Science China Earth Sciences最新文献

{"title":"Stable hydrogen isoscape in precipitation generated using data fusion for East China","authors":"Jiacheng Chen, Jie Chen, Xunchang John Zhang, Peiyi Peng","doi":"10.1007/s11430-023-1377-0","DOIUrl":"https://doi.org/10.1007/s11430-023-1377-0","url":null,"abstract":"<p>The stable hydrogen isotope in precipitation is an effective environmental tracer for climatic and hydrologic studies. However, accurate and high-precision precipitation hydrogen isoscapes are currently unavailable in China. In this study, a data fusion method based on Convolutional Neural Networks (CNN) is used to fuse the hydrogen isotopic composition (<i>δ</i>²H_p) of observations and isotope-equipped general circulation model (iGCM) simulations. A precipitation hydrogen isoscape with a temporal resolution of monthly and a spatial resolution of 50–60 km is established for East China for the 1969–2017 period. Prior to building the isoscape, the performance of three data fusion methods (DFMs) and two bias correction methods (BCMs) is compared. The results indicate that the CNN fusion method performs the best with a correlation coefficient larger than 0.90 and root mean square error smaller than 10.5‰when using observation as a benchmark. The fusion methods based on back propagation and long short-term memory neural network perform similarly, while slightly outperforming the bias correction methods. Thus, the CNN method is used to generate the hydrogen isoscape, and the temporal and spatial distribution characteristics of the hydrogen isotope in precipitation are analyzed based on this dataset. The generated isoscape shows similar spatial and temporal distribution characteristics to observations. In general, the distribution pattern of <i>δ</i>²H_p is consistent with the temperature effect in northern China, and consistent with the precipitation amount effect in southern China. The trend of the <i>δ</i>²H_p time series is consistent with that of observed precipitation and temperature. Overall, the generated isoscape effectively reproduces the observations, and has the characteristics of time continuity and relative spatial regularity, which can provide valuable data support for tracking atmospheric and hydrological processes.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"36 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The δ15N values of foxtail millet (Setaria italica) and common millet (Panicum miliaceum) are reliable indicators of manuring practices","authors":"Jishuai Yang, Xiaoyan Yang, Ting You, Fahu Chen","doi":"10.1007/s11430-023-1376-y","DOIUrl":"https://doi.org/10.1007/s11430-023-1376-y","url":null,"abstract":"<p>Millet agriculture, which originated in northern China, alongside rice agriculture, have nurtured the Chinese civilization. Prehistoric manuring practices likely promoted and maintained sustainable millet agricultural production in the loess area of northern China. However, ongoing controversy exists regarding the indicators of prehistoric manuring intensity of foxtail millet (<i>Setaria italica</i>) and common millet (<i>Panicum miliaceum</i>). Here, we present the results of pot and field fertilization experiments on two millet types. Our findings suggest that manuring can significantly increase the <i>δ</i>¹⁵N values of foxtail millet, and its <i>δ</i>¹⁵N values increase with increasing manuring levels. The <i>δ</i>¹⁵N values of foxtail millet leaves are systematically greater than those of grains by approximately 1.6‰. Manuring could have a long-term residual impact on increasing the <i>δ</i>¹⁵N values of soil and millet crops. Combined with previous crop fertilization experiment results, we propose that the impact of manuring on the <i>δ</i>¹⁵N values of non-nitrogen-fixing crops is roughly consistent. The <i>δ</i>¹⁵N value and amount of manure are key factors determining the extent of change in plant <i>δ</i>¹⁵N values. The millet grain <i>δ</i>¹⁵N values can serve as reliable indicators of manuring practices. Finally, we provide an interpretive framework for assessing the correlation between manuring levels and the <i>δ</i>¹⁵N values of archaeological millet remains. The <i>δ</i>¹⁵N values of ancient millet grains suggest widespread and intensive manuring practices in prehistoric millet agriculture in northern China, spanning from the early Yangshao period to the Longshan period.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"26 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Explainable artificial intelligence models for mineral prospectivity mapping","authors":"Renguang Zuo, Qiuming Cheng, Ying Xu, Fanfan Yang, Yihui Xiong, Ziye Wang, Oliver P. Kreuzer","doi":"10.1007/s11430-024-1309-9","DOIUrl":"https://doi.org/10.1007/s11430-024-1309-9","url":null,"abstract":"<p>Mineral prospectivity mapping (MPM) is designed to reduce the exploration search space by combining and analyzing geological prospecting big data. Such geological big data are too large and complex for humans to effectively handle and interpret. Artificial intelligence (AI) algorithms, which are powerful tools for mining nonlinear mineralization patterns in big data obtained from mineral exploration, have demonstrated excellent performance in MPM. However, AI-driven MPM faces several challenges, including difficult interpretability, poor generalizability, and physical inconsistencies. In this study, based on previous studies, we devised a novel workflow that aims to constructing more transparent and explainable artificial intelligence (XAI) models for MPM by embedding domain knowledge throughout the AI-driven MPM, from input data to model design and model output. This newly proposed approach provides strong geological and conceptual leads that guide the entire AI-driven MPM model training process, thereby improving model interpretability and performance. Overall, the development of XAI models for MPM is capable of embedding prior and expert knowledge throughout the modeling process, presenting a valuable and promising area for future research designed to improve MPM.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"32 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monazite U-Th-Pb and sericite Rb-Sr dating of the Xiajiadian black shale-hosted gold deposit in the Qinling orogen, central China: Implications for regional gold metallogeny","authors":"Xueling Yu, Jianwei Li, Xiaoye Jin, Shaorui Zhao, Chongguo He, Yunlong Zhu","doi":"10.1007/s11430-023-1322-y","DOIUrl":"https://doi.org/10.1007/s11430-023-1322-y","url":null,"abstract":"&lt;p&gt;The Qinling orogen in central China contains several black shale-hosted gold deposits, but the age of their formation and a possible relation between gold mineralization and regional tectonism remain undetermined. Here we present results of &lt;i&gt;in situ&lt;/i&gt; monazite U-Th-Pb dating and sericite Rb-Sr dating of the Xiajiadian black shale-hosted gold deposit to provide tight constraints on the time of gold deposition and information on the tectonic setting under which the deposit formed. The Xiajiadian gold deposit is mainly hosted in black shales of the Lower Cambrian Shuigoukou formation, with minor ores contained in sandy conglomerate of the Lower Devonian Xichahe formation. Gold ores in the black shales have been intensively oxidized and consist mainly of hematite, goethite, gypsum, quartz, calcite, native gold, and unrecognized iron oxides. However, gold ores in the sandy conglomerate are free of oxidation and thus provide an opportunity to date the formation of the Xiajiadian gold deposit. The ores consist of pyrite, marcasite, sericite, and quartz, which are associated with a variety of accessory minerals, including monazite, apatite, and titanite. Gold is mainly present as structure-bound ions or nanoparticles in pyrite and marcasite, but minor native gold grains also occur as inclusions in pyrite. Monazite is well developed in the ores, and has close textural association with Au-bearing pyrite and marcasite. Most monazite grains have zoned textures consisting of a core area (Mnz1) and an overgrowth zone (Mnz2). Mnz1 contains 4.8–13 wt.% ThO&lt;sub&gt;2&lt;/sub&gt; and shows large variations in HREE and prominent negative Eu anomalies in the chondrite-normalized REE patterns. It yields common lead-corrected &lt;sup&gt;208&lt;/sup&gt;Pb/&lt;sup&gt;232&lt;/sup&gt;Th dates ranging from 910±10 to 416±4 Ma (2σ). These dates are interpreted in terms of a detrital origin for monazite in the core area. Mnz2 has much lower ThO&lt;sub&gt;2&lt;/sub&gt; contents of 0.8–1.7 wt.% and shows weak negative Eu anomalies in the chondrite-normalized REE patterns. It yields common lead-corrected &lt;sup&gt;208&lt;/sup&gt;Pb/&lt;sup&gt;232&lt;/sup&gt;Th dates of 229–209 Ma (2σ) with a weighted mean of 217.6±3.0 Ma (2σ), which is considered as the time of Mnz2 crystallization. Sericite in gold ores and associated alteration zones has close relations to Au-bearing pyrite and marcasite, and yields a well-defined Rb-Sr isochron age of 222.2±3.3 Ma (2σ). The sericite Rb-Sr age is indistinguishable within analytical errors from the weighted mean Th-Pb age of Mnz2. The age data presented here indicate that the Xiajiadian gold deposit formed at ca. 220 Ma in the Late Triassic (Norian). We therefore suggest that gold mineralization at Xiajiadian occurred during the transitional stage from oceanic subduction to continental collision that led to the formation of the Qinling orogen. During this stage, metamorphic devolatization of the underlying Early Paleozoic to Proterozoic carbonaceous sequences likely supplied ore fluids from which the Xiaj","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"64 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elevation of basal lacustrine sediments along the mid-lower reaches of the Yangtze River and its implications for the reconstruction of Holocene water levels","authors":"Shuchun Yao, Chunhai Li, Bin Xue","doi":"10.1007/s11430-023-1374-y","DOIUrl":"https://doi.org/10.1007/s11430-023-1374-y","url":null,"abstract":"<p>The middle and lower reaches of the Yangtze River, a primary region for freshwater lakes in China, have undergone significant transformations throughout the Holocene. These changes, driven by factors such as sea-level rise, climate change, and human activities, have led to the progressive elevation of water levels in this area. As a result, a floodplain has emerged, characterized by the formation of numerous shallow lakes along the river course. However, the pattern of water-level changes in the main channel of the Yangtze River during the Holocene remains unclear. This gap in knowledge poses challenges for understanding sediment transport dynamics, the interactions between the river and its adjacent lakes, and the prevention and control of flood disasters in the Yangtze River basin. To shed light on these issues, our study compiled data on the surface elevation and water depth of 81 lakes in the mid-lower reaches of the Yangtze River basin. Additionally, we analyzed historical water-level records from the 1900s to the 1970s at eight gauging stations from Shashi to Jiangyin along the river’s main stream. Our findings reveal that, particularly along the Jingjiang section, the basal elevation of most lakes is lower than the Yangtze River’s water level during the dry season. Conversely, the water level of the main stream exceeds that of both the floodplain and the lakes enclosed by the Jingjiang embankment. In the tidal reach, especially within the Taihu Lake basin, the basal elevation of lakes typically falls below sea level. Meanwhile, lakes located along the section from Chenglingji to Wuhu exhibit basal elevations that correspond with the Yangtze River’s annual average and dry season water levels. Given the widespread presence of lakes along the middle and lower reaches of the Yangtze River, our study introduces a new proxy for reconstructing the mean water level of the mid-lower Yangtze River in the Holocene. By analyzing sediments from Nanyi Lake and Chenyao Lake in the lower Yangtze River, we attempted to reconstruct the water level of the Yangtze River’s main channel since 8 ka BP.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"43 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Status and trends in the stability of the three largest ice shelves in Antarctica","authors":"Rongxing Li, Guojun Li, Lu An, Menglian Xia, Da Lv, Yuan Cheng, Aiguo Zhao, Tian Chang, Xiangbin Cui, Shengkai Zhang, Shijie Liu, Yixiang Tian, Weian Wang","doi":"10.1007/s11430-023-1338-8","DOIUrl":"https://doi.org/10.1007/s11430-023-1338-8","url":null,"abstract":"<p>The Ross, Filchner-Ronne, and Amery ice shelves are the three largest ice shelves in Antarctica, playing a crucial role in supporting the Antarctic ice sheet. However, current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors, lacking a comprehensive assessment of multiple parameters. To systematically and in-depth study the stability and trend of the three largest ice shelves, we comprehensively collected and analyzed key parameters, including elevation changes, basal melting, surface meltwater, major rifts propagation rate, suture zones, ice front area change rate, grounding lines, ice velocity, and mass balance. Additionally, we selected the collapsed Larsen B Ice Shelf (LBIS), the rapidly changing and structurally weakened Pine Island Ice Shelf (PIIS), and the accelerating Totten Ice Shelf (TIS) as reference ice shelves. By comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves, we find the status and trends in the stability of the latter. Our findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice shelves. Specifically, 50% of the parameters are smaller than those of the accelerating TIS, 88% are smaller than those of the rapidly changing PIIS, and all parameters are smaller than those of the collapsed LBIS. Furthermore, after analyzing parameters that are not smaller than those of the TIS, it is observed that they remain in a stable state. Hence, the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short term. Nevertheless, the evolution of the ice shelves under global climate change remains uncertain, making long-term observation and monitoring essential to assess their impact on sea level rise.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"64 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Segmental nature of the Red River fault revealed by seismic anisotropy and geological structures","authors":"Ying Li, Yuan Gao","doi":"10.1007/s11430-023-1311-0","DOIUrl":"https://doi.org/10.1007/s11430-023-1311-0","url":null,"abstract":"<p>As the western boundary of the Sichuan-Yunnan block (SYB), the Red River fault (RRF) is a major fault that controls deep crustal movement and deformation in the southeast margin of the Tibetan Plateau and regulates middle-lower crustal flow. Geophysical data suggest that the RRF is segmented and exhibits distinct variations in seismicity, velocity structure and crustal deformation from north to south. Seismic anisotropy reveals a complex pattern of lateral spatial and vertical stratified distributions. (1) From the perspective of crustal stratification, in the upper crust, the fast wave polarization in the north segment of the RRF is complex and possibly influenced by the Sanjiang lateral collision zone and adjacent faults with varying strikes. The fast wave polarization in the middle segment is in the NW-SE direction, indicating a localized area of closed down or locked up with consistent deformation. And in the south segment, it presents a disordered pattern, signifying complex deep tectonics and stress conditions at the wedged intersection zone. In the middle-lower crust in the north and south segments of the RRF, the azimuthal anisotropy is strong and consistent with the spatial strike of the weak zone characterized by low-velocity and high-conductivity. This suggests a connection between the anisotropy and the material migration. (2) In the whole crustal scale, the fast wave directions in two sides of the RRF are consistent with the NW-SE tectonic strike. It indicates that the RRF, as a large fault potentially cutting through the whole crust, strongly controls the surrounding media. (3) In the lithospheric scale, the fast wave polarizations are oriented nearly E-W and independent of the fault strike, consistent with the low P- and S-wave velocity structures and positive radial anisotropy in the upper mantle. The fast wave directions could be related to lithospheric olivine deformation and asthenospheric flow. This paper suggests a decoupling of deformation between the crust and the lithospheric mantle in the south of approximately 26°20′N near the RRF, which can potentially be attributed to the subduction and rollback of the Indian plate. Based on various geophysical observations and inversions, we can determine the detailed anisotropic structure in the crust and the upper mantle around the RRF. Denser geophysical arrays and more accurate records can be used to explore the intricate anisotropy in segmentation and stratification around the RRF, enhancing the understanding of its tectonic significance.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"14 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismicity changes and numerical simulation of coseismic deformation following the 2022 Ms6.8 Luding earthquake in Sichuan, China","authors":"Qiu Meng, Zitao Wang, Huai Zhang","doi":"10.1007/s11430-023-1314-6","DOIUrl":"https://doi.org/10.1007/s11430-023-1314-6","url":null,"abstract":"&lt;p&gt;The Xianshuihe fault is a major tectonic boundary between the Sichuan-Yunnan rhombic and Bayanhar blocks in Southwest China. With an average left-lateral strike-slip movement of 10–15 mm/yr, it is a fast-moving strike-slip continental fault. On September 5, 2022, the &lt;i&gt;M&lt;/i&gt;&lt;sub&gt;s&lt;/sub&gt;6.8 Luding earthquake occurred along the Moxi segment of the Xianshuihe fault, reaching a maximum intensity of IX and resulting in a significant number of casualties and severe property damage. This earthquake broke the long-standing seismic quiescence of the Xianshuihe fault, which lasted for more than 40 years, and was followed by a significant number of aftershocks. An outstanding question is how the behavior of the Xianshuihe fault and major earthquakes changed following this mainshock. In this study, we examined the changes in regional seismicity following the Luding earthquake and identified the potential for future strong earthquakes along the Xianshuihe fault. We used a finite element numerical method to simulate the environment of the seismogenic fault and its adjacent areas. In addition, we used the coseismic slip model of the Luding earthquake with the split-node method to calculate how the stress and strain fields in the surrounding area were affected by the 2022 mainshock. Coulomb stress changes were resolved in the main faults, and the seismicity of adjacent faults was analyzed in conjunction with the observed seismic data. The results indicate that regional tectonic movement primarily occurred to the southeast along the Moxi segment. The stress field is approximately north-south in tension and east-west in compression. Variation in the stress field in the epicentral region of the Luding earthquake exceeded 1 MPa. The maximum displacement of the coseismic deformation field was concentrated between Moxi town and Tuanjie village, and the Coulomb stress of the fault zone in this region experienced the largest decrease. However, the &lt;i&gt;b&lt;/i&gt;-value of the Gutenberg-Richter magnitude-frequency relationship at the epicenter and the surrounding area exhibited an abnormal pattern of decrease-decrease-increase, indicating that the regional stress may not be fully released. This earthquake increased the Coulomb stress in other segments of the Xianshuihe, Anninghe, and Daliangshan faults, whereas the Coulomb stress in the Longmenshan and Xiaojinhe fault zones decreased. In addition, it triggered a series of normal-fault, moderate-sized earthquakes in nearby areas. The Dagangshan reservoir, located ∼20 km from the epicenter of the Luding earthquake, received an increase of ∼5.3 MPa in the tensile stress along the NWW-SEE direction. The Xiluodu Reservoir, located approximately 225 km from the epicenter, was less affected by this earthquake, and the seismic activity near the reservoir remained relatively unchanged. In this study, post-earthquake seismicity in the vicinity of the &lt;i&gt;M&lt;/i&gt;&lt;sub&gt;s&lt;/sub&gt;6.8 Luding earthquake was analyzed and predicted by numerical si","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"138 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating CMIP6 models in simulating the North Pacific decadal variability in sea surface salinity","authors":"Jian Chen, Hailong Liu, Pengfei Lin, Wenrong Bai, Chengzu Bai, Lu Wang","doi":"10.1007/s11430-023-1373-8","DOIUrl":"https://doi.org/10.1007/s11430-023-1373-8","url":null,"abstract":"<p>The North Pacific sea surface salinity (SSS) decadal variability (NPSDV) and its potential forcing were evaluated from 25 coupled models of the Coupled Model Intercomparison Project phase 6 (CMIP6) considering the prospects for decadal climate predictions. The results indicated that the CMIP6 models generally reproduced the spatial patterns of NPSDV. The large standard deviation of the SSS anomaly over the strong current regions, such as the Kuroshio-Oyashio Extension (KOE), North Pacific Current (NPC), California Current System (CCS), and Alaskan Coastal Current (ACC), is reflected in the two leading modes of NPSDV: a dipole with out-of-phase loadings in the KOE-NPC versus CCS-ACC and a monopole with positive loading over the KOE-NPC. The order of modes is sensitive to individual models that exhibit discrepancies, especially in temporal phases and power spectra. An autoregressive model of order-1 was used to reconstruct the NPSDV with several forcing terms. The generally weaker influence of forcings in an autoregressive model of order-1 is partly related to the overestimated response time of NPSDV relative to forcings. Most NPSDV variances originate from the persistence of SSS anomalies, but the dominant forcing factors are diverse among models. The model diversity for the NPSDV simulation mainly arises from the influence of the tropical El Niño-Southern Oscillation through teleconnection on the North Pacific Oscillation or Aleutian Low with timescale dependence. Conversely, models that can reproduce the NPSDV well are not dependent on those with larger impacts from the North Pacific oceanic processes.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"42 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of solar activities: Sunspot numbers and solar magnetic synoptic maps","authors":"Rui Zhuo, Jiansen He, Die Duan, Rong Lin, Ziqi Wu, Limei Yan, Yong Wei","doi":"10.1007/s11430-023-1354-4","DOIUrl":"https://doi.org/10.1007/s11430-023-1354-4","url":null,"abstract":"<p>The evolution of solar magnetic fields is significant for understanding and predicting solar activities. And our knowledge of solar magnetic fields largely depends on the photospheric magnetic field. In this paper, based on the spherical harmonic expansion of the photospheric magnetic field observed by Wilcox Solar Observatory, we analyze the time series of spherical harmonic coefficients and predict Sunspot Number as well as synoptic maps for Solar Cycle 25. We find that solar maximum years have complex short-period disturbances, and the time series of coefficient <i>g</i>₇⁰ is nearly in-phase with Sunspot Number, which may be related to solar meridional circulation. Utilizing Long Short-Term Memory networks (LSTM), our prediction suggests that the maximum of Solar Cycle 25 is likely to occur in June 2024 with an error of 8 months, the peak sunspot number may be 166.9±22.6, and the next solar minimum may occur around January 2031. By incorporating Empirical Mode Decomposition, we enhance our forecast of synoptic maps truncated to Order 5, validating their relative reliability. This prediction not only addresses a gap in forecasting the global distribution of the solar magnetic field but also holds potential reference value for forthcoming solar observation plans.</p>","PeriodicalId":21651,"journal":{"name":"Science China Earth Sciences","volume":"20 1","pages":""},"PeriodicalIF":5.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}