter. By integrating cutting-edge reinforcement learning with robust statistical approaches, this work advances adaptive signal processing and estimation, offering a significant contribution to the field. 2025-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26420 標題: Enhanced deoxygenation and carbon storage in the mid-depth subarctic Pacific during the Bølling-Allerød 作者: Li, Qian; Li, Qingping; Chen, Min-Te; Zhou, Shouwei; Zou, Jianjun; Shi, Xuefa 摘要: Reconstructing changes in ocean carbon reservoir is essential for understanding how oceans regulate atmospheric carbon dioxide (CO2) fluctuations. It has been considered that large amounts of CO2 were released from the deep subarctic Pacific during the B & oslash;lling-Aller & oslash;d (BA). However, this is inconsistent with the slowing or pausing of atmospheric CO2 rise throughout the BA. On this issue, an increase of carbon storage in the mid-depth subarctic Pacific is speculated, more geological reconstructions are needed to confirm it. Here, we present magnetofossils and redox-sensitive trace elements records from core LV63-41-2 retrieved from the mid-depth western subarctic Pacific to reconstruct the paleo-redox conditions and carbon storage changes spanning the last deglaciation. The significantly increased proportion of elongated magnetofossils and the enrichment of authigenic U are identified during the BA, consistently indicating lower oxygen concentration in the overlying bottom water and sediment pore water. This BA deoxygenation was widespread across mid-depth subarctic Pacific areas and could reflect increased respired dissolved inorganic carbon storage. Furthermore, the lowoxygen sedimentary environment would facilitate more organic carbon to be buried in sediments. The increases in respired carbon storage and organic carbon burial in the mid-depth subarctic Pacific might have slowed BA atmospheric CO2 rise. This study highlights the significant application value of magnetofossils in reconstructing paleo-redox conditions in the subarctic Pacific and points out the important role of the mid-depth subarctic Pacific in regulating atmospheric CO2 fluctuations. 2025-01-01T00:00:00Z