Global and Planetary Change最新文献

{"title":"Skill of isotope-enabled climate models for daily surface water vapour in East Asia","authors":"Shengjie Wang ,&nbsp;Yuqing Qian ,&nbsp;Kei Yoshimura ,&nbsp;Hayoung Bong ,&nbsp;Camille Risi ,&nbsp;Zhongwang Wei ,&nbsp;Hongxi Pang ,&nbsp;Wei Xiao ,&nbsp;Shijun Lei ,&nbsp;Meng Xing ,&nbsp;Pei Zhao ,&nbsp;Huawu Wu ,&nbsp;Yudong Shi ,&nbsp;Di Wang ,&nbsp;Mingjun Zhang","doi":"10.1016/j.gloplacha.2024.104502","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104502","url":null,"abstract":"<div><p>The isotope-enabled general circulation models (GCM) have been widely applied to simulate the variability of stable isotopes in meteoric water at various time scales. The in-situ observations of water vapour isotopes are an important basis for assessing the performance of isotope-enabled GCMs, although they are still limited. Here we compiled the observations of near-surface water vapour isotopes on a daily scale at 17 stations in East Asia, and assessed the skill and the association between isotope error and meteorological errors on a daily scale. Generally, the spatial pattern and seasonal variability can be well simulated in the isotope-enabled GCMs. The models show better skill for warm and humid backgrounds, which also corresponds to the monsoonal regions with lower latitudes in East Asia. As spatial resolution is finer, the skill of models is better, which can be seen from the two GCMs. According to the correlation coefficient, the improvement of resolution is more obvious in summer than in winter, especially for IsoGSM. In addition, the correlation coefficient in winter is usually larger than that in summer. The daily modelling has good potential to investigate the daily or synoptic climate information in water isotopes. The findings are useful for understanding the applicability of isotope-enabled models in East Asia and the climate factors influencing the skill of isotope-enabled models on a daily basis.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extremely 26Mg-enriched authigenic clays from the Ediacaran Doushantuo Formation (South China) indicating the coupled carbonate-silicate diagenesis","authors":"Tianzheng Huang ,&nbsp;Bing Shen ,&nbsp;Xiaoli Wang ,&nbsp;Haoran Ma ,&nbsp;Chao Li ,&nbsp;Chuanming Zhou","doi":"10.1016/j.gloplacha.2024.104500","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104500","url":null,"abstract":"<div><p>In the aftermath of Marinoan global glaciation (∼650–635 Ma), the deglacial intense continental weathering tended to dramatically lower the atmospheric pCO₂ level, potentially driving the Earth back to the glacial climatic condition. However, the resultant global cooling and glaciation did not occur. The CO₂ drawdown by continental weathering might have been compensated by additional CO₂ release via reverse weathering in the ocean, as evidenced by abundant precipitations of authigenic clay minerals, for example, Mg-rich saponite and clinochlore in the lower part of Doushantuo Formation (635–551 Ma) in South China. Massive precipitations of Mg-rich authigenic clays imply a distinct marine Mg cycle in the early Ediacaran ocean, but their origins have been debated. Here, we measured the Mg isotopic compositions of authigenic clays from the Doushantuo Formation. Both saponite and clinochlore are extremely ²⁶Mg-enriched, with Mg isotopes of saponite (δ²⁶Mg_sap) up to +0.39‰ and clinochlore up to +1.26‰. Considering the Mg isotopic fractionation in saponite precipitation ranging from −0.95‰ to −1.45‰, high δ²⁶Mg_sap values requires extremely high seawater Mg isotopic composition (δ²⁶Mg_sw), which cannot be resolved by direct precipitation with seawater Mg supply. Instead, it requires other diagenetic processes that elevated the porewater Mg isotopic composition (δ²⁶Mg_pw). A numerical model was applied to quantify the Mg isotopic fractionation in diagenesis. The modeling result indicates an earlier dolomitization relative to saponite precipitation might have elevated the porewater Mg isotopes, followed by the precipitation of extremely ²⁶Mg-enriched saponite. The coupled carbonate-silicate diagenesis is a key mechanism sustaining stable seawater Mg concentration and δ²⁶Mg, highlighting authigenic clay mineral as a buffer for Mg and C cycles counterbalancing massive weathering input after Marinoan glaciation.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precipitation mechanism of Mn ore deposits in the Datangpo Formation, Nanhua Basin, South China","authors":"Hua Chen ,&nbsp;Haifeng Fan ,&nbsp;Danish Khan ,&nbsp;Xi Jiang ,&nbsp;Lianjun Feng ,&nbsp;Hanjie Wen ,&nbsp;Huanhuan Tian ,&nbsp;Xiangkun Zhu","doi":"10.1016/j.gloplacha.2024.104499","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104499","url":null,"abstract":"<div><p>During the interglacial period of the Cryogenian glaciation, the extensive “Datangpo-type” manganese ores were deposited in the Nanhua Basin. However, there has been significant controversy over the precipitation mechanism of manganese for decades. Based on iron and nitrogen isotope data from the manganese ores of the Datangpo Formation in Chongqing (South China), combined with previous research, we propose that the manganese ores of the Datangpo Formation precipitated directly in an anoxic bottom-water environment in the form of rhodochrosite. The δ⁵⁶Fe values in the Bijiashan manganese ore (δ⁵⁶Fe = −0.19 ± 0.13 ‰) are close to those of modern marine hydrothermal iron, and there is a strong positive correlation between the δ⁵⁶Fe value and iron concentration (R² = 0.81), indicating that the precipitation of manganese ore could be mainly affected by hydrothermal input. After comprehensively comparing the δ⁵⁶Fe values of the whole rock and pyrite in the manganese ore of the Datangpo Formation, we believe that iron from hydrothermal sources directly and quantitatively combined with sulfides to form pyrite. Additionally, the bottom seawater of the basin was mainly anoxic. The nitrogen isotope composition indicates the presence of a stable nitrate reservoir in the ocean at that time, and manganese ore deposition may have been influenced by the input of high-salinity water from the open ocean. Due to the supply of NO₃^- from the open ocean to the graben basin, the δ¹⁵N in manganese ore is significantly higher than that in black shale. The input from the open ocean led to an increase in alkalinity in the bottom water of the basin, which favored the precipitation of rhodochrosite. Considering that the oxidation potential required for manganese oxidation precipitation is higher than that required for iron oxidation precipitation, it is most reasonable to conclude that under alkaline anoxic conditions in the bottom water layer, Mn²⁺ directly precipitated in the form of rhodochrosite.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultraselective enrichment of trace elements in seawater by Co-rich ferromanganese nodules","authors":"Jiangbo Ren ,&nbsp;Gaowen He ,&nbsp;Yong Yang ,&nbsp;Miao Yu ,&nbsp;Yinan Deng ,&nbsp;Yuntian Pang ,&nbsp;Bin Zhao ,&nbsp;Huiqiang Yao","doi":"10.1016/j.gloplacha.2024.104498","DOIUrl":"10.1016/j.gloplacha.2024.104498","url":null,"abstract":"<div><p>Ferromanganese nodules are huge metal resources and windows into Earth processes, being widely distributed in vast deep-sea basins covered by sediments. Co-rich ferromanganese nodules are typical hydrogenetic deposits that can effectively scavenge and enrich multiple trace elements in seawater. However, uncertainty still exists regarding the enrichment process of hydrogenetic nodules and their interactions with the distribution of trace elements in seawater. Herein, we analyzed up to 73 elements in Co-rich ferromanganese nodules from the western Pacific and found that high-field strength and redox-sensitive elements are selectively distributed between the Fe and Mn hydroxide phases. These elements are highly enriched in ferromanganese nodules over seawater and upper continental crustal values. The enormous amounts of ferromanganese deposits make them the major, even exclusive, budget for Te, Mn, Co, Ce, Pb, Bi, Pt, Ru, Rh, Ni, and Mo. The distributions of trace elements in seawater are both the cause and result of scavenging by ferromanganese deposits and of biogeochemical cycling. In particular, ferromanganese deposition is responsible for the distributions of scavenged-type elements such as Mn, Co, Ce, Pb, Bi, and Te in seawater. Based on the distributions of elements in seawater and at the water–sediment interface, we propose a new two-stage model for nodule metallogenesis. Stage I is the initial enrichment of trace elements by the sinking of ferromanganese hydroxide colloids, which regulate the distributions of scavenged-type elements in the water column. Stage II is the top-down migration of trace elements dominated by bioparticle cycling, which promotes the re-enrichment of trace elements by ferromanganese hydroxides at the water–sediment interface.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0921818124001450/pdfft?md5=96d7a8bd4d7534edf7b135258823b94e&pid=1-s2.0-S0921818124001450-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle size shapes prokaryotic communities and vertical connectivity in the water columns of the slope and central basin of the South China Sea","authors":"Zhonglin Ma ,&nbsp;Paraskevi Mara ,&nbsp;Lei Su ,&nbsp;Long Wang ,&nbsp;Huifang Li ,&nbsp;Rui Zhang ,&nbsp;Virginia P. Edgcomb ,&nbsp;Jiangtao Li","doi":"10.1016/j.gloplacha.2024.104497","DOIUrl":"10.1016/j.gloplacha.2024.104497","url":null,"abstract":"<div><p>Sinking of organic matter represents an essential mechanism for sequestration of carbon that is exported from the ocean surface to deeper depths. While recent studies have highlighted the important role of microorganisms in the biological pump, the impact of sinking particles on the vertical connectivity of microbial communities has received limited attention. In this study, we present the microbial profile of sinking particles in the northern slope and the central basin of the marginal South China Sea (SCS) using an in-line size-fractionated water filtration and Illumina high-throughput 16S rRNA amplicon sequencing. We investigate the microbial community composition within organic particles of different size fractions (30, 5, 3, 0.22 μm), and we reveal significant differences in the microbial community structure between these two distinct areas of SCS. The vertical connectivity of microbial communities in the slope and the central basin of SCS shows distinct patterns of microbial dispersal along the water column that occurs via the sinking of organic particles. We find that the microbial communities have different abundances on the different examined particle size fractions and which highlights the role of sinking particles in shaping microbial lifestyles along the water column. Our study underscores the influence of environmental variations on the vertical connectivity of microorganisms and provides additional insights into the marine biological pump under different environmental conditions.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":4.0,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial preface to special issue: Cenozoic climate change in Asia in honour of Prof. Zhengtang Guo","authors":"Chenglong Deng ,&nbsp;Zhongshi Zhang ,&nbsp;Qiuzhen Yin","doi":"10.1016/j.gloplacha.2024.104496","DOIUrl":"10.1016/j.gloplacha.2024.104496","url":null,"abstract":"<div><p>The Asian monsoon has progressively become a megamonsoon system since the early Cenozoic. To improve our understanding of the complex nature of the Asian monsoon system, involving strong interactions between atmospheric, oceanic and terrestrial systems across different timescales, we present this special issue, entitled <em>Cenozoic climate change in Asia</em>. The special issue is dedicated to Prof. Zhengtang Guo in honour of his distinguished contributions as Editor-in-Chief of <em>Global and Planetary Change</em> to our understanding of the long-term evolution of the Asian monsoon system. The special issue consists of nineteen papers, grouped into three categories, that address Cenozoic climate change, mainly in Asia. The first category focuses on the plate tectonic-scale and considers how changes in palaeogeography and palaeotopography have shaped climate evolution. The second category addresses orbital- to suborbital-scale climate change and, in particular, explores the links between low-latitude insolation, high-latitude ice sheets and the Asian climate. The third category addresses millennial- to decadal-scale climate changes. In addition, past human-environment interactions are also discussed. These studies provide important insights into our understanding and prediction of both natural variability and human-induced climate changes in Asia and their linkages with global climate within the Earth System.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141397579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Past and future joint return period of precipitation extremes over South Asia and Southeast Asia","authors":"V.M. Reddy,&nbsp;Litan Kumar Ray","doi":"10.1016/j.gloplacha.2024.104495","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104495","url":null,"abstract":"<div><p>Climate change is one of the major reasons for the increased intensity and frequency of precipitation extremes in tropical regions. This will have a significant impact on underdeveloped countries in South Asia and Southeast Asia. Therefore, this study analyzes changes in spatiotemporal patterns and the joint behavior of precipitation extremes across South Asian and Southeast Asian countries for the historical period (1975 to 2014) and future periods (2021–2060 (F1) and 2061–2100 (F2)). This study develops bias-corrected precipitation data and ranks General Circulation Models (GCMs) using the Empirical Quantile Mapping method and TOPSIS method, respectively. A multi-model ensemble of precipitation extremes is created using the top five GCMs. The Mann Kendall test is used to analyze trends in precipitation extremes. Joint probabilistic analysis is also conducted for different combinations of ETCCDI precipitation-based indices using Archimedes and Elliptical copulas. The results of the trend analysis indicate significant positive trends for R20mm (19.26%), R95pTOT (18.40%), Rx5Day (11.53%), and CWD (10.46%), while CDD (5.07%) shows a significant negative trend across the study area during historical period (1975–2014). The results of R20mm, R95pTOT, and Rx5Day under SSP585 shows almost 19 to 39% of area comes under significant positive trend during the F1 period. This becomes more evident in F2, with trends under SSP585 rising between 32% and 61%. The high-emissions scenario SSP585 reveals an increase in these positive trends compared to SSP126 in both the future periods (F1 and F2). These results indicating a noticeable rise in extreme precipitation events. The analysis of changes in the joint return period of precipitation extremes indicates that the South Peninsular India, North East India, West Central India and Central Northeast India, as well as most parts of Southeast Asian countries, will experience very heavy intensify precipitations in the future. In addition, persistent co-occurrence of dry and wet conditions will be observed in Pakistan, North West India, and Central Northeast India. This study provides useful information on the distribution of precipitation extremes in different regions of the study area.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141324551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Marine sulfate sulfur isotopic evidence for enhanced terrestrial weathering and expansion of oceanic anoxia during the Devonian-Carboniferous transition","authors":"Jiangsi Liu ,&nbsp;Genming Luo ,&nbsp;Thomas J. Algeo ,&nbsp;Wenkun Qie ,&nbsp;Le Yao ,&nbsp;Junhua Huang ,&nbsp;Shucheng Xie","doi":"10.1016/j.gloplacha.2024.104494","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104494","url":null,"abstract":"<div><p>The Hangenberg mass extinction during the Devonian-Carboniferous (D-C) transition represents one of the largest biodiversity losses of the Phanerozoic, while the underlying cause remains controversial. An improved understanding of the contemporaneous sulfur cycle can provide insights into the latest Devonian environmental changes that potentially affected marine biotas. Here, we report on a high-resolution chemostratigraphic study of the sulfur isotopic composition of carbonate-associated sulfate (CAS) through the D-C transition in the Long'an and Qilinzhai sections of South China. The δ³⁴S_CAS profiles exhibit a long-term (i.e., &gt;10⁵ yr) negative excursion from +19.0‰ in the upper Lower <em>Si. praesulcata</em> Zone to +13.0‰ in the middle Upper <em>Si. praesulcata</em> Zone, and terminated with a recovery to 20.3‰ in the lower <em>Si. sulcata</em> – <em>Si. duplicata</em> zones, representing a depositional interval of ∼0.9 Myr. In addition, this long-term negative excursion is punctuated by episodic sharp negative shifts. The negative δ³⁴S_CAS excursion coincided with the end-Devonian biotic crisis, a positive shift in carbonate δ¹³C, and negative shifts in bulk-sediment δ¹⁵N values and I/Ca ratios. Increasing organic carbon burial indicated by the positive shift in δ¹³C precludes decreased pyrite burial as an explanation for the negative shift of δ³⁴S_CAS, supported by intensified marine anoxia revealed by the negative shifts in δ¹⁵N and I/Ca. We attribute the long-term negative shift in δ³⁴S_CAS to enhanced inputs of ³⁴S-depleted riverine sulfate in conjunction with low seawater sulfate concentrations within the semi-restricted Yangtze Sea, whereas the transient negative spikes in δ³⁴S_CAS were possibly caused by episodic upwelling and oxidation of H₂S in expanded oceanic oxygen-minimum zones. In conjunction with the positive shift in δ¹³C, the negative shift in δ³⁴S_CAS supports a significant role for enhanced subaerial weathering in intensifying marine anoxia and triggering the biotic crises that occurred during the latest Devonian, the most likely driver of which was the spread of vascular (especially seed-bearing) land plants.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141314769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in pCO2 and climate paced by grand orbital cycles in the late Cenozoic","authors":"Yifei Zhang ,&nbsp;Qiang Fang ,&nbsp;Huaichun Wu ,&nbsp;Christian Zeeden ,&nbsp;Ying Cui ,&nbsp;Meinan Shi ,&nbsp;Shihong Zhang ,&nbsp;Tianshui Yang ,&nbsp;Haiyan Li","doi":"10.1016/j.gloplacha.2024.104493","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104493","url":null,"abstract":"<div><p>As one of the most important greenhouse gases, CO₂ is considered a major controlling factor of Earth's climate over geological timescales. However, the origins of quasi-periodic fluctuations in <em>p</em>CO₂ on a million-year timescale remain unclear. Here, we used published datasets of atmospheric <em>p</em>CO₂, oxygen isotopes of benthic foraminifera (δ¹⁸O_benthic) and global mean sea-level (GMSL) from 23 Ma to the present to explore the pacing of <em>p</em>CO₂ changes and concomitant climatic effects using multiple time series analysis approaches. Our results indicate that the evolution of late Cenozoic <em>p</em>CO₂ and climate was paced by the grand orbital cycles, in particular the ~4.5 Myr and ~ 2.4 Myr eccentricity cycles, and ~ 1.3 Myr obliquity cycle. Periodic occurrence of cold conditions was associated with low climate seasonality during the minima of ~4.5 Myr and ~ 2.4 Myr eccentricity cycles. We suggest that cooler conditions are associated with decreased atmospheric <em>p</em>CO₂ as a result of higher organic carbon burial due to lower metabolic rate of heterotrophic bacteria and more organic carbon export to the deep ocean. Furthermore, the buildup of glaciers during the minima of grand eccentricity cycles might lower <em>p</em>CO₂ via increased ice cover and enhanced dust fluxes. In contrast, high seasonal climate may lead to an opposite effect on atmospheric <em>p</em>CO₂ during the maxima of the grand eccentricity cycles. Moreover, we found a distinct shift in the dominant signal from eccentricity to obliquity cycles recorded in the <em>p</em>CO₂, δ¹⁸O_benthic and GMSL datasets at ~13 Ma, a time when perennial sea ice occurred in the Arctic and significant ice growth shown in Antarctica. We suggest that the change in the type and distribution of the ice sheets would shift glacial response to orbital forcing and hence mediated global climate and <em>p</em>CO₂. Our analysis reveals a clear synchrony among atmospheric <em>p</em>CO₂, climate change, and the grand orbital cycles in the late Cenozoic.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141314768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rock glacier distribution across the Himalaya","authors":"Stephan Harrison ,&nbsp;Darren B. Jones ,&nbsp;Adina E. Racoviteanu ,&nbsp;Karen Anderson ,&nbsp;Sarah Shannon ,&nbsp;Richard A. Betts ,&nbsp;Ruolin Leng","doi":"10.1016/j.gloplacha.2024.104481","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104481","url":null,"abstract":"<div><p>In High Mountain Asia, human-induced climate warming threatens the cryosphere. Expected long-term reductions in future runoff from glacial catchments raises concerns regarding the sustainability of these natural ‘water towers’ and the implications of reduced water availability for regional human and ecological systems. Ice-debris landforms (I-DL), containing ice whether moving or not include rock glaciers and ice-cored moraines, and are likely to be climatically more resilient than debris-covered and debris-free glaciers. Recent work has shown that rock glaciers contain globally valuable water supplies yet over High Mountain Asia information regarding their number, spatial distribution, morphometric characteristics and water content are scarce. Here, we present the first systematic estimate of the current extent and distribution of rock glaciers for a subset of High Mountain Asia (the Himalaya). A sample of 2070 intact and relict rock glaciers were digitized on Google Earth imagery from the Western, Central and Eastern Himalaya regions and then quantitative and qualitative characteristics were analysed regionally based on topographic data from the NASA Shuttle Radar Topography Mission (SRTM) Version 3.0 and then aggregated across the Himalaya using an “upscaling” method. The majority of the digitized landforms (∼65%) were categorised as intact rock glaciers (i.e., ice-debris Landforms, or I-DLs, containing ice) and the remainder as relict rock glaciers (i.e., discrete debris accumulations or DDAs, not containing ice). They range in elevation from 3225 to 5766 m a.s.l., with the lowest in the Central Himalaya. Sampled relict and intact rock glaciers are primarily situated on northern quadrants. Over the entire Himalaya, we identified ∼25,000 landforms, with a total estimated areal coverage of 3747 km². The area upscaling method was validated in the Manaslu region of Nepal using high-resolution Planet data (5 m) and freely available, fine spatial resolution optical satellite data accessed through Google Earth Pro and ESRI basemaps. In absence of complete rock glacier inventories over the Himalaya, our approach proves useful to investigate the nature, distribution and infer potential future behaviour of these landforms across the Himalaya in a changing climate.</p></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0921818124001280/pdfft?md5=386336226b3f279fccdee390d504eec0&pid=1-s2.0-S0921818124001280-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141324550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}