Global and Planetary Change最新文献_第8页

The impacts of volcanism on hydrocarbon-bearing sedimentary basins - Examples from the world-class Neuquén Basin case study, Argentina 火山作用对含油气沉积盆地的影响——以阿根廷neuquacimen盆地为例

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-07 DOI: 10.1016/j.gloplacha.2025.105218

Olivier Galland , Sabina Chiacchiera , Hernán de la Cal , Dougal A. Jerram , Ezequiel Lombardo , J. Octavio Palma , Gisel Peri , Ole Rabbel , Juan B. Spacapan , Maria Dolores Vallejo , Daniel Yagupsky , Alain Zanella

The last two decades of research have highlighted that volcanism occurring in sedimentary basins can have substantial effects on sedimentary formations. In particular, igneous intrusions can trigger the generation of large amounts of greenhouse gases in organic-rich host rocks, leading to dramatic climate change and mass extinctions. Volcanism can also have significant impacts on hydrocarbon-bearing sedimentary basins. The Neuquén Basin, Argentina, is a well-studied example of a hydrocarbon-producing sedimentary basin hosting massive volcanism. The combination of substantial industry subsurface data and high-quality outcrops makes the Neuquén Basin an exceptional geological object to study magma-sedimentary rock interactions and their implications to hydrocarbon systems. This contribution reviews well-studied examples from the Neuquén Basin that illustrate: (1) thermal effects of sills on maturation of the organic matter of the source rock, (2) fracturing processes in igneous intrusions and the host rock, (3) sills as producing fractured reservoirs, (4) intrusion-induced doming as structural trap or as potential fractured reservoir, (5) fluid migration along igneous intrusions, (6) reservoir compartmentalization induced by dykes, (7) generation of bitumen dykes in vicinity of intrusions, and (8) improvement of geophysical imaging using large-scale outcrops.

All in all, our review documents various effects of magma-rock interactions in hydrocarbon-bearing sedimentary basins, and highlights the significant scientific value of the Neuquén Basin as a world-class case study for unravelling processes of magma-rock interactions in hydrocarbon-bearing sedimentary basins.

过去二十年的研究强调，发生在沉积盆地的火山活动可以对沉积地层产生重大影响。特别是，火成岩侵入可以在富含有机物的宿主岩石中引发大量温室气体的产生，导致剧烈的气候变化和大规模物种灭绝。火山作用对含油气沉积盆地也有重要影响。阿根廷的neuquacimen盆地是一个被充分研究的产烃沉积盆地，它拥有大量的火山活动。大量的工业地下数据和高质量的露头相结合，使neuqun盆地成为研究岩浆-沉积岩相互作用及其对油气系统意义的特殊地质对象。这篇文章回顾了neuquacimen盆地的一些得到充分研究的例子，这些例子说明：(1)基岩热作用对烃源岩有机质成熟的影响；(2)火成岩侵入体与寄主岩的压裂过程；(3)基岩形成裂缝性储层；(4)侵入诱导的丘顶作为构造圈闭或潜在裂缝性储层；(5)流体沿火成岩侵入体运移；(6)岩脉诱导的储层分区化；(7)侵入体附近沥青岩脉的生成；(8)大规模露头物探成像技术的改进。总而言之，我们的综述记录了含油气沉积盆地中岩浆-岩石相互作用的各种影响，并强调了neuquacimen盆地作为揭示含油气沉积盆地岩浆-岩石相互作用过程的世界级案例研究的重要科学价值。

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引用次数: 0

Understanding green house gases emission dynamics from forest fires in Thailand using predictive models 利用预测模型了解泰国森林火灾的温室气体排放动态

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-07 DOI: 10.1016/j.gloplacha.2025.105236

Fahad Shahzad , Kaleem Mehmood , Shoaib Ahmad Anees , Muhammad Adnan , Khadim Hussain , Waseem Razzaq Khan , Munawar Shah , Punyawi Jamjareegulgarn , Manuela Oliveira , José G. Borges

Forest fires are a major driver of carbon emissions, particularly in tropical regions where climate variability and land use practices intensify their frequency and impact. This study investigates the spatiotemporal trends and emission dynamics of forest fires across Thailand's three dominant vegetation types- Evergreen Broadleaf Forest (EBF), Deciduous Broadleaf Forest (DBF), and Grassland over three climatic seasons (Dry, Hot, and Wet) in the period 2001–2023. Using the Mann-Kendall trend test and Sen's Slope estimator, we observed significant declines in burnt area during the Dry season in EBF and Grasslands, with no consistent trend in DBF. Fire–vegetation interactions revealed seasonally specific effects: positive correlations between fire count and Net Primary Productivity (NPP) were detected in the Wet and the hot seasons in the case of DBF and Grasslands, respectively. Emission analysis showed that CO₂ was the dominant greenhouse gas released, with the Dry season contributing to most emissions, although Hot season emissions have increased over time. Machine learning models Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) explained over 78 % of the variance in CO₂ emissions on test data (R² = 0.79 for RF, 0.78 for XGBoost), despite higher Root Mean Square Error (RMSE) values (∼550) on unseen data. The Shapley Additive Explanations (SHAP) analysis identified wind components and solar radiation as key predictive variables. Central, Northeastern, and Northern Thailand emerged as emission hotspots. These findings improve our understanding of emission dynamics from tropical fires and underscore the need for region-specific mitigation strategies to inform carbon inventories and climate policy.

森林火灾是碳排放的主要驱动因素，特别是在气候变化和土地利用做法加剧其发生频率和影响的热带地区。本文研究了2001-2023年泰国三种主要植被类型——常绿阔叶林（EBF）、落叶阔叶林（DBF）和草地在干热湿三个气候季节的森林火灾时空变化趋势和排放动态。利用Mann-Kendall趋势检验和Sen’s Slope估计，我们观察到干旱季EBF和草地的燃烧面积显著减少，而DBF的趋势不一致。火-植被相互作用表现出季节特异性效应：在湿季和热季，林火数量与净初级生产力（NPP）分别呈显著正相关。排放分析表明，二氧化碳是主要的温室气体释放，旱季贡献了大部分排放，尽管炎热季节的排放量随着时间的推移而增加。机器学习模型随机森林（RF）和极端梯度增强（XGBoost）解释了测试数据中超过78%的CO₂排放差异（RF R2 = 0.79, XGBoost R2 = 0.78），尽管未见数据的均方根误差（RMSE）值更高（约550）。Shapley加性解释（SHAP）分析确定风成分和太阳辐射是关键的预测变量。泰国中部、东北部和北部成为排放热点。这些发现提高了我们对热带火灾排放动态的理解，并强调需要制定针对特定区域的缓解战略，为碳清单和气候政策提供信息。

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引用次数: 0

Miocene carbonate crash in the eastern Pacific: A catalyst for early rare earth element enrichment 东太平洋中新世碳酸盐碰撞：早期稀土元素富集的催化剂

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-07 DOI: 10.1016/j.gloplacha.2025.105235

Yayue Tang , Dengfeng Li , Fei Huang , Rui Wang , Jiewei Hu , Jinzhou Peng , Yu Fu , Xiaoming Sun

Rare earth element and yttrium (REE + Y = REY) are critical and strategic resources due to their significant role in various industries, making exploring new REY resources and studying the enrichment mechanisms important. Deep-sea REY-rich sediments are primarily found in siliceous deposits below the carbonate compensation depth (CCD), however, the causative mechanisms for negative correlation between REY enrichment and carbonate content remain unclear. Here, we select a period of REY enrichment (from 20 Ma) from International Ocean Discovery Program (IODP) Site U1334 that coincides with carbonate crash and focus on analyzing the influence of carbonate dissolution on REY enrichment in sediments from the Eastern Equatorial Pacific (EEP) and their associated environment changes. Prior to 15 Ma, REY contents range from 47 to 253 ppm, average at 125 ppm. Neodymium isotope (εNd) of fish debris was used to construct the evolution of deep water in EEP. The values (−4.3 to −3.5; avg. −3.8) indicate sluggish deep-water circulation under warm climate conditions, coinciding with a gradual carbonate accumulation rate (CAR) decline. While after 15 Ma, more radiogenic εNd ranged from −5.1 to −3.3, alongside Ti/Al average ratio increased from 2.56 to 2.71 and near zero CAR, reflecting stronger, more corrosive bottom waters and intensified silicate weathering driven by cooling and ice-sheet expansion, and finally the carbonate content depleted at 11 Ma. Meanwhile, average REY contents increase from 311 (∼ 15–11 Ma) to 623 ppm after 11 Ma, with accompanied by a rise in TOC and δ Ce from 0.02 to 0.13 % and 0.12–0.19 %, respectively. Our findings offer new constraints on the triggers of the Miocene carbonate crash and REY enrichment which is under the ultimate influence of carbonate dissolution during the Miocene, and capture the ongoing process of REY enrichment with organic matter burial.

稀土元素和钇（REE + Y = REY）在各行业中发挥着重要作用，是重要的战略资源，勘探新的REY资源和研究富集机制具有重要意义。深海富REY沉积物主要分布在碳酸盐补偿深度（CCD）以下的硅质沉积物中，但REY富集与碳酸盐含量负相关的机理尚不清楚。本文选取了国际海洋发现计划（IODP） U1334站点中与碳酸盐碰撞相吻合的20 Ma的REY富集期，重点分析了碳酸盐溶解对东赤道太平洋（EEP）沉积物中REY富集的影响及其相关环境变化。在15 Ma之前，REY含量范围为47至253 ppm，平均值为125 ppm。利用鱼屑的钕同位素（εNd）构建了EEP深水演化。该数值（- 4.3 ~ - 3.5，平均值为- 3.8）表明在温暖气候条件下深水环流缓慢，与碳酸盐积累速率（CAR）逐渐下降相一致。15 Ma后，辐射成因εNd在−5.1 ~−3.3之间变化，Ti/Al平均比值从2.56增加到2.71，CAR接近于零，反映了冷却和冰盖膨胀驱动的底部水更强、腐蚀性更强和硅酸盐风化加剧，最终在11 Ma时碳酸盐含量耗尽。11 Ma后，平均REY含量从311（~ 15 ~ 11 Ma）上升到623 ppm， TOC和δ Ce分别从0.02 ~ 0.13 %上升到0.12 ~ 0.19 %。研究结果为中新世碳酸盐碰撞和REY富集的成因提供了新的约束条件，REY富集最终受中新世碳酸盐溶蚀作用的影响，并捕捉到了REY富集与有机质埋藏的持续过程。

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引用次数: 0

Permafrost dampens long-term vegetation responses to climate change in northern Siberia: Evidence from pollen spectra covering the last 40 kyr 西伯利亚北部永久冻土带抑制植被对气候变化的长期响应：来自覆盖过去40年的花粉谱的证据

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-06 DOI: 10.1016/j.gloplacha.2025.105237

Zitong Wang , Chen Liang , Kai Chen , Xianyong Cao

Understanding long-term interactions between climate, permafrost, and vegetation provides an essential context for interpreting current Arctic greening. Using 65 fossil pollen records from northern Siberia and a Random Forest model trained on a dataset of 835 modern pollen–climate assemblages, we quantitatively reconstructed mean temperature of the warmest month (Mtwa: mean July temperature) anomalies over the past 40 thousand years (ka) and assessed associated vegetation changes. During the Last Glacial Period, herbaceous taxa overwhelmingly dominated, and warming of ∼1 °C during ∼40–35 cal ka BP was insufficient to deepen the active layer beyond the threshold required for tree establishment, leaving woody cover minimal. In the early Holocene, sustained warming of nearly 2 °C triggered permafrost degradation and active-layer thickening, enabling forest expansion, although tree taxa lagged shrubs by several millennia. These results reveal a clear threshold effect in vegetation–permafrost interactions and show that only sustained warming can overcome permafrost constraints. By providing quantitative temperature estimates, our reconstruction offers critical benchmarks for predicting how ongoing Arctic warming may transform vegetation patterns and permafrost stability.

了解气候、永久冻土和植被之间的长期相互作用为解释当前的北极绿化提供了一个重要的背景。利用来自西伯利亚北部的65份花粉化石记录和基于835份现代花粉-气候组合数据集的随机森林模型，我们定量地重建了过去4万年（ka）最温暖月份的平均温度（Mtwa: 7月平均温度）异常，并评估了相关的植被变化。在末次冰期，草本类群占绝对优势，在~ 40-35 cal ka BP期间的~ 1°C升温不足以使活性层加深到超过树木生长所需的阈值，使木质覆盖最小。在全新世早期，近2°C的持续变暖引发了永久冻土退化和活动层增厚，使森林得以扩张，尽管乔木类群落后于灌木几千年。这些结果揭示了植被-永久冻土相互作用中明显的阈值效应，并表明只有持续变暖才能克服永久冻土的限制。通过提供定量的温度估计，我们的重建为预测持续的北极变暖如何改变植被模式和永久冻土稳定性提供了关键的基准。

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引用次数: 0

Millennial-scale precipitation isotope variability reveals spatial heterogeneity in Asian monsoon moisture during the last glacial period 千年尺度降水同位素变异揭示末次冰期亚洲季风水汽的空间异质性

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-06 DOI: 10.1016/j.gloplacha.2025.105228

Yasi Huang , Fan Zhang , Zheng Wang , Yunning Cao , Jing Hu , Qian Li , Xu Liu , Jibao Dong , Hongxuan Lu , Huangye Wang , Meng Xing , Hu Liu , Weiguo Liu

Millennial-scale climate variability (MCV) in the Asian summer monsoon (ASM) plays a crucial role in elucidating short-term monsoon dynamics and in improving projections of future Asian hydroclimate change. However, significant divergences remain in our understanding of how high- and low-latitude climate systems couple to drive and modulate MCV in ASM precipitation. These discrepancies primarily arise from a limited understanding of the spatial heterogeneity in precipitation MCV in marginal ASM regions. We present a new high-resolution (∼280-year) loess leaf-wax hydrogen isotope (δDwax) record from the central Chinese Loess Plateau (CLP) spanning the last glacial period. The record reconstructs regional precipitation isotopic variability on precessional and millennial timescales. The strong correspondence between the CLP δDwax record and 65°N summer insolation demonstrates that orbital-scale variations in precipitation δD across ASM marginal regions primarily reflect high-latitude insolation forcing. On millennial timescales, although the MCV of Xifeng (XF) precipitation δD exhibits characteristics modulated by the precession periodicity, its exceptionally low mean absolute amplitude indicates that this modulating effect was significantly attenuated in this region during the last glacial period. Synthesis of precipitation isotope records across the monsoon region reveals complex spatial heterogeneity in the amplitude of MCV during the last glacial period. The Indian monsoon–affected region exhibits greater MCV overall than the East Asian monsoon–dominated region. Although both monsoon systems exhibit a trend of strengthening amplitude along their respective moisture transport pathways, MCV amplitudes decrease in the transitional zone. This pattern suggests that these regions were situated beyond the ASM marginal zone during the glacial period. Our findings further underscore that the pathways and strengths of moisture transport critically govern the spatial heterogeneity of monsoon precipitation MCV, revealing a glacial-state hydroclimate pattern where a region's response amplitude is dictated by its relative position on the moisture pathway.

亚洲夏季风（ASM）的千年尺度气候变率（MCV）在阐明短期季风动力学和改善未来亚洲水文气候变化预测方面起着至关重要的作用。然而，我们对高纬度和低纬度气候系统如何耦合驱动和调节大西洋平流层降水中的MCV的理解仍然存在重大分歧。这些差异主要是由于对边缘地区降水MCV的空间异质性认识有限。我们提出了一个新的高分辨率（~ 280年）黄土叶蜡氢同位素（δDwax）记录，来自中国中部黄土高原（CLP）跨越末次冰期。该记录在岁差和千年时间尺度上重建了区域降水同位素变化。CLP δDwax记录与65°N夏季日晒的强烈对应表明，大西洋洋边缘地区降水δD的轨道尺度变化主要反映高纬度日晒强迫。在千禧年时间尺度上，西峰降水δD的MCV虽然表现出岁差周期调制的特征，但其异常低的平均绝对幅值表明这种调制作用在末次冰期显著减弱。对整个季风区降水同位素记录的综合分析揭示了末次冰期MCV振幅的复杂空间异质性。印度受季风影响地区总体上表现出比东亚季风主导地区更大的MCV。尽管两个季风系统在各自的水汽输送路径上都表现出振幅增强的趋势，但在过渡带，MCV振幅减小。这一模式表明，这些地区在冰期位于亚欧大陆边缘带之外。我们的研究结果进一步强调了水汽输送的途径和强度对季风降水MCV的空间异质性起着关键的控制作用，揭示了一种冰川状态水文气候模式，其中一个地区的响应幅度取决于其在水汽输送途径上的相对位置。

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引用次数: 0

Modelling wildfire and post-fire carbon budgets of a boreal forest under a changing climate 气候变化下北方森林野火和火灾后碳收支模型

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-06 DOI: 10.1016/j.gloplacha.2025.105230

Md. Rafikul Islam , Lars Nieradzik , Julia Kelly , Anna Maria Jönsson , Natascha Kljun

Understanding the dynamics of post-fire carbon recovery is critical for managing boreal forests under climate change. This study evaluates the LPJ-GUESS-BLAZE models' performance in simulating vegetation structure, fire emissions, and post-fire carbon dynamics at the stand scale in a boreal forest in Sweden. Combining current climate and future scenarios (SSP1–2.6, SSP5–8.5), we investigated the impacts of post-fire management strategies, including no management and different reforestation options, on the forest carbon balance. Our results showed that the model accurately simulated unburnt vegetation structure. However, it overestimated fire carbon emissions compared to in-situ estimates. Post-fire carbon flux simulations revealed that avoiding salvage-logging of fire-surviving trees could result in the highest net carbon uptake in the near future (2019–2060). Reforestation strategies with a combination of conifer and broad-leaved trees consistently resulted in higher net C uptake than monoculture or mixed conifer options across all scenarios. Warming scenarios further accelerated carbon recovery, reducing the years needed to reach the carbon compensation point (CCP), i.e. the time when cumulative carbon uptake by reforestation balances the total carbon lost due to fire and post-fire emissions. Nevertheless, our study also revealed that the modelled rate of forest recovery was more rapid than observed. Our findings suggest that addressing specific model issues (e.g. fuel load and early stand development) can increase the robustness of modelled fire carbon emissions and CCP estimates.

了解火灾后碳恢复的动态对于管理气候变化下的北方森林至关重要。本研究评估了LPJ-GUESS-BLAZE模型在模拟瑞典北方森林林分尺度植被结构、火灾排放和火灾后碳动态方面的性能。结合当前气候和未来情景（SSP1-2.6, SSP5-8.5），研究了火灾后管理策略（包括不管理和不同的造林方案）对森林碳平衡的影响。结果表明，该模型能较准确地模拟未燃烧植被结构。然而，与现场估计相比，它高估了碳排放量。火灾后碳通量模拟显示，在不久的将来（2019-2060年），避免对火灾幸存树木的回收砍伐可能会导致最高的净碳吸收量。在所有情况下，针叶树和阔叶树相结合的再造林策略始终比单一种植或混合针叶树方案产生更高的净碳吸收量。变暖情景进一步加速了碳的恢复，减少了达到碳补偿点（CCP）所需的时间，即重新造林累积的碳吸收平衡由于火灾和火灾后排放造成的总碳损失的时间。然而，我们的研究还表明，模拟的森林恢复速度比观测到的要快。我们的研究结果表明，解决特定的模型问题（例如燃料负荷和早期林分发展）可以增加模型碳排放和CCP估计的稳健性。

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引用次数: 0

Astronomical control on marine anoxia during the Kellwasser Crisis and Rhinestreet Event (Appalachian Basin, New York, USA) Kellwasser危机和rhinestet事件期间海洋缺氧的天文控制（Appalachian Basin, New York， USA）

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-06 DOI: 10.1016/j.gloplacha.2025.105216

Jarno J.C. Huygh , Thomas J. Algeo , Bradley B. Sageman , Michiel Arts , Charles A. Ver Straeten , D. Jeffrey Over , Justin Gérard , Loïc Sablon , Michel Crucifix , Anne-Christine Da Silva

The Kellwasser Crisis near the Frasnian-Famennian boundary (∼372 Ma) is linked to one of the major Phanerozoic biodiversity crises. It is associated with sea-level changes, carbon-cycle perturbations, and pulsed oceanic anoxia, that led to black shale deposition characterized by positive carbon isotope excursions, akin to the Kellwasser horizons in Germany. Despite growing evidence of astronomically forced climatic stresses influencing Devonian marine systems, the trigger mechanism(s) of the Kellwasser Event remain debated. The West Valley core (WVC) comprises middle Frasnian to lower Famennian strata, including the Rhinestreet and Kellwasser events, characterized by black shales, elevated total organic carbon (TOC) content, and a positive δ¹³C_org carbon isotope excursion in the Kellwasser Crisis interval. In this work, we performed cyclostratigraphic analysis of Ti, Ti/Al and TOC, which reveals a strong astronomical imprint, particularly eccentricity amplitude modulation patterns. The TOC record was tuned to the stable 405-kyr eccentricity period, yielding a 5.67-Myr-long floating astrochronology, with event durations for the Rhinestreet and Kellwasser intervals consistent with previous reports. Subsequent analysis confirmed an equally strong eccentricity imprint on the titanium content, strongly implying a link between organic matter preservation, detrital sediment supply and astronomical forcing. Additionally, a dominant imprint of the 1.2-Myr and 2.4-Myr obliquity cycles on sea-level variation supports astronomical control on the Kellwasser Crisis. Finally, new insights into the phase relationship between the Rhinestreet and Kellwasser events and astronomically forced climate changes are globally contextualized within a new cyclostratigraphic model, emphasizing the role of eccentricity and obliquity in pacing marine anoxia.

靠近Frasnian-Famennian边界（~ 372 Ma）的Kellwasser危机与显生宙生物多样性危机之一有关。它与海平面变化、碳循环扰动和脉冲海洋缺氧有关，导致以正碳同位素漂移为特征的黑色页岩沉积，类似于德国的Kellwasser层位。尽管越来越多的证据表明天文强迫气候压力影响泥盆纪海洋系统，但凯尔瓦瑟事件的触发机制仍存在争议。西谷岩心（WVC）为中弗拉斯统至下法门统地层，包括Rhinestreet和Kellwasser事件，以黑色页岩为特征，总有机碳（TOC）含量升高，Kellwasser危机段δ 13g碳同位素正偏移。在这项工作中，我们进行了Ti、Ti/Al和TOC的旋回地层分析，揭示了强烈的天文印记，特别是偏心振幅调制模式。TOC记录被调整到稳定的405 kyr离心周期，产生了5.67 myr长的浮动天体年表，其中Rhinestreet和Kellwasser间隔的事件持续时间与之前的报告一致。随后的分析证实了钛含量上同样强烈的偏心印记，有力地暗示了有机物保存、碎屑沉积物供应和天文强迫之间的联系。此外，1.2-Myr和2.4 myr倾角旋回对海平面变化的主要影响支持了对Kellwasser危机的天文控制。最后，在一个新的旋回地层模型中，对Rhinestreet和Kellwasser事件与天文强迫气候变化之间的相位关系有了新的认识，强调了偏心率和倾角在调节海洋缺氧中的作用。

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引用次数: 0

Continuous Atlantic Water advection to the western Fram Strait since the Late glacial 自晚冰期以来，大西洋水持续向西弗拉姆海峡平流

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-06 DOI: 10.1016/j.gloplacha.2025.105219

Maciej M. Telesiński, Dhanushka Devendra, Marek Zajączkowski

The Fram Strait is the primary gateway between the Arctic and global oceans, critically influencing ocean circulation and climate dynamics. While the eastern Fram Strait has been well studied, its western part remains underexplored due to persistent sea-ice cover and carbonate dissolution challenges. This study presents a multiproxy analysis of six sediment records, including two new cores, along the East Greenland shelfbreak to reconstruct the Atlantic Water (AW) advection since the Late Glacial (∼35 ka BP). Results indicate a continuous AW presence, with enhanced inflow during Marine Isotope Stage 3, fostering open-water conditions and aiding regional ice sheet growth. The early Last Glacial Maximum saw high productivity and persistent AW inflow, while deeper halocline conditions constrained AW to subsurface layers. Deglaciation initiated around 19 ka BP, marked by meltwater pulses that impacted AW pathways and oceanic stratification. During Heinrich Stadial 1 and the Younger Dryas, AW was forced deeper, retaining subsurface warmth despite surface cooling. The Holocene transition brought spatially asynchronous warming and foraminiferal flux increases, but AW inflow remained relatively steady. However, localized changes, including increased meltwater and weakened east-west recirculation, modulated its surface impact. This study underscores the complex interplay between AW advection, sea ice, meltwater dynamics, and atmospheric forcing in shaping the paleoceanography of the western Fram Strait. Despite a persistent AW signal, surface environmental conditions varied significantly in response to regional and hemispheric climate drivers, often in contrast to the eastern Fram Strait.

弗拉姆海峡是北极和全球海洋之间的主要门户，对海洋环流和气候动态具有重要影响。虽然弗拉姆海峡东部已经得到了很好的研究，但由于持续的海冰覆盖和碳酸盐溶解的挑战，其西部仍未得到充分开发。本研究对东格陵兰断裂带的6个沉积物记录（包括两个新岩心）进行了多代理分析，以重建晚冰期（~ 35 ka BP）以来的大西洋水（AW）平流。结果表明，在海洋同位素阶段3，AW持续存在，流入增强，形成了开放水域条件，促进了区域冰盖的生长。末次盛冰期早期的高生产力和持续的AW流入，而更深的盐斜条件将AW限制在次表层。冰川消融开始于19ka BP左右，其标志是融水脉冲影响了AW路径和海洋分层。在海因里希第1期和新仙女木期期间，阿瓦被逼得更深，尽管地表变冷，但仍保持着地下的温暖。全新世转变带来了空间非同步增温，有孔虫通量增加，但AW流入保持相对稳定。然而，局部变化，包括融水增加和东西再循环减弱，调节了其对地表的影响。这项研究强调了平流、海冰、融水动力学和大气强迫在塑造海峡西部古海洋学中的复杂相互作用。尽管存在持续的AW信号，但地表环境条件对区域和半球气候驱动因素的响应发生了显著变化，通常与海峡东部相反。

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引用次数: 0

Decoupling of the relationship between canopy and stem growth in broadleaf trees under humid conditions 湿润条件下阔叶树冠层与树干生长关系的解耦

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-05 DOI: 10.1016/j.gloplacha.2025.105233

Shengjie Wang , Chenxi Xu , Yuanqiao Li , Jiayan Shen , Jia Tang , Shuai Yuan

Tree stems act as the primary carbon storage organs, with leaf growth variability regulating storage intensity. However, how environmental factors influence carbon storage via leaf growth remains unclear. This study examines the relationship between tree stem growth (tree-ring width index, RWI) and leaf growth (normalized difference vegetation index, NDVI) across different forest types globally. We analyzed the potential influencing factors of this relationship and identified the pathway from environmental conditions to leaves and then stems. We found that MODIS NDVI, with higher spatial resolution, better reflects stem growth in broadleaf forests, while GIMMS NDVI, with a longer time series, is more effective in characterizing stem growth in coniferous forests. Forest type and moisture availability are the dominant factors shaping the leaf-stem growth relationship. Coniferous trees growing under increasingly drier conditions, with higher tree density and poorer soil fertility, tend to exhibit a stronger coupling between leaf and stem growth. Further analysis showed that in moist environments, especially in broadleaf forests, leaf and stem growth become increasingly decoupled. In contrast, conifers maintain stronger coordination. This may be related to trade-offs in resource allocation driven by the varying relative importance of external environmental stress and internal biological connections affecting leaf and stem growth under different moisture conditions. Leaf growth is influenced by soil moisture, soil temperature, and air temperature, but their relative contributions vary across forest types and moisture regimes. These findings suggest caution when using leaf growth (e.g., NDVI) as a proxy for forest productivity in humid broadleaf ecosystems, where decoupling may mask actual carbon allocation patterns.

树干是主要的碳储存器官，叶片生长变异性调节碳储存强度。然而，环境因素如何通过叶片生长影响碳储量尚不清楚。本研究考察了全球不同森林类型的树干生长（树轮宽度指数，RWI）和叶片生长（归一化植被指数，NDVI）之间的关系。分析了影响这一关系的潜在因素，确定了从环境条件到叶片再到茎的途径。研究发现，MODIS NDVI具有较高的空间分辨率，能较好地反映阔叶林的树干生长情况，而GIMMS NDVI具有较长的时间序列，能较好地反映针叶林的树干生长情况。森林类型和水分有效性是影响叶干生长关系的主要因素。针叶树生长在日益干燥的条件下，树密度较高，土壤肥力较差，叶和茎之间的耦合更强。进一步分析表明，在湿润环境中，尤其是阔叶林，叶和茎的生长越来越不耦合。相比之下，针叶树保持更强的协调性。这可能与不同湿度条件下影响叶片和茎生长的外部环境胁迫和内部生物连接的相对重要性不同所驱动的资源分配权衡有关。叶片生长受土壤湿度、土壤温度和空气温度的影响，但它们的相对贡献因森林类型和湿度制度而异。这些发现表明，在湿润阔叶生态系统中，使用叶片生长（如NDVI）作为森林生产力的代表时要谨慎，因为解耦可能掩盖了实际的碳分配模式。

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引用次数: 0

Spatial and climate dependency of water isotope fractionation between precipitation and vapor in East Asia based on explainable machine learning 基于可解释机器学习的东亚降水和水汽之间水同位素分馏的空间和气候依赖关系

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2025-12-05 DOI: 10.1016/j.gloplacha.2025.105213

Kun Liu , Shengjie Wang , Jinzhao Liu , Kei Yoshimura , Haixiang Jie , Yudong Shi , Shijun Lei , Yao Cheng , Liwei Wang , Mingjun Zhang

Stable hydrogen and oxygen isotopes are effective tracers in the hydrological and atmospheric processes in the Earth system sciences. Stable water isotope fractionations between precipitation and water vapor are usually assumed in an equilibrium or non-equilibrium situation. However, due to the limited synchronous observations, the spatial and climate dependency of equilibrium versus non-equilibrium fractionation models under natural conditions remains insufficiently assessed. In this study, we compiled over 19,000 precipitation isotope records across East Asia and reconstructed vapor isotopes using both equilibrium and non-equilibrium models. Our results show that the non-equilibrium model performs better near the surface at the daily scale (r > 0.7), particularly under low-humidity conditions, but its accuracy decreases with altitude. Further analysis using the classification prediction (LightGBM, area under curve > 0.8) and the SHAP (Shapley additive explanations) method identifies relative humidity as the dominant factor of model applicability. Based on Gini threshold analysis, we quantify the applicability thresholds and regional differences of fractionation models: the non-equilibrium model dominates when relative humidity is below 65%, whereas the equilibrium model is more suitable under higher humidity. The geographic boundary of the recommended fractionation models largely coincides with the transitional belt between arid and humid regions. Our findings enhance the understanding of precipitation–vapor isotope dynamics in monsoon regions like East Asia, and provide methodological guidance for isotope-based studies of the water cycle and paleoclimate.

稳定的氢和氧同位素是地球系统科学水文和大气过程中有效的示踪剂。降水和水蒸气之间的稳定水同位素分馏通常假设在平衡或非平衡状态下。然而，由于同步观测有限，平衡分馏模式与非平衡分馏模式在自然条件下的空间和气候依赖关系仍未得到充分评估。在这项研究中，我们收集了东亚地区19,000多个降水同位素记录，并使用平衡和非平衡模式重建了水汽同位素。结果表明，在日尺度（r > 0.7）下，非平衡模式在地表附近表现较好，特别是在低湿度条件下，但其精度随海拔而降低。利用分类预测（LightGBM，曲线下面积>； 0.8）和SHAP （Shapley加性解释）方法进一步分析，发现相对湿度是影响模型适用性的主要因素。基于基尼阈值分析，我们量化了分选模型的适用阈值和区域差异：相对湿度低于65%时，非平衡模型占主导地位，而相对湿度较高时，平衡模型更适用。推荐的分馏模式的地理边界与干湿过渡带基本吻合。本文的研究结果增强了对东亚季风区降水-水汽同位素动力学的认识，并为基于同位素的水循环和古气候研究提供了方法指导。

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引用次数: 0