首页 > 最新文献

Reviews of Geophysics最新文献

英文 中文
Late Quaternary Abrupt Climate Change in the Tropics and Sub-Tropics: The Continental Signal of Tropical Hydroclimatic Events (THEs) 热带和亚热带晚第四纪气候突变:热带水文气候事件的大陆信号
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-10-04 DOI: 10.1029/2020RG000732
Raymond S. Bradley, Henry F. Diaz

Tropical hydroclimatic events, characterized by extreme regional rainfall anomalies, were a recurrent feature of marine isotope stages 2–4 and involved some of the most abrupt and dramatic climatic changes in the late Quaternary. These anomalies were pervasive throughout the tropics and resulted from the southward displacement of the Hadley circulation and the Intertropical Convergence Zone (ITCZ) and its associated convective rainfall, modulated by regional factors. Lake sediments, stalagmites, and offshore marine sediments that integrate inland continental conditions provide a comprehensive record of these changes over the past ∼70,000 yr. Vast areas experienced severe drought while other areas recorded greatly increased rainfall. Within the uncertainties of dating, these tropical rainfall anomalies occurred very close in time (±102–103 yr) to the deposition of North Atlantic ice-rafted debris (IRD) that defines Heinrich events (HEs). The IRD record is a good proxy for the amount and distribution of additional freshwater forcing which was necessary to bring about a drastic reduction in the Atlantic Meridional Overturning Circulation (AMOC) strength during each HE. As a consequence of this reduction in AMOC and an abrupt expansion in the area of sea-ice, cooling of the North Atlantic and adjacent continents took place, with a rapid atmospheric response involving the southward displacement of the ITCZ and associated rainfall belts. The climatic consequences of this large-scale change in the Hadley circulation, modulated by regional factors, is clearly recorded throughout the tropics as a series of abrupt and extreme hydroclimatic events. Some of the physical mechanisms that may have played a role in those changes are discussed.

以极端区域降水异常为特征的热带水文气候事件是海洋同位素阶段2-4的一个反复出现的特征,涉及晚第四纪一些最突然和最剧烈的气候变化。这些异常在整个热带地区普遍存在,是由哈德利环流和热带辐合带(ITCZ)的南移及其相关的对流降雨引起的,并受到区域因子的调节。湖泊沉积物、石笋和近海海洋沉积物整合了内陆大陆条件,为过去~ 7万年的这些变化提供了全面的记录。大片地区经历了严重的干旱,而其他地区则记录了降雨量的大幅增加。在测年的不确定性范围内,这些热带降雨异常在时间上(±102-103年)与北大西洋冰筏碎片(IRD)沉积非常接近,后者定义了海因里希事件(HEs)。IRD记录很好地代表了额外淡水强迫的数量和分布,而额外淡水强迫是导致每次大暖期间大西洋经向翻转环流(AMOC)强度急剧减弱所必需的。由于AMOC的减少和海冰面积的突然扩大,北大西洋和邻近大陆发生了降温,并伴随一个快速的大气响应,包括ITCZ和相关雨带向南移动。哈德利环流的这种大规模变化的气候后果,受到区域因素的调节,在整个热带地区被清楚地记录为一系列突然和极端的水文气候事件。讨论了可能在这些变化中起作用的一些物理机制。
{"title":"Late Quaternary Abrupt Climate Change in the Tropics and Sub-Tropics: The Continental Signal of Tropical Hydroclimatic Events (THEs)","authors":"Raymond S. Bradley,&nbsp;Henry F. Diaz","doi":"10.1029/2020RG000732","DOIUrl":"https://doi.org/10.1029/2020RG000732","url":null,"abstract":"<p><b>Tropical hydroclimatic events</b>, characterized by extreme regional rainfall anomalies, were a recurrent feature of marine isotope stages 2–4 and involved some of the most abrupt and dramatic climatic changes in the late Quaternary. These anomalies were pervasive throughout the tropics and resulted from the southward displacement of the Hadley circulation and the Intertropical Convergence Zone (ITCZ) and its associated convective rainfall, modulated by regional factors. Lake sediments, stalagmites, and offshore marine sediments that integrate inland continental conditions provide a comprehensive record of these changes over the past ∼70,000 yr. Vast areas experienced severe drought while other areas recorded greatly increased rainfall. Within the uncertainties of dating, these tropical rainfall anomalies occurred very close in time (±10<sup>2</sup>–10<sup>3</sup> yr) to the deposition of North Atlantic ice-rafted debris (IRD) that defines Heinrich events (HEs). The IRD record is a good proxy for the amount and distribution of additional freshwater forcing which was necessary to bring about a drastic reduction in the Atlantic Meridional Overturning Circulation (AMOC) strength during each HE. As a consequence of this reduction in AMOC and an abrupt expansion in the area of sea-ice, cooling of the North Atlantic and adjacent continents took place, with a rapid atmospheric response involving the southward displacement of the ITCZ and associated rainfall belts. The climatic consequences of this large-scale change in the Hadley circulation, modulated by regional factors, is clearly recorded throughout the tropics as a series of abrupt and extreme hydroclimatic events. Some of the physical mechanisms that may have played a role in those changes are discussed.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 4","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000732","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6072902","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}
引用次数: 8
Origin, Accretion, and Reworking of Continents 大陆的起源、增生和改造
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-08-03 DOI: 10.1029/2019RG000689
Rixiang Zhu, Guochun Zhao, Wenjiao Xiao, Ling Chen, Yanjie Tang

The continental crust is unique to the Earth in the solar system, and controversies remain regarding its origin, accretion and reworking of continents. The plate tectonics theory has been significantly challenged in explaining the origin of Archean (especially pre-3.0 Ga) continents as they rarely preserve hallmarks of plate tectonics. In contrast, growing evidence emerges to support oceanic plateau models that better explain characteristics of Archean continents, including the bimodal volcanics and nearly coeval emplacement of tonalite-trondjhemite-granodiorite (TTG) rocks, presence of ∼1600°C komatiites and dominant dome structures, and lack of ultra-high-pressure rocks, paired metamorphic belts and ophiolites. On the other hand, the theory of plate tectonics has been successfully applied to interpret the accretion of continents along subduction zones since the late Archean (3.0–2.5 Ga). During subduction processes, the new mafic crust is generated at the base of continents through partial melting of mantle wedge with the addition of H2O-dominant fluids from subducted oceanic slabs and partial melting of the juvenile mafic crust results in the generation of new felsic crusts. This eventually leads to the outgrowth of continents. Subduction processes also cause softening, thinning, and recycling of continental lithosphere due to the vigorous infiltration of volatile-rich fluids and melts, especially along weak belts/layers, leading to widespread continental reworking and even craton destruction. Reworking of continents also occurs in continental interiors due to either plate boundary processes or plume-lithosphere interactions. The effects of plumes have proven to be less significant and cause lower degrees of lithospheric modification than subduction-induced craton destruction.

大陆地壳在太阳系中是地球所特有的,关于大陆的起源、大陆的增生和大陆的改造,一直存在争议。板块构造理论在解释太古宙(特别是3.0 Ga以前)大陆的起源方面受到了极大的挑战,因为它们很少保留板块构造的特征。相比之下,越来越多的证据支持海洋高原模型,该模型更好地解释了太古宙大陆的特征,包括双峰火山和近同时期的闪长岩(TTG)岩石侵位,~ 1600°C的科马陨石和主要的圆顶结构的存在,以及超高压岩石、对偶变质带和蛇绿岩的缺乏。另一方面,板块构造理论成功地解释了晚太古代(3.0-2.5 Ga)以来大陆沿俯冲带的增生。在俯冲过程中,地幔楔的部分熔融和俯冲洋板中以h2o为主的流体的加入在大陆底部形成新的基性地壳,幼基性地壳的部分熔融形成新的长英质地壳。这最终导致了大陆的形成。俯冲过程还导致大陆岩石圈的软化、变薄和再循环,这是由于富含挥发物的流体和熔体的强烈渗透,特别是沿着弱带/层,导致广泛的大陆改造甚至克拉通破坏。由于板块边界作用或地幔柱-岩石圈相互作用,大陆内部也会发生大陆的改造。与俯冲引起的克拉通破坏相比,羽流的影响已被证明不那么显著,对岩石圈的改造程度也较低。
{"title":"Origin, Accretion, and Reworking of Continents","authors":"Rixiang Zhu,&nbsp;Guochun Zhao,&nbsp;Wenjiao Xiao,&nbsp;Ling Chen,&nbsp;Yanjie Tang","doi":"10.1029/2019RG000689","DOIUrl":"https://doi.org/10.1029/2019RG000689","url":null,"abstract":"<p>The continental crust is unique to the Earth in the solar system, and controversies remain regarding its origin, accretion and reworking of continents. The plate tectonics theory has been significantly challenged in explaining the origin of Archean (especially pre-3.0 Ga) continents as they rarely preserve hallmarks of plate tectonics. In contrast, growing evidence emerges to support oceanic plateau models that better explain characteristics of Archean continents, including the bimodal volcanics and nearly coeval emplacement of tonalite-trondjhemite-granodiorite (TTG) rocks, presence of ∼1600°C komatiites and dominant dome structures, and lack of ultra-high-pressure rocks, paired metamorphic belts and ophiolites. On the other hand, the theory of plate tectonics has been successfully applied to interpret the accretion of continents along subduction zones since the late Archean (3.0–2.5 Ga). During subduction processes, the new mafic crust is generated at the base of continents through partial melting of mantle wedge with the addition of H<sub>2</sub>O-dominant fluids from subducted oceanic slabs and partial melting of the juvenile mafic crust results in the generation of new felsic crusts. This eventually leads to the outgrowth of continents. Subduction processes also cause softening, thinning, and recycling of continental lithosphere due to the vigorous infiltration of volatile-rich fluids and melts, especially along weak belts/layers, leading to widespread continental reworking and even craton destruction. Reworking of continents also occurs in continental interiors due to either plate boundary processes or plume-lithosphere interactions. The effects of plumes have proven to be less significant and cause lower degrees of lithospheric modification than subduction-induced craton destruction.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 3","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2019RG000689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5677212","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}
引用次数: 28
Reanalysis in Earth System Science: Toward Terrestrial Ecosystem Reanalysis 地球系统科学中的再分析:走向陆地生态系统的再分析
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-07-30 DOI: 10.1029/2020RG000715
R. Baatz, H. J. Hendricks Franssen, E. Euskirchen, D. Sihi, M. Dietze, S. Ciavatta, K. Fennel, H. Beck, G. De Lannoy, V. R. N. Pauwels, A. Raiho, C. Montzka, M. Williams, U. Mishra, C. Poppe, S. Zacharias, A. Lausch, L. Samaniego, K. Van Looy, H. Bogena, M. Adamescu, M. Mirtl, A. Fox, K. Goergen, B. S. Naz, Y. Zeng, H. Vereecken

A reanalysis is a physically consistent set of optimally merged simulated model states and historical observational data, using data assimilation. High computational costs for modeled processes and assimilation algorithms has led to Earth system specific reanalysis products for the atmosphere, the ocean and the land separately. Recent developments include the advanced uncertainty quantification and the generation of biogeochemical reanalysis for land and ocean. Here, we review atmospheric and oceanic reanalyzes, and more in detail biogeochemical ocean and terrestrial reanalyzes. In particular, we identify land surface, hydrologic and carbon cycle reanalyzes which are nowadays produced in targeted projects for very specific purposes. Although a future joint reanalysis of land surface, hydrologic, and carbon processes represents an analysis of important ecosystem variables, biotic ecosystem variables are assimilated only to a very limited extent. Continuous data sets of ecosystem variables are needed to explore biotic-abiotic interactions and the response of ecosystems to global change. Based on the review of existing achievements, we identify five major steps required to develop terrestrial ecosystem reanalysis to deliver continuous data streams on ecosystem dynamics.

再分析是一组物理上一致的最佳合并模拟模式状态和历史观测数据,使用数据同化。模拟过程和同化算法的高计算成本导致了分别针对大气、海洋和陆地的地球系统特定再分析产品。最近的发展包括先进的不确定度量化和陆地和海洋生物地球化学再分析的产生。本文综述了大气和海洋再分析,以及海洋和陆地生物地球化学再分析。特别是,我们确定了陆地表面,水文和碳循环重新分析,这些分析现在在非常具体的目的的目标项目中产生。虽然未来对陆地表面、水文和碳过程的联合再分析代表了对重要生态系统变量的分析,但生物生态系统变量仅在非常有限的程度上被同化。为了探索生物-非生物相互作用和生态系统对全球变化的响应,需要连续的生态系统变量数据集。在回顾现有成果的基础上,我们确定了发展陆地生态系统再分析以提供持续的生态系统动态数据流所需的五个主要步骤。
{"title":"Reanalysis in Earth System Science: Toward Terrestrial Ecosystem Reanalysis","authors":"R. Baatz,&nbsp;H. J. Hendricks Franssen,&nbsp;E. Euskirchen,&nbsp;D. Sihi,&nbsp;M. Dietze,&nbsp;S. Ciavatta,&nbsp;K. Fennel,&nbsp;H. Beck,&nbsp;G. De Lannoy,&nbsp;V. R. N. Pauwels,&nbsp;A. Raiho,&nbsp;C. Montzka,&nbsp;M. Williams,&nbsp;U. Mishra,&nbsp;C. Poppe,&nbsp;S. Zacharias,&nbsp;A. Lausch,&nbsp;L. Samaniego,&nbsp;K. Van Looy,&nbsp;H. Bogena,&nbsp;M. Adamescu,&nbsp;M. Mirtl,&nbsp;A. Fox,&nbsp;K. Goergen,&nbsp;B. S. Naz,&nbsp;Y. Zeng,&nbsp;H. Vereecken","doi":"10.1029/2020RG000715","DOIUrl":"https://doi.org/10.1029/2020RG000715","url":null,"abstract":"<p>A reanalysis is a physically consistent set of optimally merged simulated model states and historical observational data, using data assimilation. High computational costs for modeled processes and assimilation algorithms has led to Earth system specific reanalysis products for the atmosphere, the ocean and the land separately. Recent developments include the advanced uncertainty quantification and the generation of biogeochemical reanalysis for land and ocean. Here, we review atmospheric and oceanic reanalyzes, and more in detail biogeochemical ocean and terrestrial reanalyzes. In particular, we identify land surface, hydrologic and carbon cycle reanalyzes which are nowadays produced in targeted projects for very specific purposes. Although a future joint reanalysis of land surface, hydrologic, and carbon processes represents an analysis of important ecosystem variables, biotic ecosystem variables are assimilated only to a very limited extent. Continuous data sets of ecosystem variables are needed to explore biotic-abiotic interactions and the response of ecosystems to global change. Based on the review of existing achievements, we identify five major steps required to develop terrestrial ecosystem reanalysis to deliver continuous data streams on ecosystem dynamics.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 3","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6109191","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}
引用次数: 13
Structures and Deformation in Glaciers and Ice Sheets 冰川和冰原的结构和变形
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-07-27 DOI: 10.1029/2021RG000743
Stephen J. A. Jennings, Michael J. Hambrey

The aims of this review are to: (a) describe and interpret structures in valley glaciers in relation to strain history; and (b) to explore how these structures inform our understanding of the kinematics of large ice masses, and a wide range of other aspects of glaciology. Structures in glaciers give insight as to how ice deforms at the macroscopic and larger scale. Structures also provide information concerning the deformation history of ice masses over centuries and millennia. From a geological perspective, glaciers can be considered to be models of rock deformation, but with rates of change that are measurable on a human time-scale. However, structural assemblages in glaciers are commonly complex, and unraveling them to determine the deformation history is challenging; it thus requires the approach of the structural geologist. A wide range of structures are present in valley glaciers: (a) primary structures include sedimentary stratification and various veins; (b) secondary structures that are the result of brittle and ductile deformation include crevasses, faults, crevasse traces, foliation, folds, and boudinage structures. Some of these structures, notably crevasses, relate well to measured strain-rates, but to explain ductile structures analysis of cumulative strain is required. Some structures occur in all glaciers irrespective of size, and they are therefore recognizable in ice streams and ice shelves. Structural approaches have wide (but as yet under-developed potential) application to other sub-disciplines of glaciology, notably glacier hydrology, debris entrainment and transfer, landform development, microbiological investigations, and in the interpretation of glacier-like features on Mars.

本综述的目的是:(a)描述和解释与应变历史有关的山谷冰川结构;(b)探索这些结构如何告知我们对大冰块运动学的理解,以及冰川学的其他广泛方面。冰川的结构提供了关于冰如何在宏观和更大尺度上变形的见解。这些结构也提供了关于几个世纪和几千年来冰块变形历史的信息。从地质学的角度来看,冰川可以被认为是岩石变形的模型,但其变化率在人类的时间尺度上是可以测量的。然而,冰川中的结构组合通常是复杂的,解开它们以确定变形历史是具有挑战性的;因此,它需要构造地质学家的方法。峡谷冰川的构造种类繁多:(A)原生构造包括沉积分层和各种脉体;(b)次生构造是脆性和韧性变形的结果,包括裂缝、断层、裂缝痕迹、片理、褶皱和边界构造。其中一些结构,特别是裂缝,与测量的应变率有很好的关系,但为了解释延性结构,需要对累积应变进行分析。有些结构不论大小大小,都存在于所有冰川中,因此在冰流和冰架中都能辨认出来。结构方法在冰川学的其他分支学科中有广泛的应用(但潜力尚未开发),特别是冰川水文学、碎片夹带和转移、地貌发育、微生物研究以及对火星冰川样特征的解释。
{"title":"Structures and Deformation in Glaciers and Ice Sheets","authors":"Stephen J. A. Jennings,&nbsp;Michael J. Hambrey","doi":"10.1029/2021RG000743","DOIUrl":"https://doi.org/10.1029/2021RG000743","url":null,"abstract":"<p>The aims of this review are to: (a) describe and interpret structures in valley glaciers in relation to strain history; and (b) to explore how these structures inform our understanding of the kinematics of large ice masses, and a wide range of other aspects of glaciology. Structures in glaciers give insight as to how ice deforms at the macroscopic and larger scale. Structures also provide information concerning the deformation history of ice masses over centuries and millennia. From a geological perspective, glaciers can be considered to be models of rock deformation, but with rates of change that are measurable on a human time-scale. However, structural assemblages in glaciers are commonly complex, and unraveling them to determine the deformation history is challenging; it thus requires the approach of the structural geologist. A wide range of structures are present in valley glaciers: (a) primary structures include sedimentary stratification and various veins; (b) secondary structures that are the result of brittle and ductile deformation include crevasses, faults, crevasse traces, foliation, folds, and boudinage structures. Some of these structures, notably crevasses, relate well to measured strain-rates, but to explain ductile structures analysis of cumulative strain is required. Some structures occur in all glaciers irrespective of size, and they are therefore recognizable in ice streams and ice shelves. Structural approaches have wide (but as yet under-developed potential) application to other sub-disciplines of glaciology, notably glacier hydrology, debris entrainment and transfer, landform development, microbiological investigations, and in the interpretation of glacier-like features on Mars.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 3","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2021RG000743","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5822648","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}
引用次数: 28
Deep Learning for Geophysics: Current and Future Trends 地球物理学的深度学习:当前和未来趋势
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-06-03 DOI: 10.1029/2021RG000742
Siwei Yu, Jianwei Ma

Recently deep learning (DL), as a new data-driven technique compared to conventional approaches, has attracted increasing attention in geophysical community, resulting in many opportunities and challenges. DL was proven to have the potential to predict complex system states accurately and relieve the “curse of dimensionality” in large temporal and spatial geophysical applications. We address the basic concepts, state-of-the-art literature, and future trends by reviewing DL approaches in various geosciences scenarios. Exploration geophysics, earthquakes, and remote sensing are the main focuses. More applications, including Earth structure, water resources, atmospheric science, and space science, are also reviewed. Additionally, the difficulties of applying DL in the geophysical community are discussed. The trends of DL in geophysics in recent years are analyzed. Several promising directions are provided for future research involving DL in geophysics, such as unsupervised learning, transfer learning, multimodal DL, federated learning, uncertainty estimation, and active learning. A coding tutorial and a summary of tips for rapidly exploring DL are presented for beginners and interested readers of geophysics.

近年来,深度学习作为一种新的数据驱动技术,越来越受到地球物理学界的关注,同时也带来了许多机遇和挑战。深度学习被证明具有准确预测复杂系统状态的潜力,并缓解了大时空地球物理应用中的“维度诅咒”。我们通过回顾各种地球科学场景下的深度学习方法来解决基本概念、最新文献和未来趋势。勘探、地球物理、地震和遥感是主要的重点。更多的应用,包括地球结构,水资源,大气科学和空间科学也进行了综述。此外,还讨论了在地球物理领域应用DL的困难。分析了近年来地球物理中深度学习的发展趋势。提出了未来地球物理学中涉及深度学习的研究方向,如无监督学习、迁移学习、多模态深度学习、联邦学习、不确定性估计和主动学习。编码教程和快速探索DL提示的总结是为初学者和地球物理学感兴趣的读者提出的。
{"title":"Deep Learning for Geophysics: Current and Future Trends","authors":"Siwei Yu,&nbsp;Jianwei Ma","doi":"10.1029/2021RG000742","DOIUrl":"https://doi.org/10.1029/2021RG000742","url":null,"abstract":"<p>Recently deep learning (DL), as a new data-driven technique compared to conventional approaches, has attracted increasing attention in geophysical community, resulting in many opportunities and challenges. DL was proven to have the potential to predict complex system states accurately and relieve the “curse of dimensionality” in large temporal and spatial geophysical applications. We address the basic concepts, state-of-the-art literature, and future trends by reviewing DL approaches in various geosciences scenarios. Exploration geophysics, earthquakes, and remote sensing are the main focuses. More applications, including Earth structure, water resources, atmospheric science, and space science, are also reviewed. Additionally, the difficulties of applying DL in the geophysical community are discussed. The trends of DL in geophysics in recent years are analyzed. Several promising directions are provided for future research involving DL in geophysics, such as unsupervised learning, transfer learning, multimodal DL, federated learning, uncertainty estimation, and active learning. A coding tutorial and a summary of tips for rapidly exploring DL are presented for beginners and interested readers of geophysics.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 3","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2021RG000742","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5683520","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}
引用次数: 113
Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics 电离层离子对磁重联和地球磁层动力学的影响
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-06-03 DOI: 10.1029/2020RG000707
S. Toledo-Redondo, M. André, N. Aunai, C. R. Chappell, J. Dargent, S. A. Fuselier, A. Glocer, D. B. Graham, S. Haaland, M. Hesse, L. M. Kistler, B. Lavraud, W. Li, T. E. Moore, P. Tenfjord, S. K. Vines

Ionospheric ions (mainly H+, He+, and O+) escape from the ionosphere and populate the Earth's magnetosphere. Their thermal energies are usually low when they first escape the ionosphere, typically a few electron volt to tens of electron volt, but they are energized in their journey through the magnetosphere. The ionospheric population is variable, and it makes significant contributions to the magnetospheric mass density in key regions where magnetic reconnection is at work. Solar wind—magnetosphere coupling occurs primarily via magnetic reconnection, a key plasma process that enables transfer of mass and energy into the near-Earth space environment. Reconnection leads to the triggering of magnetospheric storms, auroras, energetic particle precipitation and a host of other magnetospheric phenomena. Several works in the last decades have attempted to statistically quantify the amount of ionospheric plasma supplied to the magnetosphere, including the two key regions where magnetic reconnection occurs: the dayside magnetopause and the magnetotail. Recent in situ observations by the Magnetospheric Multiscale spacecraft and associated modeling have advanced our current understanding of how ionospheric ions alter the magnetic reconnection process, including its onset and efficiency. This article compiles the current understanding of the ionospheric plasma supply to the magnetosphere. It reviews both the quantification of these sources and their effects on the process of magnetic reconnection. It also provides a global description of how the ionospheric ion contribution modifies the way the solar wind couples to the Earth's magnetosphere and how these ions modify the global dynamics of the near-Earth space environment.

电离层离子(主要是H+、He+和O+)从电离层逸出,分布在地球的磁层中。当它们第一次逃离电离层时,它们的热能通常很低,通常只有几个电子伏特到几十个电子伏特,但它们在穿过磁层的过程中充满了能量。电离层人口是可变的,它对磁重联发生的关键区域的磁层质量密度有重要贡献。太阳风-磁层耦合主要通过磁重联发生,这是一个关键的等离子体过程,可以将质量和能量转移到近地空间环境中。重联导致触发磁层风暴、极光、高能粒子降水和许多其他磁层现象。在过去的几十年里,有几项工作试图统计量化提供给磁层的电离层等离子体的数量,包括发生磁重联的两个关键区域:日侧磁层顶和磁尾。最近由磁层多尺度航天器进行的原位观测和相关的建模提高了我们目前对电离层离子如何改变磁重联过程的理解,包括它的开始和效率。本文汇编了目前对电离层等离子体向磁层供应的认识。综述了这些源的量化及其对磁重联过程的影响。它还提供了电离层离子贡献如何改变太阳风与地球磁层耦合方式的全局描述,以及这些离子如何改变近地空间环境的全局动态。
{"title":"Impacts of Ionospheric Ions on Magnetic Reconnection and Earth's Magnetosphere Dynamics","authors":"S. Toledo-Redondo,&nbsp;M. André,&nbsp;N. Aunai,&nbsp;C. R. Chappell,&nbsp;J. Dargent,&nbsp;S. A. Fuselier,&nbsp;A. Glocer,&nbsp;D. B. Graham,&nbsp;S. Haaland,&nbsp;M. Hesse,&nbsp;L. M. Kistler,&nbsp;B. Lavraud,&nbsp;W. Li,&nbsp;T. E. Moore,&nbsp;P. Tenfjord,&nbsp;S. K. Vines","doi":"10.1029/2020RG000707","DOIUrl":"https://doi.org/10.1029/2020RG000707","url":null,"abstract":"<p>Ionospheric ions (mainly H<sup>+</sup>, He<sup>+</sup>, and O<sup>+</sup>) escape from the ionosphere and populate the Earth's magnetosphere. Their thermal energies are usually low when they first escape the ionosphere, typically a few electron volt to tens of electron volt, but they are energized in their journey through the magnetosphere. The ionospheric population is variable, and it makes significant contributions to the magnetospheric mass density in key regions where magnetic reconnection is at work. Solar wind—magnetosphere coupling occurs primarily via magnetic reconnection, a key plasma process that enables transfer of mass and energy into the near-Earth space environment. Reconnection leads to the triggering of magnetospheric storms, auroras, energetic particle precipitation and a host of other magnetospheric phenomena. Several works in the last decades have attempted to statistically quantify the amount of ionospheric plasma supplied to the magnetosphere, including the two key regions where magnetic reconnection occurs: the dayside magnetopause and the magnetotail. Recent in situ observations by the Magnetospheric Multiscale spacecraft and associated modeling have advanced our current understanding of how ionospheric ions alter the magnetic reconnection process, including its onset and efficiency. This article compiles the current understanding of the ionospheric plasma supply to the magnetosphere. It reviews both the quantification of these sources and their effects on the process of magnetic reconnection. It also provides a global description of how the ionospheric ion contribution modifies the way the solar wind couples to the Earth's magnetosphere and how these ions modify the global dynamics of the near-Earth space environment.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 3","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000707","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6059199","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}
引用次数: 23
On the Cause of the Mid-Pleistocene Transition 论中更新世过渡的成因
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-05-28 DOI: 10.1029/2020RG000727
C. J. Berends, P. K?hler, L. J. Lourens, R. S. W. van de Wal

The Mid-Pleistocene Transition (MPT), where the Pleistocene glacial cycles changed from 41 to ∼100 kyr periodicity, is one of the most intriguing unsolved issues in the field of paleoclimatology. Over the course of over four decades of research, several different physical mechanisms have been proposed to explain the MPT, involving non-linear feedbacks between ice sheets and the global climate, the solid Earth, ocean circulation, and the carbon cycle. Here, we review these different mechanisms, comparing how each of them relates to the others, and to the currently available observational evidence. Based on this discussion, we identify the most important gaps in our current understanding of the MPT. We discuss how new model experiments, which focus on the quantitative differences between the different physical mechanisms, could help fill these gaps. The results of those experiments could help interpret available proxy evidence, as well as new evidence that is expected to become available.

中更新世过渡(MPT)是古气候学领域中最引人注目的未解决问题之一,更新世冰川旋回周期由41 ~ 100 kyr转变而来。在四十多年的研究过程中,已经提出了几种不同的物理机制来解释MPT,包括冰盖与全球气候、固体地球、海洋环流和碳循环之间的非线性反馈。在这里,我们回顾了这些不同的机制,比较了它们之间的关系,以及目前可用的观察证据。基于这一讨论,我们确定了我们目前对MPT的理解中最重要的差距。我们讨论了新的模型实验,其重点是不同物理机制之间的定量差异,可以帮助填补这些空白。这些实验的结果可以帮助解释现有的替代证据,以及有望获得的新证据。
{"title":"On the Cause of the Mid-Pleistocene Transition","authors":"C. J. Berends,&nbsp;P. K?hler,&nbsp;L. J. Lourens,&nbsp;R. S. W. van de Wal","doi":"10.1029/2020RG000727","DOIUrl":"https://doi.org/10.1029/2020RG000727","url":null,"abstract":"<p>The Mid-Pleistocene Transition (MPT), where the Pleistocene glacial cycles changed from 41 to ∼100 kyr periodicity, is one of the most intriguing unsolved issues in the field of paleoclimatology. Over the course of over four decades of research, several different physical mechanisms have been proposed to explain the MPT, involving non-linear feedbacks between ice sheets and the global climate, the solid Earth, ocean circulation, and the carbon cycle. Here, we review these different mechanisms, comparing how each of them relates to the others, and to the currently available observational evidence. Based on this discussion, we identify the most important gaps in our current understanding of the MPT. We discuss how new model experiments, which focus on the quantitative differences between the different physical mechanisms, could help fill these gaps. The results of those experiments could help interpret available proxy evidence, as well as new evidence that is expected to become available.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000727","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5760815","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}
引用次数: 27
The Scientific Legacy of NASA’s Operation IceBridge 美国宇航局冰桥行动的科学遗产
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-05-03 DOI: 10.1029/2020RG000712
Joseph A. MacGregor, Linette N. Boisvert, Brooke Medley, Alek A. Petty, Jeremy P. Harbeck, Robin E. Bell, J. Bryan Blair, Edward Blanchard-Wrigglesworth, Ellen M. Buckley, Michael S. Christoffersen, James R. Cochran, Beáta M. Csathó, Eugenia L. De Marco, RoseAnne T. Dominguez, Mark A. Fahnestock, Sinéad L. Farrell, S. Prasad Gogineni, Jamin S. Greenbaum, Christy M. Hansen, Michelle A. Hofton, John W. Holt, Kenneth C. Jezek, Lora S. Koenig, Nathan T. Kurtz, Ronald Kwok, Christopher F. Larsen, Carlton J. Leuschen, Caitlin D. Locke, Serdar S. Manizade, Seelye Martin, Thomas A. Neumann, Sophie M.J. Nowicki, John D. Paden, Jacqueline A. Richter-Menge, Eric J. Rignot, Fernando Rodríguez-Morales, Matthew R. Siegfried, Benjamin E. Smith, John G. Sonntag, Michael Studinger, Kirsty J. Tinto, Martin Truffer, Thomas P. Wagner, John E. Woods, Duncan A. Young, James K. Yungel

The National Aeronautics and Space Administration (NASA)’s Operation IceBridge (OIB) was a 13-year (2009–2021) airborne mission to survey land and sea ice across the Arctic, Antarctic, and Alaska. Here, we review OIB’s goals, instruments, campaigns, key scientific results, and implications for future investigations of the cryosphere. OIB’s primary goal was to use airborne laser altimetry to bridge the gap in fine-resolution elevation measurements of ice from space between the conclusion of NASA’s Ice, Cloud, and land Elevation Satellite (ICESat; 2003–2009) and its follow-on, ICESat-2 (launched 2018). Additional scientific requirements were intended to contextualize observed elevation changes using a multisensor suite of radar sounders, gravimeters, magnetometers, and cameras. Using 15 different aircraft, OIB conducted 968 science flights, of which 42% were repeat surveys of land ice, 42% were surveys of previously unmapped terrain across the Greenland and Antarctic ice sheets, Arctic ice caps, and Alaskan glaciers, and 16% were surveys of sea ice. The combination of an expansive instrument suite and breadth of surveys enabled numerous fundamental advances in our understanding of the Earth’s cryosphere. For land ice, OIB dramatically improved knowledge of interannual outlet-glacier variability, ice-sheet, and outlet-glacier thicknesses, snowfall rates on ice sheets, fjord and sub-ice-shelf bathymetry, and ice-sheet hydrology. Unanticipated discoveries included a reliable method for constraining the thickness within difficult-to-sound incised troughs beneath ice sheets, the extent of the firn aquifer within the Greenland Ice Sheet, the vulnerability of many Greenland and Antarctic outlet glaciers to ocean-driven melting at their grounding zones, and the dominance of surface-melt-driven mass loss of Alaskan glaciers. For sea ice, OIB significantly advanced our understanding of spatiotemporal variability in sea ice freeboard and its snow cover, especially through combined analysis of fine-resolution altimetry, visible imagery, and snow radar measurements of the overlying snow thickness. Such analyses led to the unanticipated discovery of an interdecadal decrease in snow thickness on Arctic sea ice and numerous opportunities to validate sea ice freeboards from satellite radar altimetry. While many of its data sets have yet to be fully explored, OIB’s scientific legacy has already demonstrated the value of sustained investment in reliable airborne platforms, airborne instrument development, interagency and international collaboration, and open and rapid data access to advance our understanding of Earth’s remote polar regions and their role in the Earth system.

美国国家航空航天局(NASA)的冰桥行动(OIB)是一项为期13年(2009-2021)的机载任务,旨在调查北极、南极和阿拉斯加的陆地和海冰。在这里,我们回顾了OIB的目标、仪器、活动、关键科学成果以及对未来冰冻圈研究的影响。OIB的主要目标是利用机载激光测高来弥补NASA的冰、云和陆地高程卫星(ICESat;2003-2009年)及其后续卫星ICESat-2(2018年发射)。额外的科学要求旨在利用雷达测深仪、重力仪、磁力计和相机的多传感器套件来分析观测到的高程变化。OIB使用15架不同的飞机进行了968次科学飞行,其中42%是对陆地冰的重复调查,42%是对格陵兰岛和南极冰盖、北极冰盖和阿拉斯加冰川等以前未绘制的地形的调查,16%是对海冰的调查。一套庞大的仪器和广泛的调查使我们对地球冰冻圈的了解取得了许多根本性的进展。对于陆冰,OIB极大地提高了对年际出口-冰川变化、冰盖和出口-冰川厚度、冰盖降雪率、峡湾和亚冰架测深以及冰盖水文的认识。意料之外的发现包括一种可靠的方法,用于限制冰盖下难以听清的切割槽的厚度,格陵兰冰盖内坚硬的含水层的范围,许多格陵兰和南极出口冰川在其接地区受到海洋驱动融化的脆弱性,以及阿拉斯加冰川表面融化驱动的质量损失占主导地位。对于海冰,OIB显著提高了我们对海冰干舷及其积雪的时空变化的理解,特别是通过对上覆雪厚度的精细分辨率测高、可见光图像和雪雷达测量的综合分析。这样的分析导致了意想不到的发现,即北极海冰上积雪厚度的年代际减少,以及通过卫星雷达测高验证海冰干舷的许多机会。虽然其许多数据集尚未得到充分探索,但OIB的科学遗产已经证明了在可靠的机载平台,机载仪器开发,机构间和国际合作以及开放和快速的数据访问方面持续投资的价值,以促进我们对地球偏远极地地区及其在地球系统中的作用的理解。
{"title":"The Scientific Legacy of NASA’s Operation IceBridge","authors":"Joseph A. MacGregor,&nbsp;Linette N. Boisvert,&nbsp;Brooke Medley,&nbsp;Alek A. Petty,&nbsp;Jeremy P. Harbeck,&nbsp;Robin E. Bell,&nbsp;J. Bryan Blair,&nbsp;Edward Blanchard-Wrigglesworth,&nbsp;Ellen M. Buckley,&nbsp;Michael S. Christoffersen,&nbsp;James R. Cochran,&nbsp;Beáta M. Csathó,&nbsp;Eugenia L. De Marco,&nbsp;RoseAnne T. Dominguez,&nbsp;Mark A. Fahnestock,&nbsp;Sinéad L. Farrell,&nbsp;S. Prasad Gogineni,&nbsp;Jamin S. Greenbaum,&nbsp;Christy M. Hansen,&nbsp;Michelle A. Hofton,&nbsp;John W. Holt,&nbsp;Kenneth C. Jezek,&nbsp;Lora S. Koenig,&nbsp;Nathan T. Kurtz,&nbsp;Ronald Kwok,&nbsp;Christopher F. Larsen,&nbsp;Carlton J. Leuschen,&nbsp;Caitlin D. Locke,&nbsp;Serdar S. Manizade,&nbsp;Seelye Martin,&nbsp;Thomas A. Neumann,&nbsp;Sophie M.J. Nowicki,&nbsp;John D. Paden,&nbsp;Jacqueline A. Richter-Menge,&nbsp;Eric J. Rignot,&nbsp;Fernando Rodríguez-Morales,&nbsp;Matthew R. Siegfried,&nbsp;Benjamin E. Smith,&nbsp;John G. Sonntag,&nbsp;Michael Studinger,&nbsp;Kirsty J. Tinto,&nbsp;Martin Truffer,&nbsp;Thomas P. Wagner,&nbsp;John E. Woods,&nbsp;Duncan A. Young,&nbsp;James K. Yungel","doi":"10.1029/2020RG000712","DOIUrl":"https://doi.org/10.1029/2020RG000712","url":null,"abstract":"<p>The National Aeronautics and Space Administration (NASA)’s Operation IceBridge (OIB) was a 13-year (2009–2021) airborne mission to survey land and sea ice across the Arctic, Antarctic, and Alaska. Here, we review OIB’s goals, instruments, campaigns, key scientific results, and implications for future investigations of the cryosphere. OIB’s primary goal was to use airborne laser altimetry to bridge the gap in fine-resolution elevation measurements of ice from space between the conclusion of NASA’s Ice, Cloud, and land Elevation Satellite (ICESat; 2003–2009) and its follow-on, ICESat-2 (launched 2018). Additional scientific requirements were intended to contextualize observed elevation changes using a multisensor suite of radar sounders, gravimeters, magnetometers, and cameras. Using 15 different aircraft, OIB conducted 968 science flights, of which 42% were repeat surveys of land ice, 42% were surveys of previously unmapped terrain across the Greenland and Antarctic ice sheets, Arctic ice caps, and Alaskan glaciers, and 16% were surveys of sea ice. The combination of an expansive instrument suite and breadth of surveys enabled numerous fundamental advances in our understanding of the Earth’s cryosphere. For land ice, OIB dramatically improved knowledge of interannual outlet-glacier variability, ice-sheet, and outlet-glacier thicknesses, snowfall rates on ice sheets, fjord and sub-ice-shelf bathymetry, and ice-sheet hydrology. Unanticipated discoveries included a reliable method for constraining the thickness within difficult-to-sound incised troughs beneath ice sheets, the extent of the firn aquifer within the Greenland Ice Sheet, the vulnerability of many Greenland and Antarctic outlet glaciers to ocean-driven melting at their grounding zones, and the dominance of surface-melt-driven mass loss of Alaskan glaciers. For sea ice, OIB significantly advanced our understanding of spatiotemporal variability in sea ice freeboard and its snow cover, especially through combined analysis of fine-resolution altimetry, visible imagery, and snow radar measurements of the overlying snow thickness. Such analyses led to the unanticipated discovery of an interdecadal decrease in snow thickness on Arctic sea ice and numerous opportunities to validate sea ice freeboards from satellite radar altimetry. While many of its data sets have yet to be fully explored, OIB’s scientific legacy has already demonstrated the value of sustained investment in reliable airborne platforms, airborne instrument development, interagency and international collaboration, and open and rapid data access to advance our understanding of Earth’s remote polar regions and their role in the Earth system.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000712","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5687515","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}
引用次数: 46
A Decade of Lessons Learned from the 2011 Tohoku-Oki Earthquake 2011年日本东北大地震的十年教训
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-04-23 DOI: 10.1029/2020RG000713
N. Uchida, R. Bürgmann

The 2011 Mw 9.0 Tohoku-oki earthquake is one of the world's best-recorded ruptures. In the aftermath of this devastating event, it is important to learn from the complete record. We describe the state of knowledge of the megathrust earthquake generation process before the earthquake, and what has been learned in the decade since the historic event. Prior to 2011, there were a number of studies suggesting the potential of a great megathrust earthquake in NE Japan from geodesy, geology, seismology, geomorphology, and paleoseismology, but results from each field were not enough to enable a consensus assessment of the hazard. A transient unfastening of interplate coupling and increased seismicity were recognized before the earthquake, but did not lead to alerts. Since the mainshock, follow-up studies have (1) documented that the rupture occurred in an area with a large interplate slip deficit, (2) established large near-trench coseismic slip, (3) examined structural anomalies and fault-zone materials correlated with the coseismic slip, (4) clarified the historical and paleoseismic recurrence of M∼9 earthquakes, and (5) identified various kinds of possible precursors. The studies have also illuminated the heterogeneous distribution of coseismic rupture, aftershocks, slow earthquakes and aseismic afterslip, and the enduring viscoelastic response, which together make up the complex megathrust earthquake cycle. Given these scientific advances, the enhanced seismic hazard of an impending great earthquake can now be more accurately established, although we do not believe such an event could be predicted with confidence.

2011年发生的9.0级日本东北大地震是世界上记录最多的地震之一。在这一毁灭性事件发生后,重要的是要从完整的记录中学习。我们描述了地震发生前对大逆冲地震发生过程的认识状况,以及地震发生后十年来对大逆冲地震的认识。在2011年之前,从大地测量学、地质学、地震学、地貌学和古地震学等方面进行了大量研究,表明日本东北部有可能发生大逆冲地震,但每个领域的结果都不足以对危险性进行共识评估。在地震发生前,人们已经认识到板间耦合的瞬态松开和地震活动性的增加,但没有引起警报。自主震以来,后续研究(1)记录了破裂发生在一个具有较大板间滑动亏损的地区,(2)建立了较大的近海沟同震滑动,(3)检查了与同震滑动相关的结构异常和断裂带物质,(4)阐明了M ~ 9地震的历史和古地震复发,(5)确定了各种可能的前兆。研究还揭示了同震破裂、余震、慢震和地震余震的非均匀分布,以及持久的粘弹性反应,这些共同构成了复杂的大逆冲地震旋回。鉴于这些科学进步,现在可以更准确地确定即将发生的大地震的地震危险性,尽管我们不相信这样的事件可以有把握地预测出来。
{"title":"A Decade of Lessons Learned from the 2011 Tohoku-Oki Earthquake","authors":"N. Uchida,&nbsp;R. Bürgmann","doi":"10.1029/2020RG000713","DOIUrl":"https://doi.org/10.1029/2020RG000713","url":null,"abstract":"<p>The 2011 Mw 9.0 Tohoku-oki earthquake is one of the world's best-recorded ruptures. In the aftermath of this devastating event, it is important to learn from the complete record. We describe the state of knowledge of the megathrust earthquake generation process before the earthquake, and what has been learned in the decade since the historic event. Prior to 2011, there were a number of studies suggesting the potential of a great megathrust earthquake in NE Japan from geodesy, geology, seismology, geomorphology, and paleoseismology, but results from each field were not enough to enable a consensus assessment of the hazard. A transient unfastening of interplate coupling and increased seismicity were recognized before the earthquake, but did not lead to alerts. Since the mainshock, follow-up studies have (1) documented that the rupture occurred in an area with a large interplate slip deficit, (2) established large near-trench coseismic slip, (3) examined structural anomalies and fault-zone materials correlated with the coseismic slip, (4) clarified the historical and paleoseismic recurrence of M∼9 earthquakes, and (5) identified various kinds of possible precursors. The studies have also illuminated the heterogeneous distribution of coseismic rupture, aftershocks, slow earthquakes and aseismic afterslip, and the enduring viscoelastic response, which together make up the complex megathrust earthquake cycle. Given these scientific advances, the enhanced seismic hazard of an impending great earthquake can now be more accurately established, although we do not believe such an event could be predicted with confidence.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5784250","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}
引用次数: 30
Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion 极地平流层云:卫星观测、过程和臭氧消耗的作用
IF 25.2 1区 地球科学 Q1 Earth and Planetary Sciences Pub Date : 2021-04-04 DOI: 10.1029/2020RG000702
Ines Tritscher, Michael C. Pitts, Lamont R. Poole, Simon P. Alexander, Francesco Cairo, Martyn P. Chipperfield, Jens-Uwe Groo?, Michael H?pfner, Alyn Lambert, Beiping Luo, Sergey Molleker, Andrew Orr, Ross Salawitch, Marcel Snels, Reinhold Spang, Wolfgang Woiwode, Thomas Peter

Polar stratospheric clouds (PSCs) play important roles in stratospheric ozone depletion during winter and spring at high latitudes (e.g., the Antarctic ozone hole). PSC particles provide sites for heterogeneous reactions that convert stable chlorine reservoir species to radicals that destroy ozone catalytically. PSCs also prolong ozone depletion by delaying chlorine deactivation through the removal of gas-phase HNO3 and H2O by sedimentation of large nitric acid trihydrate (NAT) and ice particles. Contemporary observations by the spaceborne instruments Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), Microwave Limb Sounder (MLS), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) have provided an unprecedented polar vortex-wide climatological view of PSC occurrence and composition in both hemispheres. These data have spurred advances in our understanding of PSC formation and related dynamical processes, especially the firm evidence of widespread heterogeneous nucleation of both NAT and ice PSC particles, perhaps on nuclei of meteoritic origin. Heterogeneous chlorine activation appears to be well understood. Reaction coefficients on/in liquid droplets have been measured accurately, and while uncertainties remain for reactions on solid NAT and ice particles, they are considered relatively unimportant since under most conditions chlorine activation occurs on/in liquid droplets. There have been notable advances in the ability of chemical transport and chemistry-climate models to reproduce PSC temporal/spatial distributions and composition observed from space. Continued spaceborne PSC observations will facilitate further improvements in the representation of PSC processes in global models and enable more accurate projections of the evolution of polar ozone and the global ozone layer as climate changes.

极地平流层云(PSCs)在冬季和春季高纬度地区(如南极臭氧空洞)的平流层臭氧消耗中起重要作用。PSC粒子为非均相反应提供了场所,这些反应将稳定的氯储层物质转化为催化破坏臭氧的自由基。PSCs还通过沉淀大的三水合物硝酸(NAT)和冰粒去除气相HNO3和H2O,从而延缓氯的失活,从而延长臭氧消耗。通过星载仪器迈克尔逊被动大气探测干涉仪(MIPAS)、微波边缘测深仪(MLS)和正交偏振云气溶胶激光雷达(CALIOP)的当代观测,提供了一个前所未有的极地涡旋范围内PSC发生和组成的气候学视图。这些数据促进了我们对PSC形成和相关动力学过程的理解,特别是NAT和冰PSC粒子广泛非均质成核的确凿证据,可能是陨石核的起源。非均相氯活化似乎已被很好地理解。液滴上/液滴内的反应系数已经得到了精确的测量,虽然固体NAT和冰粒上的反应仍然存在不确定性,但它们被认为相对不重要,因为在大多数情况下,氯在液滴上/液滴内发生活化。在化学输运和化学-气候模式重现从空间观测到的PSC时空分布和组成的能力方面取得了显著进展。继续进行星载PSC观测将有助于进一步改进全球模式中PSC过程的表示,并能够更准确地预估极地臭氧和全球臭氧层随着气候变化的演变。
{"title":"Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion","authors":"Ines Tritscher,&nbsp;Michael C. Pitts,&nbsp;Lamont R. Poole,&nbsp;Simon P. Alexander,&nbsp;Francesco Cairo,&nbsp;Martyn P. Chipperfield,&nbsp;Jens-Uwe Groo?,&nbsp;Michael H?pfner,&nbsp;Alyn Lambert,&nbsp;Beiping Luo,&nbsp;Sergey Molleker,&nbsp;Andrew Orr,&nbsp;Ross Salawitch,&nbsp;Marcel Snels,&nbsp;Reinhold Spang,&nbsp;Wolfgang Woiwode,&nbsp;Thomas Peter","doi":"10.1029/2020RG000702","DOIUrl":"https://doi.org/10.1029/2020RG000702","url":null,"abstract":"<p>Polar stratospheric clouds (PSCs) play important roles in stratospheric ozone depletion during winter and spring at high latitudes (e.g., the Antarctic ozone hole). PSC particles provide sites for heterogeneous reactions that convert stable chlorine reservoir species to radicals that destroy ozone catalytically. PSCs also prolong ozone depletion by delaying chlorine deactivation through the removal of gas-phase HNO<sub>3</sub> and H<sub>2</sub>O by sedimentation of large nitric acid trihydrate (NAT) and ice particles. Contemporary observations by the spaceborne instruments Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), Microwave Limb Sounder (MLS), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) have provided an unprecedented polar vortex-wide climatological view of PSC occurrence and composition in both hemispheres. These data have spurred advances in our understanding of PSC formation and related dynamical processes, especially the firm evidence of widespread heterogeneous nucleation of both NAT and ice PSC particles, perhaps on nuclei of meteoritic origin. Heterogeneous chlorine activation appears to be well understood. Reaction coefficients on/in liquid droplets have been measured accurately, and while uncertainties remain for reactions on solid NAT and ice particles, they are considered relatively unimportant since under most conditions chlorine activation occurs on/in liquid droplets. There have been notable advances in the ability of chemical transport and chemistry-climate models to reproduce PSC temporal/spatial distributions and composition observed from space. Continued spaceborne PSC observations will facilitate further improvements in the representation of PSC processes in global models and enable more accurate projections of the evolution of polar ozone and the global ozone layer as climate changes.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000702","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6057654","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}
引用次数: 52
期刊
Reviews of Geophysics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1