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Prediction of solar activities: Sunspot numbers and solar magnetic synoptic maps

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Science China earth sciences 2024年第8期67卷 2460-2477页

作者： Rui ZHUO Jiansen HE Die DUAN Rong LIN Ziqi WU Limei YAN Yong WEI School of earth and Space sciences Peking University College of Advanced Interdisciplinary Studies National University of Defense Technology Centre for Mathematical Plasma Astrophysics Department of MathematicsKU Leuven Key Laboratory of earth and planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences College of earth and planetary sciences University of Chinese Academy of Sciences

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 g7～0 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.

关键词： Solar activity prediction Solar magnetic field Spherical harmonic expansion Long-Short Term Memory (LSTM) Empirical Mode Decomposition (EMD)

Correcting Climate Model Sea Surface Temperature Simulations with Generative Adversarial Networks:Climatology,Interannual Variability,and Extremes

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Advances in Atmospheric sciences 2024年第7期41卷 1299-1312页

作者： Ya WANG Gang HUANG Baoxiang PAN Pengfei LIN Niklas BOERS Weichen TAO Yutong CHEN BO LIU Haijie LI State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China College of earth and planetary sciences University of Chinese Academy of SciencesBeijing 100049China earth System Modelling School of Engineering and DesignTechnical University of MunichOttobrunn 85521Germany Potsdam institute for Climate Impact Research Potsdam 14412Germany department of Mathematics and Global Systems institute University of ExeterExeter EX44QEUK CMA earth System Modeling and Prediction Centre(CEMC) Chinese Academy of Meteorological SciencesBeijing 100081China

Climate models are vital for understanding and projecting global climate change and its associated impacts.However,these models suffer from biases that limit their accuracy in historical simulations and the trustworthiness of future projections.Addressing these challenges requires addressing internal variability,hindering the direct alignment between model simulations and observations,and thwarting conventional supervised learning methods.Here,we employ an unsupervised Cycle-consistent Generative Adversarial Network(CycleGAN),to correct daily Sea Surface Temperature(SST)simulations from the Community earth System Model 2(CESM2).Our results reveal that the CycleGAN not only corrects climatological biases but also improves the simulation of major dynamic modes including the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole mode,as well as SST extremes.Notably,it substantially corrects climatological SST biases,decreasing the globally averaged Root-Mean-Square Error(RMSE)by 58%.Intriguingly,the CycleGAN effectively addresses the well-known excessive westward bias in ENSO SST anomalies,a common issue in climate models that traditional methods,like quantile mapping,struggle to rectify.Additionally,it substantially improves the simulation of SST extremes,raising the pattern correlation coefficient(PCC)from 0.56 to 0.88 and lowering the RMSE from 0.5 to 0.32.This enhancement is attributed to better representations of interannual,intraseasonal,and synoptic scales variabilities.Our study offers a novel approach to correct global SST simulations and underscores its effectiveness across different time scales and primary dynamical modes.

关键词： generative adversarial networks model bias deep learning El Niño-Southern Oscillation marine heatwaves

A lunar time scale from the perspective of the Moon’s dynamic evolution

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Science China earth sciences 2024年第1期67卷 234-251页

作者： Dijun GUO Jianzhong LIU James WHEAD Fuqin ZHANG Zongcheng LING Shengbo CHEN Jianping CHEN Xiaozhong DING Jinzhu JI Ziyuan OUYANG State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Center for Lunar and planetary sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China department of earth Environmental and Planetary SciencesBrown UniversityProvidence RI 02912USA institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China College of Geoexploration Science and Technology Jilin UniversityChangchun 130026China School of earth sciences and Resources China University of GeosciencesBeijing 100083China institute of Geology Chinese Academy of Geological SciencesBeijing 100037China School of Resources and Environmental Engineering Inner Mongolia University of TechnologyHohhot 010051China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230026China

A geologic time scale is a chronological system that separates the geological strata of a planetary body into different units in temporal sequence and shows its progressive evolution.The time scale of the Moon was established a half-century ago during the telescopic-early Apollo exploration era,using data with limited spatial coverage and resolution.The past decades have seen a wide array of studies,which have significantly extended our understanding of global lunar geologic evolution.Based on a comprehensive review of lunar evolution with respect to the dynamical changes,we propose two major updates to the current lunar time scale paradigm to include the evolution of both endogenic and exogenic dynamic forces now known to have influenced early lunar history.Firstly,based on the temporal interplay of exogenic and endogenic processes in altering the Moon,we defined three Eon/Eonothem-level units to represent three dynamical evolutionary phases.Secondly,the pre-Nectarian System is redefined and divided as the magma ocean-era Magma-oceanian System and the following Aitkenian System beginning with the South Pole-Aitken basin.The ejecta of this basin,Das Formation,was deposited on the primordial lunar crust as the oldest stratum produced from exogenic processes.The updated lunar time scale,facilitated by the post-Apollo exploration and research advances,provides an integrated framework to depict the evolution of the Moon and has important implications for the geologic study of other terrestrial planets.

关键词： The Moon Geologic time scale Evolution history Endogenic process Exogenic process

Helmholtz decomposition with a scalar Poisson equation in elastic anisotropic media

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Petroleum Science 2024年第3期21卷 1597-1610页

作者： Xin-Yu Fang Gang Yao Qing-Qing Zheng Ping-Min Zhang Di Wu Feng-Lin Niu State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum (Beijing) Unconventional Petroleum Research institute China University of Petroleum (Beijing) department of Mathematics College of Science China University of Petroleum (Beijing) College of Geophysics China University of Petroleum (Beijing) department of earth Environmental and Planetary Sciences Rice University

P-and S-wave separation plays an important role in elastic reverse-time migration. It can reduce the artifacts caused by crosstalk between different modes and improve image quality. In addition, P-and Swave separation can also be used to better understand and distinguish wave types in complex media. At present, the methods for separating wave modes in anisotropic media mainly include spatial nonstationary filtering, low-rank approximation, and vector Poisson equation. Most of these methods require multiple Fourier transforms or the calculation of large matrices, which require high computational costs for problems with large scale. In this paper, an efficient method is proposed to separate the wave mode for anisotropic media by using a scalar anisotropic Poisson operator in the spatial domain.For 2D problems, the computational complexity required by this method is 1/2 of the methods based on solving a vector Poisson equation. Therefore, compared with existing methods based on pseudoHelmholtz decomposition operators, this method can significantly reduce the computational cost. Numerical examples also show that the P and S waves decomposed by this method not only have the correct amplitude and phase relative to the input wavefield but also can reduce the computational complexity significantly.

关键词： Anisotropic media Scalar anisotropic Poisson equation Improved elastic wavefield decomposition

Spatiotemporal evolution of surface urban heat islands: Concerns regarding summer heat wave periods

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Journal of Geographical sciences 2024年第6期34卷 1065-1082页

作者： REN Jiayi YANG Jun YU Wenbo CONG Nan XIAO Xiangming XIA Jianhong(Cecilia) LI Xueming School of Humanities and Law Northeastern UniversityShenyang 110169China Human Settlements Research Center Liaoning Normal UniversityDalian 116029LiaoningChina Jangho Architecture College Northeastern UniversityShenyang 110169China Lhasa Plateau Ecosystem Research Station Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China department of Microbiology and Plant Biology Center for Earth Observation and ModelingUniversity of OklahomaNormanOK 73019USA School of earth and planetary sciences(EPS) Curtin UniversityPerth 65630Australia

Many cities face heat wave(HW) events, combined with the existent surface urban heat island(SUHI) effects. This places pressure on human settlements and sustainable development. However, few studies have investigated the SUHI effects from the perspective of HWs. In this study, the summer HWs in Beijing from 2001 to 2021 were calculated, and the evolution of HWs and SUHIs was quantitatively analyzed based on the dynamic nature of the urban-rural boundary. Beijing experienced 27 HWs in the 21 years, including 10 instances in June, four in July, and 13 in August. The SUHI varied during HWs, between 2–3°C in most years. The highest SUHI occurred in 2019, reaching 3.99°C and covering the largest area(10,887 km~2). The fluctuation in HWs and SUHIs generally displayed the same spatiotemporal pattern, and HWs amplified the SUHIs to a certain extent, with the highest correlation coefficient being 0.44. Additionally, impervious surfaces and cropland contributed most to SUHIs,and night light enhanced SUHIs. Observing the co-evolution of HWs and SUHIs will be helpful for ecological maintenance and urban infrastructure optimization and provide theoretical support for reducing heat risk and improving the human settlement environment.

关键词： heat wave surface urban heat island interactive Self-organization algorithm centroid migration Beijing

Implementation of a particle-in-cell method for the energy solver in 3D spherical geodynamic modeling

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earth and planetary Physics 2024年第3期8卷 549-563页

作者： Hao Dong ZeBin Cao LiJun Liu YanChong Li SanZhong Li LiMing Dai XinYu Li Frontiers Science Center for Deep Ocean Multispheres and earth System Key Laboratory of Submarine Geosciences and Prospecting TechniquesMinistry of Education and College of Marine GeosciencesOcean University of ChinaQingdao 266100China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China department of earth Science&Environmental Change University of Illinois at Urbana-ChampaignUrbanaIL 61801USA Laboratory of Seismology and Physics of earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The thermal evolution of the earth’s interior and its dynamic effects are the focus of earth sciences.However,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially in the presence of sharp thermal gradients,such as when modeling subducting slabs and rising plumes.This phenomenon prohibits the correct representation of thermal evolution and may cause incorrect implications of geodynamic processes.After examining several approaches for removing these numerical oscillations,we show that the Lagrangian method provides an ideal way to solve this problem.In this study,we propose a particle-in-cell method as a strategy for improving the solution to the energy equation and demonstrate its effectiveness in both one-dimensional and three-dimensional thermal problems,as well as in a global spherical simulation with data assimilation.We have implemented this method in the open-source finite-element code CitcomS,which features a spherical coordinate system,distributed memory parallel computing,and data assimilation algorithms.

关键词： numerical oscillation overshooting and undershooting particle-in-cell method three-dimensional spherical geodynamic modeling energy solver finite element method

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厄尔尼诺-南方涛动研究进展

科学通报 2024年第8期69卷 1047-1057页

作者：张晓琳马永星大连海事大学航海学院大连116085 department of earth and planetary sciences Kyushu UniversityFukuoka 819-0395Japan Fisheries and Oceans Canada Bedford Institute of OceanographyDartmouth B2Y 4A2Canada

厄尔尼诺-南方涛动(El Nino and Southern Oscillation,ENSO)对全球气候都具有重要的影响,如印度洋季风、秘鲁沿岸的渔业生产以及北美的气候等.过去的研究在ENSO的观测、理论、预报和数值模拟等方面都取得了长足的进展,但依然有很多问... 详细信息

厄尔尼诺-南方涛动(El Nino and Southern Oscillation,ENSO)对全球气候都具有重要的影响,如印度洋季风、秘鲁沿岸的渔业生产以及北美的气候等.过去的研究在ENSO的观测、理论、预报和数值模拟等方面都取得了长足的进展,但依然有很多问题尚待解决.本文简要地回顾了过去在ENSO的相关理论、预报、非对称性以及年代际变化、古气候下的变化以及数值模拟方面的研究:首先回顾了ENSO盛行的几组理论,具体包括Bjerknes正反馈机制、延迟振子理论、充放电振子理论、平流反射振子理论以及西太平洋振子理论.其次,系统地总结了厄尔尼诺常用的预报方法以及预报因子(如暖水体积、西太平洋风场、印度洋-太平洋风场的积分及赤道流场等),并讨论了目前预报仍然存在的局限性;非对称性和年代际变化是ENSO重要的特征,本文详细地阐述了这方面的相关研究进展及存在的问题.再次,介绍了关于ENSO的古气候研究目前所取得的成果以及主要结论,并对数值模拟方面仍然存在的问题及ENSO对其他海盆的影响进行了讨论;最后,对上述相关方面存在的不足以及亟待解决的问题进行了探讨和总结.

关键词：厄尔尼诺-南方涛动动力学机制预报古气候盐度海盆间相互作用

Himalayas as a global hot spot of springtime stratospheric intrusions:Insight from isotopic signatures in sulfate aerosols

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Research in Cold and Arid Regions 2024年第1期16卷 5-13页

作者： Kun Wang ShiChang Kang Mang Lin PengFei Chen ChaoLiu Li XiuFeng Yin Shohei Hattori Teresa L.Jackson JunHua Yang YiXi Liu Naohiro Yoshida Mark HThiemens State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences(CAS)LanzhouGansu 730000China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryCASGuangzhouGuangdong 510640China University of Chinese Academy of sciences Beijing 100049China International Center for Isotope Effects Research(ICIER) School of Earth Sciences and EngineeringNanjing UniversityNanjingJiangsu 210023China Frontiers Science Center for Critical earth Material Cycling State Key Laboratory for Mineral Deposits ResearchSchool of Earth Sciences and EngineeringNanjing UniversityNanjingJiangsu 210023China department of Chemical Science and Engineering School of Materials and Chemical TechnologyTokyo Institute of Technology4259 Nagatsuta-choMidori-kuYokohamaKanagawa 226-8502Japan department of Chemistry and Biochemistry University of California San DiegoLa JollaCA 92093-0021USA earth-Life Science institute Tokyo Institute of TechnologyMeguro-kuTokyo 152-8551Japan National institute of Information and Communications Technology KoganeiTokyo 184-8795Japan

Downward transport of stratospheric air into the troposphere(identified as stratospheric intrusions)could potentially modify the radiation budget and chemical of the earth's surface atmosphere.As the highest and largest plateau on earth,the Tibetan Plateau including the Himalayas couples to global climate,and has attracted widespread attention due to rapid warming and cryospheric shrinking.Previous studies recognized strong stratospheric intrusions in the Himalayas but are poorly understood due to limited direct evidences and the complexity of the meteorological dynamics of the third pole.Cosmogenic^(35)S is a radioactive isotope predominately produced in the lower stratosphere and has been demonstrated as a sensitive chemical tracer to detect stratospherically sourced air mass in the planetary boundary layer.Here,we report 6-month(April–September 2018)observation of^(35)S in atmospheric sulfate aerosols(^(35)SO_(4)^(2-))collected from a remote site in the Himalayas to reveal the stratospheric intrusion phenomenon as well as its potential impacts in this region.Throughout the sampling campaign,the^(35)SO_(4)^(2-)concentrations show an average of 1,070±980 atoms/m^(3).In springtime,the average is 1,620±730 atoms/m^(3),significantly higher than the global existing data measured so far.The significant enrichments of^(35)SO_(4)^(2-)measured in this study verified the hypothesis that the Himalayas is a global hot spot of stratospheric intrusions,especially during the springtime as a consequence of its unique geology and atmospheric couplings.In combined with the ancillary evidences,e.g.,oxygen-17 anomaly in sulfate and modeling results,we found that the stratospheric intrusions have a profound impact on the surface ozone concentrations over the study region,and potentially have the ability to constrain how the mechanisms of sulfate oxidation are affected by a change in plateau atmospheric properties and conditions.This study provides new observational constraints on stratospheric intrusions in the Himalayas,which woul

关键词： Himalayas Stratospheric intrusions Cosmogenic^(35)SO_(4)^(2-) Ozone Atmospheric oxidation

A progress review of black carbon deposition on Arctic snow and ice and its impact on climate change

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Advances in Polar Science 2024年第2期35卷 178-191页

作者： ZHANG Zilu ZHOU Libo ZHANG Meigen department of Lower Atmosphere Observation Research(LAOR) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of earth and planetary Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The rapid warming of the Arctic,accompanied by glacier and sea ice melt,has significant consequences for the earth’s climate,ecosystems,and economy.Black carbon(BC)deposition on snow and ice can trigger a significant reduction in snow albedo and accelerate melting of snow and ice in the Arctic.By reviewing the published literatures over the past decades,this work provides an overview of the progress in both the measurement and modeling of BC deposition and its impact on Arctic climate change.In summary,the maximum value of BC deposition appears in the western Russian Arctic(26 ng·g^(–1)),and the minimum value appears in Greenland(3 ng·g^(–1)).BC records in the Arctic ice core already peaked in 1920s and 1970s,and shows a regional difference between Greenland and Canadian Arctic.The different temporal variations of Arctic BC ice core records in different regions are closely related to the large variability of BC emissions and transportation processes across the Arctic region.Model simulations usually underestimate the concentration of BC in snow and ice by 2–3 times,and cannot accurately reflect the seasonal and regional changes in BC deposition.Wet deposition is the main removal mechanism of BC in the Arctic,and observations show different seasonal variations in BC wet deposition in Ny-Ålesund and Barrow.This discrepancy may result from varying contributions of anthropogenic and biomass burning(BB)emissions,given the strong influence by BC from BB emissions at Barrow.Arctic BC deposition significantly influences regional climate change in the Arctic,increasing fire activities in the Arctic have made BB source of Arctic BC more crucial.On average,BC in Arctic snow and ice causes an increase of+0.17 W·m^(–2)in radiative forcing and 8 Gt·a^(–1)in runoff in Greenland.As stressed in the latest Arctic Monitoring and Assessment Programme report,reliable source information and long-term and high-resolution observations on Arctic BC deposition will be crucial for a more comprehensive understanding and a better mitigation

关键词： Arctic climate black carbon albedo snow deposition