Global and Planetary Change最新文献_第2页

Ecosystem water limitation shifts driven by soil moisture in the Loess Plateau, China 中国黄土高原土壤水分导致的生态系统水分限制变化

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-05 DOI: 10.1016/j.gloplacha.2024.104625

Xiaoru Liang , Jianwu Yan , Wei Liang , Boyan Li , Xiaohong Liu , Fulai Feng , Jia Wei

In the context of climate change, the functionality of ecosystems is primarily influenced by the availability of water and energy supply. However, there is limited research that comprehensively uses energy indicators to explore how climate change affects the water and energy limiting states of ecosystems. Here we evaluated the historical and future water and energy limitations using the Ecosystem Limitation Index (ELI) derived from evapotranspiration (ET), soil moisture (SM), net radiation (Rn), and air temperature (Ta), and conducted an in-depth analysis of the dominant factors. The results indicate that: (1) The degree of water limitation deepened initially and then weakened. Over 68 % of the region became drier initially, while over 83 % became wetter later. (2) In terms of area, soil moisture emerged as a critical factor influencing the variations in water and energy constraints within the Loess Plateau. Further research revealed the range of critical soil moisture (CSM) for the transition of water-energy limitation state is 0.286 mm³mm⁻³, and it varies with changes in temperature, soil texture, vegetation cover, and season. (3) Future projections suggest a transition towards heightened water limitations across the Loess Plateau. These findings underscore the efficacy of ELI in assessing and predicting dynamic ecosystem changes, offering valuable insights into the impacts of climate change on water and energy cycles within semi-arid ecosystems.

在气候变化的背景下，生态系统的功能主要受水和能源供应的影响。然而，全面使用能源指标来探讨气候变化如何影响生态系统的水和能源限制状态的研究却很有限。在此，我们利用由蒸散量（ET）、土壤湿度（SM）、净辐射（Rn）和气温（Ta）得出的生态系统限制指数（ELI）对历史和未来的水和能量限制进行了评估，并对主导因素进行了深入分析。结果表明(1) 水分限制程度先加深后减弱。超过 68% 的区域最初变得较干，而超过 83% 的区域后来变得较湿。(2) 就面积而言，土壤湿度是影响黄土高原水和能量限制变化的关键因素。进一步研究发现，水能限制状态过渡的临界土壤湿度（CSM）范围为 0.286 mm3mm-3，它随温度、土壤质地、植被覆盖和季节的变化而变化。(3）未来预测表明，整个黄土高原的水限制将向加剧过渡。这些发现强调了 ELI 在评估和预测生态系统动态变化方面的功效，为了解气候变化对半干旱生态系统中水和能量循环的影响提供了宝贵的见解。

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引用次数: 0

Concurrent trend turnings of drought severity across Afro-Eurasian continent since 1950 1950 年以来整个非洲-欧亚大陆干旱严重程度的并发趋势变化

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-05 DOI: 10.1016/j.gloplacha.2024.104628

Wei Lou , Cheng Sun , Bin Zuo

Rapidly intensifying global land drought poses severe threats to human societies, economies, and ecosystems. While previous studies have primarily investigated long-term drought trends, the frequency and concurrence of trend turnings have been largely neglected. In this study, we address this gap by employing the Running Slope Difference (RSD)-t-test to quantify trend turning frequency in Afro-Eurasian drought severity. Based on Palmer Drought Severity Index (PDSI), our analysis indicates that the PDSI trend in most parts of the Afro-Eurasian continent has experienced two turnings since 1950, although, the types of trend turnings vary regionally. The concurrence of these PDSI trending turnings is further investigated. Around 1985, a dipole pattern emerged - Eastern Europe experiences a drying trend turning, accompanied by decreased P-E and intensified drought, while Sahel exhibits a wetting trend turning, with increased P-E and mitigated drought. Around 2000, a tripole pattern is observed in Eastern Eurasia: The Russian Far East and South Asia experienced a drying trend turning, with reduced P-E and intensified drought, while Northeast Asia exhibited a further wetting trend, characterized by increased P-E and mitigated drought. We further investigate the influence of large-scale circulation changes. The enhanced Northern Hemisphere warming trend before and after 1985 contributes to increased land surface high pressure and an amplified meridional temperature gradient, favoring cross-equatorial water vapor transport. This mechanism potentially drives the dipole pattern of trend turning observed around 1985. Additionally, the North Pacific Ocean Sea Surface Temperature (SST) exhibited an enhanced North Pacific Gyre Oscillation (NPGO) pattern around 2000, which induced a tripole atmospheric circulation pattern over East Asia, corresponding to the observed tripole pattern of PDSI trend turnings. The identified dipole and tripole patterns of drought trend turnings, and their potential links to large-scale atmospheric circulation changes, provide insights into the complex dynamics of land drought variability across Afro-Eurasian.

迅速加剧的全球陆地干旱对人类社会、经济和生态系统构成了严重威胁。以往的研究主要调查长期干旱趋势，但趋势转折的频率和同时性在很大程度上被忽视。在本研究中，我们采用运行斜率差（RSD）-t 检验来量化非洲-欧亚干旱严重程度的趋势转折频率，从而弥补了这一空白。基于帕尔默干旱严重程度指数（PDSI），我们的分析表明，自 1950 年以来，非洲-欧亚大陆大部分地区的 PDSI 趋势经历了两次转折，尽管趋势转折的类型因地区而异。我们进一步研究了这些 PDSI 趋势转折的同时性。1985 年前后，出现了偶极模式--东欧经历了干燥趋势转向，伴随着 P-E 值下降和干旱加剧，而萨赫勒则出现了湿润趋势转向，伴随着 P-E 值上升和干旱缓解。2000 年前后，欧亚大陆东部出现了三极模式：俄罗斯远东地区和南亚出现了干燥趋势转折，P-E 下降，干旱加剧，而东北亚则进一步呈现湿润趋势，P-E 上升，干旱缓解。我们进一步研究了大尺度环流变化的影响。1985年前后北半球变暖趋势增强，导致陆面高压增加，经向温度梯度扩大，有利于水汽跨赤道输送。这一机制有可能推动 1985 年前后观测到的趋势转向偶极模式。此外，北太平洋海面温度（SST）在 2000 年前后呈现出增强的北太平洋环流涛动（NPGO）模式，这在东亚上空诱发了三极大气环流模式，与观测到的 PDSI 趋势转向三极模式相对应。已确定的干旱趋势转折的偶极和三极模式及其与大尺度大气环流变化的潜在联系，为了解整个非洲-欧亚大陆陆地干旱变化的复杂动态提供了见解。

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引用次数: 0

Siberian larch is better adapted to stress in wet-stressed areas than in drought-stressed areas 西伯利亚落叶松在湿润地区比在干旱地区更能适应压力

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-04 DOI: 10.1016/j.gloplacha.2024.104624

Peng Zhang , Liang Jiao , Ruhong Xue , Mengyuan Wei , Xuge Wang , Qian Li , Zhengdong Guo

With climate change, the frequency and intensity of wet and dry events are increasing, as is the uncertainty of their impact on tree growth. There have been studies on the effects of wet and dry conditions on tree growth, but there is a lack of comparisons of tree adaptation strategies to different types of wet and dry events in heterogeneous environments. Therefore, we explored differences in the response of tree radial growth to different types of wet and dry events using data on tree ring widths of Siberian larch (Larix sibirica) in the Altai Mountains (west) and Mongolian Plateau (east) of Central Asia. The results showed that western tree radial growth was significantly negatively correlated with precipitation and Standardized Precipitation Evapotranspiration Index (SPEI), and significantly positively correlated with mean temperature. The radial growth of trees in the east was significantly and positively correlated with precipitation and SPEI, and significantly and negatively correlated with mean temperature. Trees in wet-stressed areas are less resistance to composite cold-wet events than to ordinary wet events. Trees in drought-stressed areas are less resistance to composite hot-drought events than to ordinary drought events. Trees in the wet-stressed area recovered to normal growth levels in the first year after both ordinary wet and compound cold-wet events, and trees in the drought-stressed area failed to recover after both ordinary drought and compound hot-drought events, but then experienced compensatory growth. Thus, climate warming had a positive effect on radial growth of trees in the wet-stressed areas and a negative effect on radial growth of drought-stressed trees. Forest management should be based on the different adaptation strategies of larch to climatic stresses in heterogeneous environments.

随着气候变化，干湿事件的频率和强度都在增加，其对树木生长影响的不确定性也在增加。目前已有关于干湿条件对树木生长影响的研究，但缺乏在异质环境中树木对不同类型干湿事件适应策略的比较。因此，我们利用中亚阿尔泰山脉（西部）和蒙古高原（东部）西伯利亚落叶松（Larix sibirica）的树环宽度数据，探讨了树木径向生长对不同类型干湿事件反应的差异。结果表明，西部树木的径向生长与降水量和标准化降水蒸散指数（SPEI）呈显著负相关，与平均气温呈显著正相关。东部树木的径向生长与降水量和标准降水蒸散指数呈显著正相关，与平均气温呈显著负相关。湿胁迫地区的树木对复合冷湿事件的抵抗力低于普通湿事件。干旱胁迫地区的树木对复合热干旱事件的抵抗力低于普通干旱事件。湿胁迫地区的树木在普通湿润事件和复合冷湿事件后的第一年都能恢复到正常生长水平，而旱胁迫地区的树木在普通干旱事件和复合热干旱事件后都未能恢复，但随后出现了补偿性生长。因此，气候变暖对湿胁迫地区树木的径向生长有积极影响，而对干旱胁迫地区树木的径向生长有消极影响。森林管理应以落叶松在不同环境下对气候胁迫的不同适应策略为基础。

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引用次数: 0

Chronology, structures and salt tectonics in the northern Kuqa Depression, NW China: Implications for the Cenozoic uplift of Tian Shan and foreland deformation 中国西北部库车凹陷北部的年代学、构造和盐构造：对新生代天山隆升和前陆变形的影响

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-03 DOI: 10.1016/j.gloplacha.2024.104618

Zhiliang Zhang , Pengcheng Tang , Jimin Sun , Zhikun Ren

Foreland fold-and-thrust belts (FTBs) are shaped by the coupled influence of surface processes (e.g., erosion, sedimentation) and deep geological processes (e.g., plate rheology, flexure and kinematics) across various timescales. These processes record multiple phases of orogenic evolution and are crucial for understanding the interplay between mountain building and the sedimentary basin filling. In this paper, we conducted an integrated study including magnetostratigraphy of exposed strata, detailed field investigations and interpretations of subsurface seismic profiles in the northern Kuqa Depression. This study aims to elucidate the tectonic uplift of the Tian Shan by examining salt-related structures. The present findings reveal that diapirism in the study area commenced in the early Eocene and continued at least into the late Miocene. Notably, the Tuzimaza diapir has been significantly squeezed due to regional contraction since ∼5.3 Ma. The exposed growth strata were primarily compressional, rather than halokinetic, suggesting the lateral expansion of the Tuzimaza anticline since the latest Miocene (∼5.3 Ma). This expansion was a response to the far-field effects of the Indian-Eurasian collision. We propose that the local activation of the Tian Shan likely initiated in the early Oligocene (∼34 Ma), with three subsequent episodes of deformation occurring ∼24 Ma, ∼10 Ma and ∼ 5.3 Ma. The earlier episodes can be attributed to basement uplift in the northern Kuqa Depression, whereas the later episode starting at ∼5.3 Ma reflects more intensive deformation across the entire foreland, indicative of the steady outward growth of the Tian Shan. Collectively, all these tectonic events have contributed to the formation of the modern Tian Shan.

地表过程（如侵蚀、沉积）和深部地质过程（如板块流变、挠曲和运动学）在不同时间尺度上的耦合影响塑造了前陆褶皱和推力带。这些过程记录了造山演化的多个阶段，对于理解造山运动与沉积盆地填充之间的相互作用至关重要。在本文中，我们在库卡凹陷北部进行了一项综合研究，包括出露地层的磁地层学、详细的实地调查和地下地震剖面解释。这项研究旨在通过考察与盐有关的构造来阐明天山的构造隆升。目前的研究结果表明，研究地区的断裂活动始于始新世早期，至少持续到中新世晚期。值得注意的是，自∼5.3Ma以来，图齐玛扎断裂带由于区域收缩而受到严重挤压。出露的生长地层主要是压缩性地层，而不是卤化性地层，这表明图齐马扎反斜坡自中新世晚期（5.3Ma∼）以来发生了横向扩张。这种扩张是对印度-欧亚碰撞远场效应的反应。我们认为，天山的局部活化可能始于渐新世早期（34 Ma），随后的三次变形分别发生在24 Ma、10 Ma和5.3 Ma。早期的变形可归因于库车坳陷北部的基底隆起，而始于 5.3 Ma 的后期变形则反映了整个前陆更密集的变形，表明天山在稳步向外发展。所有这些构造事件共同促成了现代天山的形成。

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引用次数: 0

The history of the El Niño–Southern Oscillation and sea surface salinity during 1376–1500 CE reconstructed by Porites coral δ18O from Huangyan Island, South China Sea 南海黄岩岛海泡石珊瑚δ18O重建的厄尔尼诺-南方涛动和公元1376-1500年期间海表盐度的历史

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-03 DOI: 10.1016/j.gloplacha.2024.104622

Shichen Tao , Kam-biu Liu , Hongqiang Yan , Min Meng , Kefu Yu , Qi Shi , Huiling Zhang

The El Niño–Southern Oscillation (ENSO) is the most influential climatic phenomenon affecting global ecosystems, water use, and agriculture on an interannual scale. However, limited instrumental records make it difficult to fully understand the characteristics of ENSO events. In this study, we used both monthly-resolved Porites coral δ¹⁸O records, i.e., living Porites corals of δ¹⁸O–HYDL4 (1992–2015) and subfossil Porites corals of δ¹⁸O–HYD3 (1376–1500 CE), from Huangyan Island in the South China Sea (SCS), to reconstruct the moderate intensity ENSO and sea surface salinity (SSS) during 1376–1500 CE. The results show that the SSS was higher but the frequency of moderate-to-high intensity ENSO events was lower than the present during 1376–1500 CE. ENSO activity was generally similar to or slightly lower than that of today, but it included several very strong ENSO events in the first substage (1376–1450 CE), while it was relatively quiet in the second substage (1451–1500 CE). More moderate-intensity ENSO events may have occurred in the relatively warm climate. The variation in coral δ¹⁸O was dominated by multiple factors in this region. SST, ENSO and the Pacific Decadal Oscillation (PDO) may be the dominant factors influencing the changes in coral δ¹⁸O at different timescales.

厄尔尼诺-南方涛动（ENSO）是影响全球生态系统、水资源利用和农业年际尺度的最有影响力的气候现象。然而，由于仪器记录有限，很难全面了解 ENSO 事件的特征。在本研究中，我们利用南海黄岩岛的月分辨波罗的海珊瑚δ18O记录，即活体波罗的海珊瑚δ18O-HYDL4（1992-2015年）和亚化石波罗的海珊瑚δ18O-HYD3（公元1376-1500年），重建了公元1376-1500年期间中等强度的ENSO和海表盐度（SSS）。结果表明，公元 1376-1500 年期间，SSS 较高，但中高强度 ENSO 事件的频率比现在低。厄尔尼诺/南方涛动活动总体上与现在相似或略低于现在，但在第一子阶段（西元 1376-1450 年）包括几次非常强烈的厄尔尼诺/南方涛动事件，而在第二子阶段（西元 1451-1500 年）则相对平静。在相对温暖的气候条件下，可能发生了更多强度适中的厄尔尼诺/南方涛动事件。该地区珊瑚 δ18O 的变化受多种因素的影响。在不同时间尺度上，海温、厄尔尼诺/南方涛动和太平洋十年涛动可能是影响珊瑚 δ18O 变化的主要因素。

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引用次数: 0

Erosion modulates the effect of chemical weathering on atmospheric pCO2, Qinghai-Tibet Plateau 青藏高原侵蚀调节化学风化作用对大气 pCO2 的影响

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-11-01 DOI: 10.1016/j.gloplacha.2024.104619

Heping Lu , Han Luo , Jun Zhong , Sen Xu , Tingting Ma , Si-Liang Li

Chemical weathering plays an important role in modulating Earth's climate. However, chemical weathering is usually influenced by multiple factors simultaneously (e.g., climate, topography and lithology), and it is difficult to understand how these variables modulate the effect of chemical weathering on atmospheric pCO₂. In this study, we collected and analyzed water chemistry and multiple isotopes (δ³⁴S_SO4, δ¹⁸O_SO4 and δ¹⁸O_H2O) in the Bailong River catchment to decipher how these variables influence chemical weathering and its effect on atmospheric pCO₂. We used the Monte Carlo inversion model to partition the sources of major cations and

{SO}_{4}^{2 -}

, and the results reveal that carbonate weathering is the dominant source contributing cations in river. Sulfide oxidation is the most important source for

{SO}_{4}^{2 -}

and a supply-limited process that is highly dependent on slope. We thus think slope is main factor modulating the effect of chemical weathering on atmospheric pCO₂. Steep slope increases sulfide oxidation rate by elevating erosion, resulting in chemical weathering acting as a CO₂ source. In contrast, gentle slope could facilitate a thick regolith that contributes long-term silicate weathering and limits sulfide oxidation, resulting in chemical weathering acting as a CO₂ sink. And it has been found that the influence of temperature on chemical weathering becomes progressively pronounced with increasing altitude. This study investigated sulfide weathering in eroding Qinghai-Tibet Plateau, highlighting the geomorphologically controlled CO₂ effects of chemical weathering.

化学风化作用在调节地球气候方面发挥着重要作用。然而，化学风化作用通常同时受到多种因素（如气候、地形和岩性）的影响，因此很难了解这些变量如何调节化学风化作用对大气 pCO2 的影响。在本研究中，我们收集并分析了白龙江流域的水化学和多种同位素（δ34SSO4、δ18OSO4 和 δ18OH2O），以解读这些变量如何影响化学风化作用及其对大气 pCO2 的影响。我们利用蒙特卡罗反演模型对主要阳离子和 SO42- 的来源进行了划分，结果表明碳酸盐风化是河流中阳离子的主要来源。硫化物氧化是 SO42- 的最重要来源，也是一个与坡度高度相关的供应受限过程。因此，我们认为坡度是调节化学风化对大气 pCO2 影响的主要因素。陡坡通过提高侵蚀作用增加硫化物的氧化率，导致化学风化作用成为二氧化碳的来源。与此相反，缓坡有利于形成厚厚的沉积岩，从而促进硅酸盐的长期风化，限制硫化物的氧化，使化学风化成为二氧化碳的吸收汇。研究还发现，温度对化学风化的影响随着海拔的升高而逐渐明显。本研究对青藏高原侵蚀作用下的硫化物风化作用进行了研究，突出了化学风化作用受地貌控制的二氧化碳效应。

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引用次数: 0

1.6 Ma biostratigraphy, oxygen isotope record and paleoceanography of the IODP 353 Site U1443 in the equatorial eastern Indian Ocean 赤道东印度洋 IODP 353 站点 U1443 的 1.6 Ma 生物地层学、氧同位素记录和古海洋学

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-10-29 DOI: 10.1016/j.gloplacha.2024.104617

Molin Wang , Xuan Ding , Liping Zhou

Paleoceanographic studies rely heavily on an accurate stratigraphy as well as the interpretation of the oxygen isotope (δ¹⁸O) records generated from microfossils. In this study, we present new planktonic foraminiferal assemblage and stable oxygen isotope records of both planktonic and benthic foraminifera from sedimentary deposits at the IODP Site U1443 on the northern Ninety East Ridge in the equatorial eastern Indian Ocean. Five planktonic foraminiferal datums were identified, which allowed us to refine the Pleistocene biostratigraphical sequence of the site. Our benthic δ¹⁸O record was tuned to that of the LR04 stack with consideration of the planktonic foraminifera and nannofossil datums, volcanic ash, and geomagnetic reversal events. This led to a refined stratigraphic framework for 1.6 Ma at the IODP Site U1443. We focus our discussion on the paleoceanographic and paleoclimatic interpretations of the newly obtained δ¹⁸O records. The synchronous variations of the U1443 planktonic δ¹⁸O record with the obliquity fluctuations during the 1.6 Ma – 0.8 Ma point to the presence of a signal of high-latitude insolation in the surface waters of the study area. By contrast, from 0.8 Ma, the δ¹⁸O record exhibits distinct precession signal, as observed in the South China Sea, which we interpret as being influenced by regional hydroclimate dynamics, such as monsoons. This study therefore provides new data for investigating possible mechanisms that link the high and low latitudes into the early Pleistocene.

古海洋学研究在很大程度上依赖于准确的地层学以及对微小化石生成的氧同位素（δ18O）记录的解释。在本研究中，我们展示了赤道东印度洋九十东海脊北部 IODP U1443 号站点沉积物中浮游有孔虫和底栖有孔虫的新浮游有孔虫组合和稳定氧同位素记录。我们确定了五个浮游有孔虫标本，从而完善了该地点的更新世生物地层序列。考虑到浮游有孔虫和化石基准、火山灰和地磁反转事件，我们将底栖生物的δ18O记录调整为 LR04 叠层的记录。这样，IODP U1443地点的1.6 Ma地层框架就得到了完善。我们重点讨论了新获得的δ18O记录对古海洋学和古气候的解释。U1443 浮游生物 δ18O 记录与 1.6 Ma - 0.8 Ma 期间纬度波动的同步变化表明研究区表层水域存在高纬度日照信号。相比之下，从 0.8 Ma 开始，δ18O 记录显示出明显的前向信号，正如在中国南海所观察到的那样，我们将其解释为受到季风等区域水文气候动态的影响。因此，这项研究为研究将高纬度和低纬度联系到早更新世的可能机制提供了新的数据。

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引用次数: 0

Topography alters the optimum timing of peatland initiation across Northeast China during the Holocene 地形改变了全新世中国东北地区泥炭地形成的最佳时机

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-10-28 DOI: 10.1016/j.gloplacha.2024.104616

Yakun Chen , Zicheng Yu , Lei Xu , Guoping Wang , Jinxin Cong , Dongxue Han , Chuanyu Gao

Peatlands are a key carbon sink and play an important role in the global carbon cycle and climate change. Understanding the process of peatland initiation is essential to understand the carbon sink functions of peatlands. While the climate is widely recognized as the main driver that controls the peatland initiation, the importance of topography, a limiting factor that influencing local climate conditions, is still unclear. Here, we used data from 231 peatlands in Northeast China to evaluate the role of topography on peatland initiation. The results show that most peatlands that initiated during the Late Holocene was distributed at elevations <200 m (51 % of sites) and slopes <5° (44 % of sites). The optimum timing of peatland initiation is delayed with increasing elevation and slope, and the potential reasons we speculated is that the increasing elevation slows vegetation growth owing to the decrease in temperature. In addition, steeper slopes are not conducive of water retention. There was little effects of slope aspect on peatland initiation, most likely because variations in solar radiation under various slope aspects may not have a substantial impact on local environmental factors. This study demonstrates that elevation and slope are more important than slope aspect on the frequency and optimum timing of peatlands initiation in Northeast China during the Holocene.

泥炭地是一种关键的碳汇，在全球碳循环和气候变化中发挥着重要作用。了解泥炭地的形成过程对于理解泥炭地的碳汇功能至关重要。虽然人们普遍认为气候是控制泥炭地形成的主要因素，但地形这一影响当地气候条件的限制因素的重要性仍不明确。在此，我们利用中国东北地区 231 块泥炭地的数据评估了地形对泥炭地形成的作用。结果表明，晚全新世期间形成的泥炭地大多分布在海拔200米（51%的地点）和坡度5°（44%的地点）的地区。泥炭地形成的最佳时机随着海拔和坡度的增加而推迟，我们推测其潜在原因是，海拔的增加导致温度降低，从而减缓了植被的生长。此外，较陡的斜坡不利于水分保持。坡度对泥炭地形成的影响很小，这很可能是因为不同坡度下太阳辐射的变化对当地环境因素的影响不大。本研究表明，对于全新世期间中国东北地区泥炭地形成的频率和最佳时间而言，海拔和坡度比坡度更为重要。

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引用次数: 0

Satellite detection of sea fog and low clouds in the Arctic in the daytime during the summer through multiple sources of infrared remote sensing 通过多种红外遥感来源对夏季白天北极海雾和低云进行卫星探测

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-10-28 DOI: 10.1016/j.gloplacha.2024.104615

Huiyun Ma , Zengwei Liu , Yinze Ran , Xiaojing Wu , Huihui Feng

A greater frequency of sea fog/low clouds may be observed in the Arctic under the effects of global warming, which strongly affects the safety of navigation in the Arctic. Using moderate-resolution imaging spectroradiometer (MODIS) infrared multiband remote sensing data, in this paper, we construct a detection algorithm for sea fog and low clouds in the daytime during the summer period in the Arctic through multiband infrared remote sensing. Physically, the algorithm relies on the spectral variation in the Arctic Sea route region with different solar zenith angles (SZAs). Specifically, for days with strong sunshine (SZA < 70°), the effect of the sea surface is removed by coupling the B7 (2.130 μm) near-infrared band reflectance (R_{2.130 μm}) and the radiation difference (BTD_{3.750 μm}_–_{11.030 μm}) between the B20 (3.750 μm) mid-infrared band (BT_{3.750 μm}) and B31 (11.030 μm) thermal infrared band (BT_{11.030 μm}). Then, the sea fog and low-cloud ratio index (SFLCRI) is constructed on the basis of two near-infrared bands, namely, the B5 (1.240 μm) water vapor absorption band and the B9 (0.936 μm) atmosphere window, to remove the middle and high clouds. Finally, the sea fog and low clouds are extracted according to the radiation threshold of BT_{11.030 μm}. At dawn and dusk (SZA > 70°), the SFLCRI is utilized to remove the sea surface and middle and high clouds, and then the undetected middle and high clouds are removed via BT_{11.030 μm}. The validation results reveal that the accuracy of the algorithm is high, and the probability of detection, false alarm ratio, and the critical success index of sea fog and low-cloud detection are 86 %, 13 %, and 76 %, respectively, as a whole. The algorithm accuracy was less affected by time. The research results are of great theoretical and practical importance for Arctic sea fog and low-cloud detection, and for ensuring the safety of Arctic shipping.

在全球变暖的影响下，北极地区可能会更频繁地出现海雾/低云，这严重影响了北极地区的航行安全。本文利用中分辨率成像分光仪（MODIS）红外多波段遥感数据，通过多波段红外遥感构建了北极夏季白天海雾和低云的探测算法。从物理上讲，该算法依赖于不同太阳天顶角（SZA）下北极海路区域的光谱变化。具体来说，在日照强烈的日子（SZA < 70°），通过耦合 B7（2.130 μm）近红外波段反射率（R2.130 μm）和 B20（3.750 μm）中红外波段（BT3.750 μm）与 B31（11.030 μm）热红外波段（BT11.030 μm）之间的辐射差（BTD3.750 μm-11.030 μm）来消除海面的影响。然后，根据两个近红外波段，即 B5（1.240 μm）水汽吸收波段和 B9（0.936 μm）大气窗口，构建海雾和低云比例指数（SFLCRI），以去除中云和高云。最后，根据 BT11.030 μm 的辐射阈值提取海雾和低云。在黎明和黄昏（SZA > 70°），利用 SFLCRI 去除海面和中高云，然后通过 BT11.030 μm 去除未检测到的中高云。验证结果表明，该算法的准确率较高，海雾和低云的整体检测概率、误报率和临界成功指数分别为 86%、13% 和 76%。算法精度受时间影响较小。该研究成果对北极海雾和低云检测、保障北极航运安全具有重要的理论和实践意义。

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引用次数: 0

Diverse glacial ventilation in deep Pacific: An integrated record from Mariana Trench and Magellan Seamounts over the last 1.2 Myr [Global and Planetary Change, volume 230, November 2023, 104279]: Comment 太平洋深处多样的冰川通风：马里亚纳海沟和麦哲伦海山过去 1.2 Myr 的综合记录[《全球和行星变化》，第 230 卷，2023 年 11 月，104279]：评论

IF 4 1区地球科学 Q1 GEOGRAPHY, PHYSICAL

Global and Planetary Change

Pub Date : 2024-10-24 DOI: 10.1016/j.gloplacha.2024.104614

Yang Wang , Tongzheng Zhang , Harunur Rashid

Yi (2023) proposed a new deep Western Pacific ventilation hypothesis using beryllium (¹⁰Be/⁹Be) and ²³⁰Th_ex dates, magnetostratigraphy, and element-based tuning data from two box cores and one gravity core. However, given the low sedimentation rates of these cores and uncertain stratigraphy, we suggest that some interpretations require further clarifications and corrections. The low sedimentation rates cast doubt on the validity of the millennial-scale western Pacific bottom-water oxygenation variability. The lack of unsupported explanations about the newly found periodicity in the Mariana Trench and Magellan Seamounts records raises concern about the confidence of the age models. The phasing between the North Atlantic deep water and Antarctic bottom water formation and atmospheric pCO₂ in the deep Western Pacific setting is unclear.

Yi（2023 年）利用铍（10Be/9Be）和 230Thex 年代、磁地层学以及来自两个箱形岩心和一个重力岩心的基于元素的调谐数据，提出了一个新的西太平洋深层通风假说。然而，鉴于这些岩心的沉积速率较低，地层不确定，我们认为某些解释需要进一步澄清和修正。低沉积速率使人对千年尺度的西太平洋底层水含氧量变化的有效性产生怀疑。对马里亚纳海沟和麦哲伦海山记录中新发现的周期性缺乏支持性解释，使人对年龄模型的可信度产生担忧。北大西洋深层水和南极底层水的形成与西太平洋深层环境中大气 pCO2 之间的相位关系尚不清楚。

引用次数: 0