hq»·ÇòÌåÓý

2025Äê1ÔÂ

Paleoclimate data assimilation: Principles and prospects¹ÅÆøºòÊý¾Ýͬ»¯£ºÔ­ÀíºÍÕ¹Íû

Zhang, Haoxun; Li, Mingsong ; Hu, Yongyun

Abstract

Reconstructing climate states during geological periods is a key focus in studying Earth system evolution. Substantial progress has been achieved in reconstructing paleoclimate and paleoenvironment using both Earth system models and paleoclimate proxies. However, current paleoclimate reconstructions face several challenges: the accuracy of Earth system model simulations relies on model parameter settings. Paleoclimate proxy data exhibit significant variability across different periods and regions, and proxy data are often sparse, hindering the accuracy and global relevance of proxy-based reconstructions. Addressing the pros and cons of these methods, paleoclimate data assimilation can effectively integrate Earth system models and paleoclimate proxy data, enhancing the precision and global relevance of reconstructions. Using approaches such as the ensemble Kalman filter as an example, this paper introduces the principles of paleoclimate data assimilation and reviews recent advancements in reconstructing paleoclimate states using these techniques. Paleoclimate data assimilation offers new insights and advanced techniques for paleoclimate reconstruction, with potential applications extending to the entire Cenozoic, Mesozoic, and even Paleozoic eras. These applications could deepen our understanding of the past climatic backgrounds of extreme climate events such as glacial-interglacial cycles, hyperthermals, and oceanic anoxic events, providing a reference for predicting future climate change.

Source

SCIENCE CHINA-EARTH SCIENCES

Volume68Issue2Page407-424

DOI10.1007/s11430-024-1439-y

2025Äê2ÔÂ

Characterization and risk assessment of microplastics in shoreline sediments of the Yellow River Delta

Islam, Tariqul ; Cheng, Hefa

Abstract

As the intersection of river, sea, and land, river deltas are hotspots for the accumulation of microplastics (MPs). This study investigated the abundance and characteristics of MPs in surface sediments from shoreline area of the Yellow River Delta in northern China, elucidated their sources, and assessed their risk. The MPs isolated from sediment samples were detected and characterized using optical microscopy and micro-Fourier transform infrared spectroscopy (mu-FTIR). The results showed that MPs were abundant (360-2160 items/kg) in the area, and occurred mainly in small sizes (<250 mu m), as fibers (20.2-50.0%), filament (4.8-21.5%), and granules (8.5-20.6%), and in transparent (27.8-40.3%), blue (11.2-31.6%), or black (7.9-26.5%) color. Polyethylene terephthalate (26.08%), polyethylene (20.47%), polypropylene (13.49%), and polyvinyl chloride (10.71%) were the dominant polymer types for the MPs. The pollution load indices (1-6) indicated that all sampling sites were polluted by MPs, while the polymeric hazard indices (65.14-91.44) suggested that MPs pollution of the area was in medium range. Overall, the ecological risk indices (91.44-475.38) of the sampling sites indicated that MPs in shoreline sediments of the Yellow River Delta posed low to considerable potential ecological risk. While the dominance of polymers with medium polymeric risk scores rendered the MPs in the shoreline sediments with relatively low risk, the majority of MPs occurred in small sizes, which complicates the actual risk posed by MPs in shoreline sediments of the Yellow River Delta and deserves attention.

Source

MARINE ENVIRONMENTAL RESEARCH

Volume204

DOI10.1016/j.marenvres.2024.106933

2025Äê2ÔÂ

Flow characteristics of gas and liquid in pipeline revealed by machine learning on distributed acoustic sensing data      

Ku, Haochu ; Zhang, Kun-peng; He, Xiang-ge ; Zhang, Min ; Lu, Hai-long ; Zhang, Yi; Cong, Lin

Abstract

The two-phase flow rates of gas and liquid in a pipeline are crucial parameters for optimizing gas-oil production strategies and ensuring the reliability of gas-oil transportation systems. Although available measurement techniques, such as various flow meters, offer accurate flow rate data, they might face limitations in providing distributed and real-time information at multiple points. Distributed Acoustic Sensing (DAS) offers a viable alternative for long-term, multipoint dynamic monitoring of the flow. However, the data acquired through fiber optic monitoring techniques are often difficult to analyze and process in real-time, while machine learning offers automatic identification of complex patterns and relationships within the data, enabling more precise predictions and classifications. To evaluate the feasibility of DAS technology combined with machine learning methods to estimate the gas-liquid flow rate in pipelines, an experimental loop that utilized DAS was developed to measure gas-liquid two-phase flow signals in pipelines. The machine learning method was then applied to analyze the DAS signals, based on which models were established to predict flow rates and regimes. Furthermore, validation experiments were conducted to assess the predictive performance of these models. Compared to the actual flow rates measured by electronic flowmeters, the results by integration of DAS and machine learning show the predictive accuracy of two models reach 97%. In the subsequent validation experiments, both the goodness of fit for the flow rate prediction model and accuracy for the flow regime prediction model exceeded 85%. Thus, compared to current flow measurement methods, the integration of DAS and machine learning not only provides accurate flow rate estimations but also offers available prediction of flow regimes, enhancing the measurement capabilities and technology insights.

Source

GEOENERGY SCIENCE AND ENGINEERING

Volume245

DOI10.1016/j.geoen.2024.213518

2025Äê3ÔÂ

Origin and evolution of the North Atlantic Oscillation    

Song, Zhihong ; Nie, Ji ; Dai, Panxi; Lin, Zhongxi ; Guo, Jiaqi ; Lan, Jiawenjing; Li, Xiang; Lin, Qifan ; Yin, Zihan; Yang, Jun ; Liu, Yonggang ; Yang, Haijun ; Hu, Yongyun

Abstract

The North Atlantic Oscillation (NAO), the dominant mode of atmospheric variability in the North Atlantic region, plays a crucial role in weather and climate. Here, to investigate when the NAO emerged and how it evolved over geological timescales, we analyzed time-slice paleoclimate simulations during the breakup of the supercontinent Pangea, starting 160 million years ago (Ma). Our findings indicate that a present-day-like NAO mode gradually formed between 80 Ma and 60 Ma, driven by the expansion of the North Atlantic Ocean and the enhanced land-ocean contrast. This expansion led to a regime transition in Northern Hemisphere winter circulation, characterized by a westward shift of the North Atlantic jet, a strengthening of the North Atlantic high pressure and storm track, and the emergence of NAO-like variability. The confluence of orographic effects of the Rocky Mountains also contributed to the strengthening of the NAO. This study depicts the evolutionary history of the NAO over geological time and reveals its coherent relationship with the evolution of continents and orography.

Source

NATURE COMMUNICATIONS

Volume16Issue1

DOI10.1038/s41467-025-57395-4

2025Äê3ÔÂ

Accelerated northward shift of the North Pacific transition zone chlorophyll front under greenhouse warming

Chen, Yihui ; Wu, Sheng; Zhang, Jian ; Cui, Qi

Abstract

The transition zone chlorophyll front (TZCF) has significant implications for marine ecosystems, fisheries and ocean carbon cycling in the North Pacific. Recent satellite observations show TZCF shifting notably northward at a rate of 1.40 degrees per decade from 1998 to 2022, accompanied by a reduction of the chlorophyll concentration in the TZ. Using CMIP6 models with longer data, we find that this northward shift of TZCF is robust and accelerates with increasing warming. The weakening of zonal wind stress under global warming leads to a shallower vertical mixed layer and reduces southward transport via horizontal Ekman. These changes result in decreased nutrients in the upper ocean, ultimately causing a reduction in phytoplankton biomass in the North Pacific TZ and a northward shift of the TZCF. Our findings reveal a significant intervention of anthropogenic warming on marine ecosystems and provides a framework for understanding the linkage between anthropogenic warming and phytoplankton dynamics in the open ocean.

Source

ENVIRONMENTAL RESEARCH LETTERS

Volume20Issue4

DOI10.1088/1748-9326/adbfa7

2025Äê3ÔÂ

Decoding Fluid Flow Characteristics Through Distributed Acoustic Sensing: A Novel Approach  

Ku, Haochu ; Zhang, Kunpeng; He, Xiangge ; Zhang, Min ; Lu, Hailong

Abstract

Flow characteristic monitoring includes parameters such as flow regime, fluid characteristic frequency, and flow rate, which are crucial for optimizing production and ensuring the safety of oil and gas transportation systems. Existing fluid monitoring technologies, such as various flow meters, often face limitations in providing distributed and real-time monitoring data. In contrast, distributed acoustic sensing offers a spatial resolution of 1 m with high frequency sampling capability, allowing for long-term, multi-point dynamic monitoring of fluid migration characteristics. We developed an indoor physical simulation pipeline loop to assess the feasibility of using distributed acoustic sensing for monitoring flow migration characteristics. The experiment collected signal characteristics under different conditions, including background noise, single gas-phase flow, single liquid-phase flow, and gas-liquid two-phase flow. In the frequency-power spectral density analysis, single gas-phase flow signals are concentrated at lower frequencies, single liquid-phase flow displays noticeable spikes over a broader frequency range, and gas-liquid two-phase flow covers the widest frequency range with stronger amplitude signals. Autocorrelation analysis shows larger oscillations for gas-liquid two-phase flow, smoother signals for gas-phase flow, and more turbulent signals for liquid-phase flow. By examining root mean square energy changes, flow rates can be qualitatively estimated, revealing a positive correlation between energy and flow velocity. Finally, the study discussed the limitations of the experimental setup and proposed improvements and advanced research directions of distributed acoustic sensing in fluid monitoring.

Source

SENSORS

Volume25Issue7

DOI10.3390/s25072011

2025Äê4ÔÂ

Bomb-produced radiocarbon dynamics and salinity-water isotopes relationship at two stations in the tropical South Pacific Ocean and implications for upper ocean processes

Liang, Yongqi; Zhou, Liping; An, Yongrui;  Gao, Pan;  Shi, Xuefa;  Huang, Mu;  Liu, Kexin

Abstract

We report results of radiocarbon (C-14) of dissolved inorganic carbon together with oxygen and hydrogen isotope compositions (delta O-18 and delta D) in water samples collected from two stations along the World Ocean Circulation Experiment Hydrographic Program transect P17 in the South Pacific in March and April 2018. We quantify the changes of bomb-produced radiocarbon (bomb-C-14) in the seawater and compare them with data previously reported for the stations around. The penetration depth of the bomb-C-14 at both stations remains above 500 m over the period of 1991-2018, pointing to limited vertical mixing due to the isopycnal circulation in the upper ocean. The estimated inventory in the entire water column at two stations has decreased to an averaged value of 8 x 10(9) atoms cm(-2) over the 27 years. The maximum reduction in Delta C-14 values occurs at similar to 200 m in the upper part of the thermocline and is attributed to the migration of the subtropical water northward to the tropics. A relatively shallow slope in the relationship between salinity and water isotopes is also observed in the seawater samples of 100-300 m depth from the two stations, which is interpreted as resulting from the sinking of the subtropical surface seawater after strong evaporation. Such isotope properties constrained by the combined C-14, delta O-18 and delta D data characterize the water that feeds the Equatorial Undercurrent.

Source

JOURNAL OF OCEANOGRAPHY

Volume81Issue2Page101-112

DOI10.1007/s10872-024-00740-w

2025Äê4ÔÂ

An interpretable approach to estimate the self-motion in fish-like robots using mode decomposition analysis  

Zhai, Yufan;  Zheng, Xingwen;  Chao, Li-Ming;  Li, Shikun;  Xiong, Minglei;  Jia, Yongxia;  Li, Liang;  Xie, Guangming

Abstract

The artificial lateral line system, composed of velocity and pressure sensors, is the sensing system for fish-like robots by mimicking the lateral line system of aquatic organisms. However, accurately estimating the self-motion of the fish-like robot remains challenging due to the complex flow field generated by its movement. In this study, we employ the mode decomposition method to estimate the motion states based on artificial lateral lines for the fish-like robot. We find that primary decomposed modes are strongly correlated with the velocity components and can be interpreted through Lighthill's theoretical pressure model. Moreover, our decomposition analysis indicates the redundancy of the sensor array design, which is verified by further synthetic analysis and explained by flow visualization. Finally, we demonstrate the generalizability of our method by accurately estimating the self-states of the fish-like robot under varying oscillation parameters, analyzing three-dimensional pressure data from the computational fluid dynamics simulations of boxfish (Ostracion cubicus) and eel-like (Anguilla anguilla) models, and robustly estimating the self-velocity in complex flows with vortices caused by a neighboring robot. Our interpretable and generalizable data-driven pipeline could be beneficial in generating hydrodynamic sensing hypotheses in biofluids and enhancing artificial-lateral-line-based perception in autonomous underwater robotics.

Source

NATURE COMMUNICATIONS

Volume16Issue1

DOI10.1038/s41467-025-58880-6

2025Äê4ÔÂ

A Review of Research on Pursuit-evasion Games ×·ÌÓ²©ÞÄÎÊÌâÑо¿×ÛÊö

Song-Yu CHI , Shuai LI, Chen WANG, Guang-Ming XIE

Abstract

As an important branch of multi-agent adversarial games, pursuit-evasion (PE) games have found widespread applications in the fields of control and robotics, attracting considerable attention from researchers. PE games primarily focus on the dynamic games between pursuer and evader, each striving to achieve their respective objectives: The pursuer aims to capture the evader as quickly as possible, while the evader£§s goal is to avoid capture. This article provides an overview of the research progress in PE games, and introduces various settings of PE games across five key dimensions, including spatial environment, information acquisition, and so on. It briefly describes four mainstream methods for solving PE games, including theoretical approaches, numerical approaches, and so on. By summarizing and analyzing existing researches, this article offers several research suggestions, which are expected to provide significant guidance for future developments in PE games.

Source

Acta Automatica Sinica,  

2025, 51(4): 705?726

doi:  10.16383/j.aas.c240396

2025Äê4ÔÂ

PV-PASBLS: A Multimodal Point-View Fusion Model Based on Parameter Adaptive Stacked Broad Learning System for 3-D Shape Recognition

Zhiyuan Liao; Chunquan Li; Hui Jin; Beike Li; Zhijun Zhang; Junzhi Yu

Abstract

Most existing multimodal point-view fusion models for 3-D shape recognition typically improve recognition accuracy through complex feature fusion mechanisms. However, these mechanisms significantly increase the model¡¯s complexity and computational cost. To address this issue, a novel multimodal point-view fusion model based on a parameter adaptive stacked broad learning system (PV-PASBLS) for 3-D shape recognition is proposed. This model avoids complex feature fusion mechanisms, thereby reducing computational cost and increasing flexibility. Specifically, PV-PASBLS employs a backbone network for point cloud and multiview feature extraction to effectively capture the relevant features. Simple concatenation is then used for feature fusion. Importantly, PV-PASBLS is adaptive, allowing the backbone network to be replaced or adjusted to meet specific task requirements. Since PV-PASBLS avoids complex fusion mechanisms, the responsibility for achieving high-accuracy recognition is shifted to its classification network. To achieve this, a novel classification network, named the parameter adaptive stacked broad learning system (PASBLS), is proposed. PASBLS utilizes a new interval adaptive hyperparameter optimization (IAHPO) algorithm based on MARS. By constructing a surrogate model for a stacked broad learning system (SBLS) in PASBLS, IAHPO can quickly and efficiently identify the optimal hyperparameters, ensuring that PV-PASBLS maintains high recognition accuracy and mitigates potential accuracy losses due to the absence of complex fusion mechanisms. To validate the effectiveness of PV-PASBLS, comprehensive experiments were conducted on the public 3-D shape datasets ModelNet40 and ScanObjectNN, comparing it with state-of-the-art methods. Experimental results demonstrate that PV-PASBLS outperforms its competitors, achieving higher accuracy and improved training efficiency. In addition, the IAHPO algorithm was evaluated on the NORB classification dataset and ten UCI regression datasets, showing that it can achieve better hyperparameters with a lower computational cost.

Source

IEEE Transactions on Instrumentation and Measurement, vol. 74, pp. 1-14, 2025, Art no. 5025414, doi: 10.1109/TIM.2025.3551981

2025Äê5ÔÂ

Occurrence and Risk Assessment of Microplastics Pollution in the World's Longest Natural Beach, Cox's Bazar, Bangladesh  

Islam, Tariqul;  Cheng, Hefa

Abstract

Microplastics (MPs) are omnipresent in all ecosystems, and sediments are considered as their ultimate sink in marine environment. This study focused on the occurrence, characteristics, and risk of MPs in the beach sediments of Cox's Bazar, Bangladesh. Sediment samples were collected from a total of 17 sites from four study areas hosting various types of aquacultural, agricultural, animal agricultural, and tourism activities during the peak tourist season. Stereomicroscopy, micro-Fourier transform infrared spectroscopy (mu-FTIR), and scanning electron microscopy (SEM) were used for qualitative and quantitative characterization of MPs. MPs were detected in all beach sediment samples, with abundance ranging from 280 to 1060 items/kg. Overall, small sizes (< 250 mu m), fibrous and granular shapes, white and transparent color were the major characteristics for MPs in the beach sediments. The dominant polymer types for the MPs were PP (24.89%), LDPE (21.85%), and HDPE (18.06%). The risk of MPs in the beach sediments was quantitatively assessed with the pollution load index (PLI, 1.0-3.78), polymeric hazard index (PHI, 49.5-70.0), and ecological risk index (ERI, 54.3-232). MPs in the sediments of Kolatoli sea beach had the highest average PLI (2.32), which is indicative of significant pollution, while those in the sediments of Darianagar beach point had the lowest average PLI (1.07). The average PHI values of MPs in the four study areas (57.2 to 63.4) were within the medium range, while the average ERI values (61.1 to 135) were indicative of low to medium ecological risk. While the ecological risk of MPs in the beach sediments of Cox's Bazar is relatively low due to the dominance of polymers with low risk scores, efforts devoted to the management of plastic waste should be made to prevent further accumulation of MPs.

Source

WATER AIR AND SOIL POLLUTION

Volume236Issue5

DOI10.1007/s11270-025-07978-0

2025Äê5ÔÂ

Extreme Indian summer monsoon states stifled Bay of Bengal productivity across the last deglaciation  

K. Thirumalai, S. C. Clemens, Y. Rosenthal, S. Conde, K. Bu, S. Desprat, M. Erb, L. Vetter, M. Franks, J. Cheng, L. Li, Z. Liu, L. P. Zhou, L. Giosan, A. Singh & V. Mishra

Abstract

Indian summer monsoon (ISM) hydrology fuels biogeochemical cycling across South Asia and the Indian Ocean, exerting a first-order control on food security in Earth's most densely populated areas. Although the ISM is projected to intensify under continued greenhouse forcing, substantial uncertainty surrounds anticipating its impacts on future Indian Ocean stratification and primary production-processes key to the health of already-declining fisheries in the region. Here we present century-scale records of ISM runoff variability and marine biogeochemical impacts in the Bay of Bengal (BoB) since the Last Glacial Maximum (similar to 21 thousand years ago (ka)). These records reveal extreme monsoon states relative to modern strength, with weakest ISM intensity during Heinrich Stadial 1 (similar to 17.5-15.5 ka) and strongest during the early Holocene (similar to 10.5-9.5 ka). Counterintuitively, we find that BoB productivity collapsed during both extreme states of peak monsoon excess and deficits-both due to upper-ocean stratification. Our findings point to the possibility of future declines in BoB primary productivity under a strengthening and more variable ISM regime.

Source

NATURE GEOSCIENCE

Volume18Issue5Page443-449

DOI10.1038/s41561-025-01684-6

2025Äê6ÔÂ

Remote effect of tropical South Atlantic variability on the Pacific-Japan pattern

Wenwen Yang, Xichen Li, Lin Wang, Yurong Hou, Yonghao Wang, Yujie Miao & Weihan Ma      

Abstract

The Pacific-Japan (PJ) pattern is a significant teleconnection influencing the East Asian summer climate across multiple timescales. Previous studies indicated that the tropical Pacific and Indian Ocean variability may largely contribute to the PJ variability, while the influence from the tropical Atlantic is relatively less understood. This study suggests that the tropical South Atlantic (TSA) sea surface temperature (SST) can drive the PJ pattern in boreal summer via analysis of observational and reanalysis datasets and numerical experiments. Multiple atmospheric dynamical processes and atmosphere-ocean interactions contribute to this teleconnection. The TSA warming excites a Kelvin wave pattern that propagates eastward to the tropical Indo-Western Pacific. The meridional gradient of Kelvin wave-induced easterly anomalies over the Western North Pacific (WNP) generates anticyclonic anomalies, further amplified by barotropic energy conversion, triggering a PJ-like circulation anomaly. Additionally, the easterly wind anomaly may heat the SST over the Maritime Continent through the wind-evaporation-SST effect, further enhancing the PJ pattern through diabatic heating. This finding builds a teleconnection from the tropical Atlantic to the East Asia summer climate and offers insights for additional predicational potentials for the East Asian summer monsoon. It might help to improve climate prediction and future projection in East Asia and have broad implications for agriculture, energy supply, and public health in this region.

Source

CLIMATE DYNAMICS

Volume63Issue6

DOI10.1007/s00382-025-07718-4

2025Äê6ÔÂ

Computational Analysis of Radiative Williamson Hybrid Nanofluid Comprising Variable Thermal Conductivity (vol 60, 087004, 2021)    

Zubair, Tamour; Usman, Muhammad; Hamid, Muhammad; Sohail, Muhammad; Nazir, Umar; Nisar, Kottakkaran Sooppy; Vijayakumar, Velusamy

Abstract
This article demonstrates the study of thermal energy with the rheology of Williamson liquid over a rotating surface. The correlations between nanoparticles and hybrid nanoparticles in the base fluid are considered to determine the comparative analysis in nanoparticles and hybrid nanostructures. The variable terms are thermal conductivity and thermal radiation, which are also inserted in the energy equation with the associations of nano and hybrid nanoparticles. The ordinary differential equations (ODEs) are generated from the modeled problem using transformation. In contrast, the least square method is used to simulate analytic solutions of required ODEs, and further results are compared with a numerical scheme. The simulations of temperature and motion of fluid particles are performed in graphs and tables. The reduction in motion of fluid particles is captured versus the variation of Williamson number and magnetic number. At the same time, Williamson's number and magnetic parameter also reduce momentum boundary layer thickness. The hybrid nanoparticles play a vital impact on producing a high rate of acceleration in flow, and hybrid nanoparticles are useful to produce maximum energy compared to nanostructures.

Source

JAPANESE JOURNAL OF APPLIED PHYSICS

Volume64Issue6

DOI10.35848/1347-4065/add1a3

2025Äê6ÔÂ

Tropical Indian Ocean warming drives an increase in bering sea ice concentration

Yonghao Wang, Xi Liang, Haibo Bi, Yurong Hou & Xichen Li

Abstract

Arctic sea ice has undergone rapid changes in recent decades and exhibited significant interannual variability. Factors such as changes in greenhouse gas concentrations, sea ice-albedo feedback, and cloud feedback are known to influence Arctic sea ice variability. Both the Pacific and the Atlantic oceans have been reported to impact Arctic sea ice through atmospheric and oceanic processes. However, limited research has focused on the influence of the Indian Ocean on Arctic sea ice, partly due to the considerable distance between the Indian and Arctic Ocean basins. This study investigates the influence of tropical Indian Ocean warming on the Arctic sea ice concentration (SIC). Through statistical analysis and numerical experiments, we demonstrate that tropical Indian Ocean warming can increase Bering Sea SIC in boreal winter (December-January-February, DJF). The warming excites a Rossby wave train that propagates into the high-latitude Pacific Ocean, resulting in an anomalous low-pressure center over the Bering Strait. The associated cyclonic circulation induces a pronounced southwestward drift of sea ice from the Bering Sea to the high-latitude North Pacific, extending from the Bering Strait to about 60 degrees N over the North Pacific, contributing to the increase in Bering Sea SIC. This result establishes a robust linkage between the Indian Ocean and the Arctic, which may largely influence the predictability and the future projection of Arctic climate. Moreover, given that Arctic sea ice may provide feedback to the Indian monsoon system, these two areas thus form an interactive system that requires further investigation.

Source

CLIMATE DYNAMICS

Volume63Issue6

DOI10.1007/s00382-025-07723-7

2025Äê6ÔÂ

Unveiling ongoing biogeochemical dynamics of CDOM from surface to deep ocean    

Shansheng Mo, Zhongli Liu, Yuanhao Hao, Norbert Hertkorn, Hanzhe Wang, Chenyang Zhang, Gregory Korshin, Jinren Ni & Mingquan Yan

Abstract

Understanding the dynamics of marine dissolved organic carbon (DOC) is essential for predicting its role in carbon cycling and its response to climate change. Here, we unveil molecular transformations of marine chromophoric dissolved organic matter (CDOM) across the global ocean using Ultraviolet-visible spectroscopy. Significant variability in CDOM composition within the epi- and mesopelagic layers (?<?1000?m) correlates with physicochemical parameters, driven by irradiation, primary production, biological activity, transport, and riverine inputs. In the bathypelagic layer (1000¨C5000?m), up to 18.2% of highly conjugated molecules transform into low-molecular-weight CDOM, despite stable DOC concentrations. This dynamic process sustains biomass production and respiration in deep ocean, contributing a carbon flux of 3¨C24 Pg C yr?1¡ªup to an order of magnitude more than the fast-sinking particulate organic carbon flux. Our findings offer insights into the molecular transformation of deep-ocean DOM and underscore the need to reassess the bathypelagic DOC pool¡¯s role in the global carbon cycle.

Source

NATURE COMMUNICATIONS

Volume16Issue1

DOI10.1038/s41467-025-60510-0

2025Äê6ÔÂ

Keystone taxa mediate the trade-off between microbial community stability and performance in activated sludges

Xiaonan Liu, Miaoxiao Wang, Bingwen Liu, Xiaoli Chen, Liyun An, Yong Nie & Xiao-Lei Wu

Abstract

Microbial communities form complex interaction networks where species cooperation is crucial for maintaining stability and performance. However, the key species and their specific roles in maintaining these properties remain poorly understood. Here, to address this, we conducted a large-scale network analysis of microbial communities in 1,186 activated sludge samples worldwide. The resulting activated sludge co-occurrence network exhibited a typical scale-free structure, with most taxa having few connections and a select few being highly interconnected. A group of keystone taxa, distinguished by high connectivity and a critical role in network stability, was identified. Microbial communities harbouring keystone taxa were more stable but exhibited lower pollutant removal rates. Comparative analysis showed that, in response to industrial wastewater inflow, communities with keystone taxa maintained more stable composition and species abundance while achieving similar pollutant removal rates. These results demonstrate that, while keystone taxa are critical for microbial community stability, this stability comes at the cost of reduced function in activated sludge systems. This study provides deeper insights into the link between community composition, stability and function, highlighting the potential to optimize microbial performance by manipulating keystone taxa.

Source

NATURE WATER

Volume3Issue6

DOI10.1038/s44221-025-00451-6

2025Äê7ÔÂ

Impact of Indian Ocean sea surface temperature anomalies on winter wheat yields in China

Hui Ren, Xiufen Li, Pengkun Liu, Yi Zhou, Tianyi Zhang & Xichen Li

Abstract

Wheat is one of the most important crops globally. It also plays a pivotal role in ensuring food security in China. The production of wheat is highly sensitive to regional weather conditions, which could be further influenced by sea surface temperature (SST) variabilities all over the globe through atmospheric teleconnections. This research employed statistical methods to evaluate the impact of Indian Ocean sea surface temperature (SST) anomalies on winter wheat yield and compared it with the influence of the El Ni & ntilde;o-Southern Oscillation (ENSO). The results indicate that from January to March of the same year, the positive phase of the Indian Ocean Basin mode (IOBM) is typically associated with a decline in winter wheat yields in the southern North China Plain and the middle and lower reaches of the Yangtze River. Conversely, during the spring season, the positive phase of the Southern Indian Ocean Dipole (SIOD) is significantly correlated with an increase in winter wheat yields in these regions. Further analysis reveals that Indian Ocean SST variabilities primarily affect winter wheat yields by regulating precipitation and solar radiation. Moreover, we find that the significant impacts of IOBM and SIOD on winter wheat may surpass those of ENSO. These findings highlight the critical role of SST variabilities in determining winter wheat yields, elucidating its underlying mechanisms, and providing valuable scientific evidence to support food security efforts for policymakers and farmers.

Source

THEORETICAL AND APPLIED CLIMATOLOGY

Volume156Issue8

DOI10.1007/s00704-025-05602-z

2025Äê8ÔÂ

Impacts of tropical sea surface temperature variability on oil palm yield in Malaysia    

Duan Zhang, Jing Wang, Yi Zhou, Miao Cui and Xichen Li?

Abstract

As the world's second-largest palm oil producer, Malaysia plays a vital role in global supply chains. Understanding the impact of tropical Indian and Atlantic Ocean Sea Surface Temperature (SST) variability on palm yield is crucial for ensuring stable production and pricing. This study statistically assesses the influence of three tropical ocean variability indices on Malaysia's national palm yield, after removing the influence of the Ni & ntilde;o 3.4 index. Results indicate that the Indian Ocean Basin (IOB) and Tropical North Atlantic (TNA) indices during April-May-June (AMJ) are negatively correlated with yields from September to December, while a positive Indian Ocean Dipole (IOD) anomaly in JJA is linked to 1.45% yield anomalies increase, particularly in July and August. Additionally, higher temperatures during the flowering stage before harvest usually reduce yield, while changes in precipitation patterns have different effects on yields in East Malaysia and Peninsular Malaysia. Our results also provide quantitative evidence on how tropical ocean variability impacts palm oil production in Malaysia, especially in the critical September-December period. This research provides valuable information for improving yield predictions and managing climate-related risks, contributing to the stability of both Malaysia's palm oil production and the global palm oil market.

Source

ENVIRONMENTAL RESEARCH COMMUNICATIONS

Volume7Issue8

DOI10.1088/2515-7620/adf79a

2025Äê8ÔÂ

Monolithic Programmable Fabric-Stacking Enables Multifunctional Soft Robots    

Jiaxi Wu; Mingxin Wu; Chen Wang; Guangming Xie

Abstract

Inspired by natural organisms, soft robots have showcased remarkable performance across various functions. However, creating multifunctional soft robotic systems typically increases manufacturing complexity, resulting in a cumbersome fabrication workflow with low programmability. Here, we present a monolithic fabric-based approach for the programmable fabrication of multifunctional soft robots. Our method involves programming bonding paths and sequentially attaching fabric layers to directly manufacture monolithic robots. The fabric is precisely shaped using a laser cutter, while a 3-D printer follows predesigned bonding paths to ensure repeatable manufacturing. By programming the contours of each fabric layer and their corresponding bonding paths, we create versatile soft robots that integrate expected functionalities, including large-range manipulation, multimodal locomotion, and their harmonious combination. Our approach offers a promising avenue to efficiently create multifunctional soft robots via monolithic and customized fabrication, which will accelerate the proliferation of soft robots and open the doors to a wide range of applications.

Source

IEEE TRANSACTIONS ON ROBOTICS

Volume41Page4810-4828

DOI10.1109/TRO.2025.3593118

2025Äê8ÔÂ

Bioinspired underwater soft robots: from biology to robotics and back      

Lei Li, Boyang Qin, Wenzhuo Gao, Yanyu Li, Yiyuan Zhang, Bo Wang, Shihan Kong, Jian Wang, Dekui He, Junzhi Yu

Abstract

The ocean vast unexplored regions and diverse soft-bodied marine organisms have spurred interest in bio-inspired underwater soft robotics. Recent advances have enabled new capabilities in underwater movement, sensing, and interaction. However, these efforts are largely unidirectional, with biology guiding robotics while insights from robotics rarely feed back into biology. Here we propose a holistic, bidirectional framework that integrates biological principles, robotic implementation, and biological validation. We show that soft robots can serve as experimental tools to probe biological functions and even test evolutionary hypotheses. Their inherent compliance also allows them to outperform rigid systems in unstructured environments, supporting applications in marine exploration, manipulation, and medicine. Looking forward, we introduce bio-universal-inspired robotics, a paradigm that transcends species-specific mimicry by identifying convergent principles across species to inspire more adaptable designs. Despite rapid progress, challenges persist in material robustness, actuation efficiency, autonomy, and intelligence. By uniting biology and engineering, soft robots can advance ocean exploration and deepen scientific discovery.

Source

arXiv:2508.11883 [cs.RO]

     (or arXiv:2508.11883v1 [cs.RO] for this version)

https://doi.org/10.48550/arXiv.2508.11883

2025Äê8ÔÂ

Optimizing microalgae cultivation for enhanced lutein production: screening of high-yield strains and cultivation strategy development

Yuelian Li, Han Sun, Yunlei Fu, Shufang Yang & Xue Lu

Abstract

Microalgae are widely recognized as a promising source of lutein. However, the potential of lutein production by different microalgae varies greatly. This study aims to optimize lutein production by screening high-yield microalgae strains and refining cultivation conditions. Four microalgae strains-Selenastraceae sp. B10, Pectinodesmus sp. F13, Parachlorella kessleri HH2, and Chlorella protothecoides CS-41-were evaluated under autotrophic, heterotrophic, and mixotrophic cultivations. The result indicated that biomass concentration and lutein content were higher in P. kessleri HH2 and C. protothecoides CS-41. The modified Basal medium facilitated the specific growth rate of 1.99 day-1 of P. kessleri HH2, and the maximum biomass concentration of 33.3 g L-1 was achieved by fed-batch cultivation, which was four times higher than batch cultivation. Under autotrophic cultivation, P. kessleri HH2 exhibited robust growth with a maximum biomass of 12.05 g L-1 in high-light and narrow-diameter tubes, while the maximum lutein yield of C. protothecoides CS-41 was 27.77% higher than that of P. kessleri HH2. Two-staged cultivation further improved lutein yield of C. protothecoides CS-41 by 179% increase than that of heterotrophic group. Furthermore, compared to red light and blue light, white light was indicated to increase both cell growth and lutein synthesis of C. protothecoides CS-41, with the biomass concentration of 21.20 g L-1, lutein content of 7.67 mg g-1 and lutein yield of 138.15 mg L-1, which were 5.21%, 16.31% and 42.00% higher than those obtained under blue light, respectively. Consequently, this study indicated that C. protothecoides CS-41 was a promising source for lutein production.

Source

JOURNAL OF APPLIED PHYCOLOGY

Volume37Issue4Page2281-2293

DOI10.1007/s10811-025-03578-x

2025Äê8ÔÂ

Climate impacts of the El Ni?o-Southern Oscillation in Africa    

Wenju Cai, Chris Reason, Elsa Mohino, Belen Rodr¨ªguez-Fonseca, Johan Malherbe, Agus Santoso, Xichen Li, Hector Chikoore, Hyacinth Nnamchi, Michael J. McPhaden, Noel Keenlyside, Andrea S. Taschetto, Lixin Wu, Benjamin Ng, Yi Liu, Tao Geng, Kai Yang, Guojian Wang, Fan Jia, Xiaopei Lin, Shujun Li, Yun Yang, Junkai Wang, Li Zhang, Ziguang Li, Pokam Wilfried, Liming Zhou, Xuebin Zhang, Francois Engelbrecht, Zhuoran Li & Joseph N. Mutemi

Abstract

The El Ni & ntilde;o-Southern Oscillation (ENSO) - describing shifts between warm El Ni & ntilde;o and cold La Ni & ntilde;a phases - has a substantial effect on the global climate. In this Review, we outline the mechanisms and climate impacts of ENSO in Africa, focusing on rainfall. ENSO's influence varies strongly by season, region, phase, event and decade, highlighting complex dynamics and asymmetries. Although difficult to generalize, key characteristics include: anomalies across the Sahel in July-September, related to the tropospheric temperature mechanism; a strong dipole in anomalies between eastern and southern Africa during October-December (the short rain reason) and December-February, linked to interactions with the Indian Ocean Dipole and Indian Ocean Basin mode, respectively; and anomalies over southern Africa (with possible indications of opposite anomalies over East Africa) during March-May (the long rain season), associated with continuation of the Indian Ocean Basin mode. These teleconnections tend to be most pronounced for East Pacific El Ni & ntilde;o and Central Pacific La Ni & ntilde;a events, as well as during decades when interbasin interactions are strongest. Although challenging to simulate, climate models suggest that these impacts will strengthen in the future, manifesting as an increased frequency of ENSO-related dry and wet extremes. Given the reliance of much of Africa on rain-fed agriculture, resolving these relationships is vital, necessitating realistic simulation of regional circulations, ENSO and its interbasin interactions.

Source

NATURE REVIEWS EARTH & ENVIRONMENT

Volume6Issue8Page503-520

DOI10.1038/s43017-025-00705-7

2025Äê9ÔÂ

Warming triggers polar carbon-mercury decoupling: Climate perturbation and biogeochemical disruption

Chengzhen Zhou, Maodian Liu, Xuejun Wang

Abstract

Warming-driven melting of glaciers and sea ice increases mercury (Hg) inputs to the Southern Ocean, where it can be methylated and enter food webs. Concurrently, faster carbon recycling in these waters accelerates local heating, further exacerbating Hg remobilization. This concern demands governance innovation that recognizes the cryosphere as a biogeochemical threat vector, both a source of greenhouse gases and a sink for atmospheric pollutants. Urgent interdisciplinary action must bridge contaminant control and climate mitigation to avert irreversible tipping points in Earth's climate frontiers.

Source

ECO-ENVIRONMENT & HEALTH

Volume4Issue3

DOI10.1016/j.eehl.2025.100175

2025Äê9ÔÂ

Collapse of the Atlantic Meridional Ocean Circulation Induced by Precession: Sensitivity to Orbital Acceleration    

Haobo Liu, Yonggang Liu, Lorraine Lisiecki, Yu Gao, Ming Zhang, Qifan Lin

Abstract

While orbital forcing-induced weakening of the Atlantic meridional overturning circulation (AMOC) potentially facilitated glacial initiation during the Quaternary glacial-interglacial cycles, this mechanism has remained to be confirmed by atmosphere-ocean general circulation models (AOGCMs). Our simulations with an AOGCM demonstrate that without any freshwater hosing, a complete AMOC collapse can be achieved through precessional forcing alone under high eccentricity and relatively low atmospheric CO2 level (pCO2). Crucially, the multi-millennial timescale required for full AMOC response to precessional forcing suggests that the orbital acceleration techniques in AOGCM simulations, often adopted to save computation time, likely obscured detection of these abrupt AMOC transitions in previous studies.

Source

GEOPHYSICAL RESEARCH LETTERS

Volume52Issue18

DOI10.1029/2025GL115941

2025Äê9ÔÂ

Response of Oceanic Meridional Overturning Circulation to Vegetation Removal on Different Continents

Jiaqi Guo, Yonggang Liu, Shuai Yuan, Xiang Li, Yue Liu, Yongyun Hu

Abstract

Vegetation on different continents is often subject to substantial changes due to climate change, anthropogenic activities, or vegetation evolution, but how it affects the oceanic meridional overturning circulation (MOC) is unclear. This study explores both the transient evolution and equilibrium response of MOCs to vegetation removal on each continent except Antarctica using an atmosphere-ocean general circulation model, CESM1.2.2, under preindustrial climate conditions. The results indicate that at equilibrium, removing Eurasian vegetation slightly weakens the Atlantic MOC (AMOC) (-2.5 Sv, -16.5%) but enhances the Pacific MOC (PMOC) (+6.0 Sv, +58.3%). Conversely, removing North American vegetation strengthens the AMOC (+2.7 Sv, +17.6%) while weakening the PMOC (-1.8 Sv, -17.7%). Vegetation removal over low-latitude regions produces minimal impact on either AMOC or PMOC. Global vegetation removal causes a substantial weakening of AMOC (-5.7 Sv, -36.9%) and a pronounced strengthening of PMOC (+4.8 Sv, +47.3%), different from the linear sum of individual effects described above. The transient evolution of both AMOC and PMOC is complex, exhibiting distinct (even opposite) responses in the multidecadal timescale and centennial or millennial timescale. Abrupt changes in both AMOC (by similar to 10 Sv) and PMOC (by similar to 2 Sv) occur around 2700 years after the global vegetation removal. This highlights the long timescale of surface-climate responses to external forcings, which is easily overlooked in shorter simulations. Process diagnostics show that salinity anomalies-modulated by net precipitation and sea ice melt-govern the AMOC response, whereas surface temperature anomalies dominate the PMOC response.

Source

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS

Volume130Issue9

DOI10.1029/2025JC022978

2025Äê9ÔÂ

Fish trawling and climate perturbations threaten the largest marine mercury sink  

Maodian Liu, Chengzhen Zhou, Qianru Zhang, Peter A. Raymond, Xiaolong Li, Robert P. Mason, Taylor Maavara, Junjie Wang, Hehao Qin, Guofeng Shen, Dongqiang Zhu, Xuejun Wang & Thomas S. Bianchi

Abstract

Global seafood demand is increasing while oceans continue to receive substantial anthropogenic mercury, heightening concerns about the toxic methylmercury bioaccumulation in seafood. Presently, the fate of mercury in the ocean remains uncertain, hindering comprehensive assessments of marine mercury dynamics and seafood safety. Here we leverage an observation-driven dataset to demonstrate that approximately  of mercury is buried annually in continental shelves, substantially reducing its bioaccumulation potential in marine food webs. This flux is sixfold greater than that in the United Nations Environment Programme¡¯s last report and twofold to sevenfold that of deep-sea sediment burial, making continental shelves the largest marine mercury sinks. Since industrialization, mercury levels in surface shelf sediments have tripled, indicating that most buried mercury is of anthropogenic origin. However, this sink is increasingly threatened by climate-related processes, bottom trawling and dredging, which physically remobilize mercury through diffusion, stirring, redistribution and off-shelf transport. Empirical extrapolations suggest that ongoing trawling, dredging and warming may transform coastal sediments from mercury sinks to net sources. This shift may have already occurred in parts of Europe¡¯s shelves, though additional verification is required. Our findings highlight the urgent need to reduce anthropogenic mercury and greenhouse gas emissions and balance fishery demand with ecosystem conservation to sustain these critical mercury sinks.

Source

NATURE SUSTAINABILITY

Volume8Issue11

DOI10.1038/s41893-025-01642-5

2025Äê10ÔÂ

Lagged response of the inorganic carbon system at eastern edge of the West Pacific Warm Pool to the ENSO events      

Xi Lu, Liping Zhou

Abstract

As a vast and highly variable natural source of atmospheric carbon dioxide (CO2), the equatorial Pacific holds a pivotal position in the global carbon cycle. Here we examine the inorganic carbon system and related parameters in the west subtropical-equatorial Pacific surface seawater during a research cruise from February to April 2023. We find that the distributions of dissolved inorganic carbon (DIC), CO2 partial pressure (pCO(2)), and their anomalies in the study area display typical "La Nina featured" patterns, despite the neutral phase of El Nino-Southern Oscillation (ENSO) then. Analyses on the interannual variations of February-to-April mean CO2 fugacity (fCO(2)) anomalies in the eastern West Pacific Warm Pool (WPWP) relative to the 3-month running mean of Nino3.4 index revealed a similar to 5-month lag between the ENSO events and the strongest response of fCO(2) at eastern edge of the WPWP. This lag can be attributed to the combined effect of climate system development, thermal and chemical equilibrium, and physical mixing. Our work highlights the need for sustaining observations of marine carbon system, especially in climate-sensitive areas.

Source

GLOBAL AND PLANETARY CHANGE

Volume253

DOI10.1016/j.gloplacha.2025.104910

2025Äê10ÔÂ

Regional Perspective of Hadley Circulation and Its Uncertainties among Different Datasets: Biases of ENSO-Related Hadley Circulation in CMIP Models  

Wenzhu Wang, Juan Feng, Yadi Li, Yujie Miao & Xichen Li

Abstract

The Hadley Circulation (HC), a fundamental component of global atmospheric circulation, plays an important role in the global energy balance and transport of moisture. The interaction between ENSO and the HC significantly impacts tropical climate and has broad implications for global climate variability through atmospheric teleconnections. The HC is usually represented by the mass stream function. As a result, it can rarely be observed through in-situ measurement. Reanalysis datasets and CMIP models are frequently used to investigate the properties of the HC. Previous studies systematically assess the capability of these CMIP models to represent the spatial distribution and intensity of the HC anomalies associated with ENSO events. However, most of these studies investigate the HC anomaly from a global perspective. In this work, we focus on evaluating the ability of CMIP6 models to capture the three-dimensional features of ENSO-related HC anomalies in comparison to that in six reanalysis datasets. Results show a consistent westward shift of the ENSO-related HC over the tropical Central-Eastern Pacific in almost all CMIP6 models, accompanied by a weakening of the asymmetric component of the ENSO-related HC over the equatorial Pacific. The former is mainly attributed to the westward extension of the Pacific cold tongue in CMIP models, while the latter is more related to the southward shift of the ENSO-related SST and precipitation anomalies in CMIP models. One should be aware of these biases when studying the ENSO-related atmospheric circulation changes. Our study has broad implications for ENSO simulations and the predictability of ENSO-related global climate variabilities.

Source

ADVANCES IN ATMOSPHERIC SCIENCES

Volume42Issue10Page2067-2082Special IssueSI

DOI10.1007/s00376-025-4459-9

2025Äê10ÔÂ

Beyond propulsion: muscle proprioception enables hydrodynamic sensing in fish body      

Rahdar Hussain Afridi , Waqar Hussain Afridi , Muhammad Hamza , Mingxin Wu , Li-Ming Chao , Yufan Zhai , Liang Li, Guangming Xie

Abstract

In aquatic environments, muscle activity in free-swimming fishes not only propels body undulations to generate thrust but also serves as proprioceptive sensors for detecting surrounding fluid dynamics. Testing the proprioceptive function of the muscle is challenging owing to its deep integration with swimming activity. To address this, we introduce an experimental platform that records up to 12-channel electromyography (EMG) signals synchronized with detailed kinematics in koi and carp. We first apply various neural networks to map densely collected EMG signals to synchronized video-based body kinematics, thereby validating our EMG collection system. We then compare EMG data from fishes swimming in various laminar flows and within K & aacute;rm & aacute;n vortices. Our results show that the phase of muscle activity consistently precedes body kinematics in various laminar flows. While within K & aacute;rm & aacute;n vortices, we observe a mixed phase relationship, where muscle activity sometimes leads and at other times lags behind body kinematics. This suggests that fishes may use muscle proprioceptive sensing when interacting with complex flows, such as nearby vortices. Our research not only introduces novel methods for biological EMG studies but also offers insights that could influence the design of bio-inspired underwater sensory systems.

Source

PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES

Volume292Issue2057

DOI10.1098/rspb.2025.0474

2025Äê10ÔÂ

Transient modeling for ocean redox conditions during the mid-cretaceous Oceanic Anoxic Event 2  

Qi Cui, Jian Zhang, Yongyun Hu, Sascha Fl?gel, Huifang Guo, Yihui Chen

Abstract

Reconstructions of the mid-Cretaceous Oceanic Anoxic Event 2 (OAE2) indicate that the ocean redox state was temporally and spatially heterogeneous. Its evolution is considered to be induced by the variation of atmospheric carbon dioxide concentrations (pCO(2)) due to the activities of large igneous provinces (LIPs) and associated changes in global meridional overturning circulation, nutrient input, and phosphorus recycling. However, their respective roles on the OAE2 are still under debate. Here, we conduct transient numerical simulations using an intermediate-complexity Earth system model with reconstructed pCO(2) values. In our simulations, bottom anoxia occurred in the equatorial Atlantic Ocean and the Tethyan rim before OAE2. This changed only slightly with varying pCO(2). In contrast, increasing nutrient concentrations due to increased continental weathering can lead to a marked increase in anoxic areas, which is further expanded by enhanced phosphorus recycling in the lowoxygen marine area. The North Atlantic, low-latitude South Atlantic, Southeast Pacific, and Western Tethys oceans are most prone to developing bottom water anoxia. The modeled anoxic areas exhibit distinctly different spatio-temporal patterns during OAE2 with varying weathering intensities. Comparison of the simulation results with newly assembled geological records suggests that anoxic bottom water only accounted for similar to 20-40% of the global bottom area and that the continental phosphorus weathering intensity was increased by similar to 40-60% compared to the pre-OAE2 level.

Source

GLOBAL AND PLANETARY CHANGE

Volume253

DOI10.1016/j.gloplacha.2025.104976

2025Äê10ÔÂ

Relative Effect of Indian Ocean in the Indo-Pacific/North America Teleconnection

Hou, Yurong; Johnson, Nathaniel C.; Yoo, Changhyun; Wang, Ya; Sun, Weijun; Man, Kai; Li, Xichen

Abstract

The impact of the Indian Ocean on North America has long been considered a passive and secondary effect of the El Ni & ntilde;o-Southern Oscillation (ENSO)-induced Pacific-North American (PNA) teleconnection, largely because of the strong covariability between the Pacific and Indian Ocean, as well as the small interannual variance of Indian Ocean sea surface temperatures (SSTs). However, the relative importance of the Indian Ocean-induced teleconnection has not been well quantified. In this study, with a combination of observation-based statistical analysis and atmospheric model simulations, we single out the Indian Ocean-North American (INA) teleconnection pattern, represented as a Rossby wave train pattern from the subtropical Indian Ocean to North America along the westerly jet. While the PNA pattern drives a north-south contrast temperature pattern over North America in boreal winter, the Indian Ocean warming in turn induces an eastern warming-western cooling pattern. Further analysis indicates that both the atmospheric circulation and surface temperature anomalies associated with the PNA and INA patterns are additive. More importantly, about half of the Indian Ocean SST variability is independent of ENSO, which also contributes substantially to the wintertime North American climate. During ENSO events, an anomalously warm or cold Indian Ocean may drive distinct climate anomalies over the east and west coasts of the United States. Our study highlights the relative importance of the Indian Ocean in driving the tropical ocean-midlatitude teleconnection patterns, which has broad implications for the predictability and future projection of wintertime North American climate.

Source

JOURNAL OF CLIMATE

Volume38Issue20Page5577-5593

DOI10.1175/JCLI-D-24-0676.1

2025Äê10ÔÂ

Stability of the marine nitrogen cycle over the past 165 million years  

Linda V. Godfrey, Anne Willem Omta, Eli Tziperman, Xiang Li, Yongyun Hu & Paul G. Falkowski

Abstract

Nitrogen and phosphorus are the two macro-nutrients that limit biological productivity in the ocean. While the supply of P depends on geological processes, N is biologically supplied from an inexhaustible atmospheric source, but can be limited by micro-nutrients, especially iron. Here we present a record of N and C isotopes over the past 165 Ma in marine sediments to address feedbacks between the N-cycle and productivity. Over most of the last 165 Myr, the fixed N averaged +3.2 parts per thousand, (-2 and +9 parts per thousand), but higher in distal areas of the ocean due to limited vertical mixing. Using an isotope box model and a coupled climate model we show that this is caused by winds that induce upwelling changing due to continental meander. Upwelling along low latitude east-west orientated Tethyan coastlines results in low delta 15N, while upwelling along narrow N-S coastlines as it does today, results in high delta 15N due to denitrification.

Source

NATURE COMMUNICATIONS

Volume16Issue1

DOI10.1038/s41467-025-63604-x

2025Äê10ÔÂ

Ekman Theory with Damping    

Jiacheng Wu, Yonggang Liu, Rui Xin Huang, Jinhan Xie, Zhaoying Wang, Shaoqing Zhang

Abstract

The observed Ekman spirals in the ocean are always "flatter" than that predicted by the classic theory. We propose that the universal flattening of Ekman spiral is mainly due to the damping associated with turbulent dissipation. Analytical solutions and numerical simulations show convincingly a better fitting between the new theory and observations. Most importantly, the new theory indicates that the damping can lead to weakened Ekman transport and pumping, with the latter not only driven by the curl but also the divergence of wind stress. Under a modest damping, the Ekman transport along 26.5¡ãN will be ~0.4 Sv (12%) smaller than that predicted by the classic theory. Hence, the damping due to turbulent dissipation can noticeably affect the wind-driven circulation in the upper ocean.

Source

arXiv:2505.02068 [physics.ao-ph]

     (or arXiv:2505.02068v1 [physics.ao-ph] for this version)

https://doi.org/10.48550/arXiv.2505.02068

2025Äê11ÔÂ

Binary-Tree Structure for Extended Range-Distributed Acoustic Sensing

Xiangge He, Zhi Cao, Min Zhang, Hailong Lu

Abstract

The dual-pulse heterodyne demodulation distributed acoustic sensing (HD-DAS) system has superior performance but is fundamentally limited by the short sensing range, which poses a significant obstacle to its application in long-distance monitoring. This paper proposes and experimentally demonstrates a novel binary-tree structure DAS (BTS-DAS) aimed at overcoming this critical limitation. By physically decoupling the long-distance transmission fiber from the final sensing part, this structure effectively expands the system's remote sensing capability without compromising the high pulse repetition rate for high-performance measurement. We identified modulation instability (MI), rather than stimulated Brillouin scattering (SBS), as the dominant nonlinear noise source in the extended fiber chain. Through careful power management, we established an optimal launch power window. The practical feasibility of the system was verified during on-site testing, where vibrations were successfully detected over a 10 km transmission link with sensing occurring in the 250 m sensing fiber segment, achieving a low background noise of -59.79 dB ref rad/Hz. This work presents a robust and scalable solution for long-range, high-performance acoustic sensing.

Source

APPLIED SCIENCES-BASEL

Volume15Issue21

DOI10.3390/app152111748

2025Äê11ÔÂ

Intermittent swimming demonstrates energy-saving capabilities: experimental evidence from robotic fish

Ruosi Liu, Qiye Yang, Yang Ding, Guangming Xie

Abstract

Intermittent swimming, characterized by the combination of active propulsion and passive gliding, is a typical locomotion pattern in most aquatic creatures. While its potential for energy conservation has been widely hypothesized, the lack of direct quantitative evidence has led to ongoing debate and limited its practical implementation in underwater robotics. In this study, we first investigated the intermittent swimming behavior of koi carp under varying flow velocities. Our findings reveal that, rather than adjusting oscillation frequency or amplitude, koi carp primarily modify the coasting periods between consecutive oscillations to optimize their response to different hydrodynamic conditions. To directly understand this strategy through the view of swimming efficiency, we developed a biomimetic fish-like robot inspired by koi carp, which enabled precise measurement of energy consumption across a range of cyclic and intermittent swimming patterns. Experimental results show that fishlike intermittent swimming significantly reduces energy expenditure compared to cyclic swimming, with longer coasting periods correlating with greater energy savings. This provides direct evidence that energy savings primarily stem from the introduction of intermittency. Our study not only offers a novel quantitative framework for investigating intermittent swimming behaviors but also demonstrates the potential of bio-inspired strategies for advancing energy-efficient underwater robotics.

Source

OCEAN ENGINEERING

Volume340Part2

DOI10.1016/j.oceaneng.2025.122335

2025Äê11ÔÂ

Tropical Pacific Zonal Temperature Gradient Intensified by the Tibetan Plateau Surface Darkening  

Tang, Shuchang; Piao, Shilong ; Cai, Wenju; Wang, Tao ; Li, Laurent Z. X.; Wang, Kai ; Kan, Fei ; Gui, Yanchen; Yao, Tandong; Li, Xichen

Abstract

The Tibetan Plateau (TP) is experiencing substantial changes in land properties, particularly a decrease in albedo, known as "TP surface darkening." These changes have profound impacts on global climate, but whether and how TP darkening influence Pacific climate variability is unknown. Here, using an Earth System Model, we find TP darkening contributes to North Pacific Meridional Mode-like cooling anomaly over the subtropical Pacific particularly in boreal winter and spring. This anomaly induces persistent annual near-surface easterly winds in equatorial Pacific and strengthens Walker Circulation in a series of atmosphere-ocean interactions, culminating in an intensified tropical Pacific zonal temperature gradient especially during boreal summer and autumn. Our finding underscores TP darkening might be taken into account in the debate of tropical Pacific El Ni & ntilde;o-like warming pattern under greenhouse warming, and demonstrates that the tropical Pacific could serve as intermediaries for TP-driven changes to influence global climate.

Source

GEOPHYSICAL RESEARCH LETTERS

Volume52Issue21

DOI10.1029/2025GL117253

2025Äê11ÔÂ

Researches and applications of high-performance quasi-distributed and distributed optical fiber vibration sensors for oil and gas industry      

Liu, Fei ; Zhou, Tong ; Huang, Xin ; Zhang, Min ; Zhu, Guo ; Zhao, Hanyu ; Tan, Guozhen ; Zhou, Xian

Abstract

Oil and gas industry is a significant application area for optical fiber sensors, among which the quasi-distributed and distributed optical fiber vibration sensors play promising roles in the sectors of exploration, exploitation, production, and transportation within the oil and gas industry. These scenarios put forward stringent requirements for the performance metrics of optical fiber vibration sensors, including noise floor, dynamic range, and real-time performance to ensure practical usage, particularly in harsh environments. Here we briefly introduce the related works in our research group about the quasi-distributed and distributed optical fiber vibration sensors, specially focusing on the optimizations of the sensors' measurement resolution, enhancements of dynamic range, improvements of stability and developments of post-processing algorithms. The developed quasi-distributed and distributed optical fiber vibration sensors have been successfully applied in several oil field applications, such as microseismic monitoring and hydraulic fracturing. Finally, we summarize our research efforts and anticipate future development directions for optical fiber vibration sensors in the oil and gas industry.

Source

Proceedings of the SPIE, Volume 13654, id. 136541C 13 pp. (2025).

DOI: 10.1117/12.3058337

2025Äê11ÔÂ

Ë®ÏÂÈíÌåץȡÊÖÑо¿ÏÖ×´¼°Ó¦ÓÃÕ¹Íû

ÂÀâù㣬ºúò«ÕÜ£¬ÍõÔóÓÔøÐÂÅ࣬ÎäÃ÷ÐÅ£¬Íõ³¿£¬Ð»¹ãÃ÷

Abstract

With the increasing demand for marine resource development and environmental protection,underwater robots have an urgent need for flexible,safe,and efficient soft grasping technology.This paper described three main actuation design methods for underwater soft grippers:fluid variable pressure drive,cable drive,and smart material drive.Based on this,the research progress of key technologies such as bio-inspired design,stiffness adjustment technology,integration of grasping and perception,and multi-modal grasping was analyzed.Combined with typical application scenarios such as marine waste cleanup,aquatic product fishing,underwater archaeology,and cultural relic protection,as well as biological sample collection,the unique advantages of soft grippers in non-destructive sampling,adaptability to multiple types of objects,and fine operations in the deep sea were analyzed.Finally,the future research directions of underwater soft grippers were prospected,and it is pointed out that efforts should be focused on the research and development of high-performance underwater intelligent materials,the integration of multiple driving methods,and the optimization of energy and control systems,so as to promote the evolution of the gripper towards deep sea and intelligentization and achieve reliable underwater operations in all scenarios.

Source

Journal of Unmanned Undersea Systems, 2025, 33(5): 769-779.

doi: 10.11993/j.issn.2096-3920.2025-0107

2025Äê11ÔÂ

Atlantic-Pacific Multidecadal Variability Modulates the North Atlantic Oscillation-North Atlantic Tripole Relationship      

Shu Gui, Zizhen Dong, Ruowen Yang, Lei Cai, Xichen Li, Haojie Wu, Yali Yang, Yu Lian

Abstract

The North Atlantic Oscillation (NAO)-North Atlantic Tripole (NAT) relationship has revealed distinct fluctuation on the decadal time scale, with its mechanism remaining unclear. We in this study suggest the NAO-NAT relationship is combinedly modulated by the Atlantic Multidecadal Variability (AMV)-Pacific Decadal Oscillation (PDO), and the latent heat flux (LHF) plays a key role during the process. The cyclonic anomaly over the subtropical North Atlantic as the consequence of positive AMV and negative PDO enhances the LHF on the decadal time scale, which promotes consistent covariation in the atmospheric baroclinicity and the eddy-mean flow interaction. It leads to positive feedback manifesting the NAO-NAT relationship. Conversely, the negative AMV and positive PDO can symmetrically weaken the NAO-NAT relationship. The above mechanism is verified by model experiment. This study offers new insights on the air-sea interaction modes between Pacific and Atlantic Oceans, as well as their trans-scale multi-basin linkages.

Source

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES

Volume130Issue22

DOI10.1029/2025JD044924

2025Äê12ÔÂ

The enigmatic Norian-Rhaetian boundary: Varying carbon cycle disturbances in continental and deep marine records

Xia Hua, David B. Kemp, Tenichi Cho, Masayuki Ikeda, Chunju Huang

Abstract

The Norian-Rhaetian transition (late Sevatian through early Rhaetian) was associated with a series of faunal turnovers and a putative global carbon cycle perturbation, as evidenced by one or more negative carbon isotope excursions (NCIEs) that occur in locations around the world. Deciphering the pattern, timing and causes of these NCIEs is crucial for understanding the characteristics and causal mechanisms of environmental change across the Norian-Rhaetian boundary (NRB). Currently, however, there is no agreed position and definition of the NRB. Moreover, records of the Sevatian-early Rhaetian from terrestrial and deep marine sites are largely uninvestigated. Here we present organic carbon isotope (delta C-13(org)) and associated geochemical data across upper Norian to lower Rhaetian strata from a non-marine section at St Audrie's Bay, UK (west European lacustrine basin) and a pelagic deep-marine section at Katsuyama, Japan (central Panthalassa Ocean). Both sites show putative NCIEs, but they were likely of different ages. At St. Audrie's Bay, a cluster of NCIEs (maximum magnitude of -3.5 parts per thousand) likely span between similar to 207.6 Ma and similar to 206.6 Ma based on paleomagnetically-calibrated astronomical time constraints, whereas smaller magnitude NCIEs (maximum magnitude of -2 parts per thousand) at Katsuyama were likely older (similar to 210 Ma). Our new data underline the probable multi-phased nature of Sevatian-early Rhaetian carbon cycle changes, and also help to demonstrate that differences in NCIE magnitudes in different locations were at least in part linked to varying relative amounts of terrestrial and marine organic matter. Hg enrichment within the NCIE interval at Katsuyama supports the emerging view that volcanism was a driver of carbon cycle disturbance near the base of the Rhaetian.

Source

GLOBAL AND PLANETARY CHANGE

Volume255

DOI10.1016/j.gloplacha.2025.105084

2025Äê12ÔÂ

Bio-to-Robot Transfer of Fish Sensorimotor Dynamics via Interpretable Model

Waqar Hussain Afridi; Ahsan Tanveer; Rahdar Hussain Afridi; Muhammad Hamza

Abstract

Swimming in fish arises from tightly integrated neural, muscular, skeletal, and hydrodynamic processes that are difficult to capture in compact, transferable models for robotics. An interpretable system identification (SySID) is presented that bidirectionally maps between electromyography (EMG) and kinematics in freely swimming koi and further tests its generalization to a robotic fish. Synchronized EMG and kinematic are collected across laminar, K¨¢rm¨¢n vortex, and reverse K¨¢rm¨¢n vortex flows spanning 0.146¨C0.274 m s??. A linear autoregressive with exogenous input (ARX) model architecture is chosen to capture both feedforward (EMG to kinematics) and feedback (kinematics to EMG) pathways, enabling the extraction of key system parameters, such as natural frequency, damping ratio, and input¨Coutput delays. Cross©\individual validation demonstrates robust performance and identifies the best©\performing fish©\trained model, which is then evaluated for cross©\domain transfer by replacing EMG input with processed pulse width modulation actuation signals from a robotic fish. Despite differences in mechanics and actuation physics, predictions closely match measured trajectories (mean R? = 0.86 ¡À 0.13), substantially outperforming a deep neural network (97.8% higher percentage fit index) trained on the same biological datasets. These findings show that compact, interpretable SySID models enable accurate bio©\to©\robot transfer without robot©\specific retraining, grounding robotic motion models directly in biological function rather than imitation.

Source

Advanced Intelligent Systems

DOI:10.1002/aisy.202501117

2025Äê12ÔÂ

Ocean Circulation on Tide-locked Lava Worlds: 3D Modeling with a Simple Boundary Iteration Method  

Jun Yang, Chengyao Tang, Zimu Wang, Yanhong Lai, Wanying Kang

Abstract

Tide-locked lava worlds are surface-melted rocky planets under 1:1 tidally locked orbit (i.e., synchronously rotating) with orbital period being equal to rotation period and with permanent hot dayside and cold nightside. Previous studies on this type of planets employed scaling analyses and two-dimensional (2D) simulations. This work is a continuation of the previous researches but including the effect of the Coriolis force and the simulation domain is extended to a 3D global sphere. We find that under the condition with thermal-only forcing (without surface wind stresses), the area-mean ocean depth is about 50--300 m (depending on vertical diffusivity) and the area-mean effect of horizontal ocean heat transport (in the order of 10 to 10 W m) is significantly smaller than stellar radiation (in the order of 10 W m at the substellar region), being consistent with previous results. Different from 2D results, due to the effect of the Coriolis force, large-scale horizontal gyres form on the dayside, ocean currents near the west boundaries are much stronger than that near the east boundaries (called as ``western intensification''), the deepest ocean is not right at the substellar point but in the middle latitudes as the vertical diffusivity is moderate or large, and meanwhile there exists significant asymmetry between the west and the east of the substellar point. These results establish a first picture for the 3D thermal-driven ocean circulation and confirm that the lava ocean should be shallow on tide-locked lava worlds.

Source

ASTROPHYSICAL JOURNAL LETTERS

Volume995Issue1

DOI10.3847/2041-8213/ae1cc0

2025Äê12ÔÂ

The preseason warming of the Indian Ocean resulting in soybean failure in US    

Menghan Li, Xichen Li, Yi Zhou, and Yurong Hou

Abstract

Soybean is the most important oilseed and feed crop globally. As one of the major soybean producers in the world, soybean yield variability in the United States has garnered widespread attention. We analyze the effect of the Indian Ocean sea surface temperature (SST) on soybean yield variability. Our findings indicate that variations in Indian Ocean SST during the November-December-January (hereinafter referred to as ND(-1)J) period, approximately 9 months prior to harvest, account for 16 % of the anomaly in US soybean yields. Furthermore, for each standard deviation change in the Indian Ocean Basin (IOB) index, there is an estimated 4.0 % change in total soybean production in the United States. The root zone soil moisture and maximum temperature during the reproductive growth stage in summer are the key factors influencing the United States soybean yields. The warming of the Indian Ocean could cause hot and dry conditions during July-August-September (JAS) by influencing ND(-1)J soil moisture and the eastern Pacific SST, leading to substantial soybean failures in the United States. Our findings emphasize the importance of the Indian Ocean SST on soybean production in the United States and reveal the pathways of this impact, which can help predict the United States soybean failures and improve food security worldwide.

Source

EARTH SYSTEM DYNAMICS

Volume16Issue6Page2187-2199

DOI10.5194/esd-16-2187-2025

2025Äê12ÔÂ

Surface Warming Over Greenland Amplified by Remote Forcing From Tropical Atlantic

Duan Zhang, David M. Holland, Zhen-Qiang Zhou, Yao Yao, Yurong Hou, Xichen Li

Abstract

During the satellite era, Greenland's surface air temperature has experienced a rapid warming trend, potentially lengthening the melting season and enhancing surface melting, contributing to ice mass loss. While previous studies have primarily attributed this warming to greenhouse gas forcing, regional feedbacks, and remote forcing from the tropical Pacific, the role of the Atlantic Ocean remains less explored. Using both observations and numerical model simulations, this study identifies an atmospheric teleconnection pattern triggered by tropical North Atlantic (TNA) sea surface temperature (SST) variability, which significantly contributes to surface warming over Greenland. This teleconnection exhibits strong seasonality, with a more pronounced connection during boreal winter and spring. Anomalous TNA warming initiates a poleward-propagating Rossby wave train, inducing regional circulation adjustments that intensify thermal and moisture advection to Greenland. Enhanced downward long-wave radiation, associated with these moisture changes, further amplifies the warming trend. These findings provide valuable insights into the warming of Greenland and, by extension, its potential implications for global sea level rise. Moreover, the identified teleconnection may improve the predictability and future projections of Greenland's climate.

Source

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES

Volume130Issue24

DOI10.1029/2025JD044154

2025Äê12ÔÂ

Impact of Tropical Atlantic Sea Surface Temperature Variability on Boreal Autumn Sea Ice Concentration Over the Beaufort Sea

Yonghao Wang, Yurong Hou, Yujie Miao, Kai Man, Weihan Ma, Zhen-Qiang Zhou, Xichen Li

Abstract

This study investigates the influence of tropical Atlantic sea surface temperature (SST) variability on boreal autumn (August-September-October, ASO) sea ice concentration (SIC) in the Beaufort Sea. Although Arctic warming and sea ice retreat have been well-documented, the influence of tropical Atlantic SST on Arctic sea ice remains understudied. Using reanalysis data sets and model simulations, we demonstrate that tropical Atlantic warming significantly reduces Beaufort Sea SIC. This warming triggers a Rossby wave train that propagates northeastward, altering the high-latitude atmospheric circulation and inducing southerly flow anomalies. These anomalies enhance moisture transport, increase cloud cover, and amplify downward longwave radiation accelerating sea ice melt. Our findings, supported by Community Atmosphere Model version 5 and Community Earth System Model simulations, highlight the crucial role of tropical-Arctic teleconnections in Arctic sea ice variability.

Source

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS

Volume130Issue12

DOI10.1029/2025JC022640

2025Äê12ÔÂ

Half-Century Observations Reveal Slow and Pulsed Recovery from Heavy Mercury Pollution in a Major Temperate River      

Maodian Liu, Qianru Zhang, A. Zhulidov, T. Gurtovaya, Xingrui Cai, Wenzhe Guo, Lyudmila S. Kosmenko, N. A. Pavlova, Hehao Qin, Vladimir V. Shamov, A. Shiklomanov, I. Volkov, Xuejun Wang, Changhao Xiao, Zhihao Zhang, Sergey V Berdnikov, Peter A. Raymond

Abstract

Rivers deliver substantial mercury to coastal oceans, significantly impacting seafood safety. However, the time frame for mercury levels and fluxes in large rivers to return to a stable, low-pollution state following long-term industrial pollution remains unclear. The Amur River, the world's fifth longest and one of the largest temperate rivers, originates in Mongolia and flows along the China-Russia border. Heavy industrial wastewater discharges in the 1960s-1970s severely contaminated the river, while strict controls implemented in the late 1970s created a rare opportunity to evaluate how quickly a large river recovers from severe anthropogenic mercury pollution. Here, we present an unprecedented 43-year time series of monthly observations of particulate mercury export to determine the river's recovery time frame. We find that mercury concentrations at the river mouth tripled due to wastewater discharges. After a 90% cut in wastewater discharges, mercury levels remained at peak levels for four years, returning to near-background within approximately 15 years, representing the initial flushing of mobile mercury from the drainage network ("Baseline Recovery"). However, after the initial flushing, legacy mercury from historic wastewater discharges was remobilized by hydrologic events, triggering episodic pulses ("Disturbance Recovery") that peaked similar to 20 years after controls and reached up to three times the levels of the 1960s-1970s industrial peak. This remobilization was driven by agricultural expansion that enhanced soil disturbance and erosion, compounded by intensified droughts followed by heavy rainfall. This study provides evidence of slow and pulsed recovery of mercury fluxes in heavily polluted large rivers, highlighting that historical Hg pollution in some major rivers has likely been underestimated and reinforcing the need for sustainable, long-term management.

Source

ENVIRONMENTAL SCIENCE & TECHNOLOGY

Volume60Issue1Page609-621

DOI10.1021/acs.est.5c09152

2025Äê12ÔÂ

Local atmospheric forcing dominates the panthalassa/pacific mid-latitude decadal variability    

Sheng Wu, Yingying Zhao, Yongyun Hu, Yonggang Liu,Jian Zhang,Anni Zhao,Qin Wen,Xiang Li,Shuai Yuan,Zihan Yin

Abstract

The Pacific Decadal Variability (PDV) is an important factor that significantly influences regional and global climate changes for modern climate. However, the mechanisms behind PDV remain a subject of ongoing debate, on which the investigation of PDV for land-sea configurations different from now may shed light. In this study, PDV dynamics for three typical land-sea configurations are investigated: the Mississippian, Triassic, and Preindustrial experiments. Specifically, we analyze the relative contributions of atmospheric and oceanic forcings to PDV and investigate how local and remote factors influence its variability. The findings reveal that PDV is primarily driven by local atmospheric forcing, while oceanic heat transport plays a minor role. These findings provide new insights into the underlying mechanisms governing PDV, especially for different land-sea configurations, advancing our understanding of its role in Earth's climate system.

Source

GLOBAL AND PLANETARY CHANGE

Volume255

DOI10.1016/j.gloplacha.2025.105095

2025Äê12ÔÂ

Preface to the Special Issue on Atmospheric and Oceanic Processes in the Antarctic and Their Climate Effects: 40 Years of CHINARE      

Zhaomin Wang, Bingyi Wu, Wen Zhou, Jiping Liu, Anmin Duan, Xianyao Chen, Ruibo Lei, Minghu Ding, Xichen Li & Wenju Cai

Abstract

In November 1984, China launched its first expedition to the Southern Ocean and the Antarctic continent, culminating in the establishment of its first year-round research stationGreat Wall Stationon the Antarctic Peninsula in February 1985. Forty years later, in February 2024, China's fifth research station, Qinling Station, commenced operations on Inexpressible Island near Terra Nova Bay. Since that first mission, China's Antarctic scientific expeditions have achieved remarkable accomplishments by training a large number of scientists, fostering active international collaboration, and making significant contributions to better understanding Antarctic processes and their global impacts. This special issue marks and celebrates four decades of China's scientific engagement in Antarctica.

Source

ADVANCES IN ATMOSPHERIC SCIENCES

Volume42Issue12Page2395-2398Special IssueSI

DOI10.1007/s00376-025-5017-1

2025Äê12ÔÂ

Future Sea Surface Temperature as a Key Driver of Antarctic Warming  

Zihuan Zhang, Sai Wang, Deliang Chen, Xichen Li, Tingfeng Dou, Cunde Xiao, Wen Chen, Dahe Qin, Minghu Ding

Abstract

Polar amplification-the phenomenon whereby anthropogenic warming is accentuated relative to the global average-has emerged as a central focus of climate research. While Arctic amplification is well-established, the presence and drivers of Antarctic amplification remain contentious. Using Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations, we demonstrate a robust emergence of Antarctic amplification under the 2 degrees C goal of the Paris Agreement. Sensitivity experiments identify a pivotal role for sea surface temperature (SST) changes in mediating this anthropogenic response. Positive SST anomalies influence Antarctic temperature through dynamic and thermodynamic processes, exerting distinct and contrasting effects. Dynamic processes, characterized by intensification of the Southern Annular Mode (SAM), generally induce continental-scale cooling. In contrast, thermodynamic processes, specially through enhanced sensible and latent heat fluxes, take precedence over the dynamic effect and drive widespread warming. In a warming climate, these thermodynamic processes are expected to intensify substantially, thereby amplifying the anthropogenic climate signal over Antarctica.

Source

GEOPHYSICAL RESEARCH LETTERS

Volume52Issue24

DOI10.1029/2025GL118958