Reviews of Geophysics最新文献

{"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⁺, 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.</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}

{"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}

{"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}

{"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}

{"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 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.</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}

{"title":"Thank You to Our Peer Reviewers for 2020","authors":"Fabio Florindo,&nbsp;Annmarie G. Carlton,&nbsp;Paolo D'Odorico,&nbsp;Qingyun Duan,&nbsp;Jasper S. Halekas,&nbsp;Gesine Mollenhauer,&nbsp;Eelco J. Rohling,&nbsp;Robert G. Bingham,&nbsp;Emily E. Brodsky,&nbsp;Michel C. Crucifix,&nbsp;Andrew Gettelman,&nbsp;Alan Robock","doi":"10.1029/2021RG000741","DOIUrl":"https://doi.org/10.1029/2021RG000741","url":null,"abstract":"<p>RoG is the top-rated journal in geochemistry and geophysics (Figure 1), and it could not exist without your investment of time and effort. Your expertize ensures that the papers published in this journal meet the standards that the research community expects. We sincerely appreciate the time you spent reading and commenting on manuscripts, and we are very grateful for your willingness and readiness to serve in this role.</p><p>This is particularly the case in the year of the COVID-19 pandemic where health and medical issues have significantly disrupted the usual rhythm of our days and the whole world has needed to come to grips with a new way of working.</p><p>RoG published 24 review papers and an editorial in 2020, covering most of the AGU section topics, and for this, we were able to rely on the efforts of 82 dedicated reviewers from 16 countries, who freely donated their expertize to the journal. Many reviewers answered the call multiple times, as RoG received 110 reviews in 2020. Thank you all again for your awesome efforts, your insights, and your service on behalf of the Earth and space science community. The names of reviewers who agreed to share their names are listed below.</p><p>We look forward to a 2021 of exciting advances in the field and communicating those advances to our community and the broader public. If you have comments regarding the RoG or its peer review process, we invite you to contact the journal at <span>[email protected]</span>.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 1","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2021RG000741","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6055291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Quarter Century of Wind Spacecraft Discoveries","authors":"Lynn B. Wilson III,&nbsp;Alexandra L. Brosius,&nbsp;Natchimuthuk Gopalswamy,&nbsp;Teresa Nieves-Chinchilla,&nbsp;Adam Szabo,&nbsp;Kevin Hurley,&nbsp;Tai Phan,&nbsp;Justin C. Kasper,&nbsp;Noé Lugaz,&nbsp;Ian G. Richardson,&nbsp;Christopher H. K. Chen,&nbsp;Daniel Verscharen,&nbsp;Robert T. Wicks,&nbsp;Jason M. TenBarge","doi":"10.1029/2020RG000714","DOIUrl":"https://doi.org/10.1029/2020RG000714","url":null,"abstract":"<p>The <i>Wind</i> spacecraft, launched on November 1, 1994, is a critical element in NASA’s Heliophysics System Observatory (HSO)—a fleet of spacecraft created to understand the dynamics of the Sun-Earth system. The combination of its longevity (&gt;25 years in service), its diverse complement of instrumentation, and high resolution and accurate measurements has led to it becoming the “standard candle” of solar wind measurements. <i>Wind</i> has over 55 selectable public data products with over ∼1,100 total data variables (including OMNI data products) on SPDF/CDAWeb alone. These data have led to paradigm shifting results in studies of statistical solar wind trends, magnetic reconnection, large-scale solar wind structures, kinetic physics, electromagnetic turbulence, the Van Allen radiation belts, coronal mass ejection topology, interplanetary and interstellar dust, the lunar wake, solar radio bursts, solar energetic particles, and extreme astrophysical phenomena such as gamma-ray bursts. This review introduces the mission and instrument suites then discusses examples of the contributions by <i>Wind</i> to these scientific topics that emphasize its importance to both the fields of heliophysics and astrophysics.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000714","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5733683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Integrative Conceptualization of Floodplain Storage","authors":"Ellen Wohl","doi":"10.1029/2020RG000724","DOIUrl":"https://doi.org/10.1029/2020RG000724","url":null,"abstract":"<p>Floodplains perform diverse functions, including attenuation of fluxes of water, solutes, and particulate material. Critical details of floodplain storage including magnitude, duration, and spatial distribution are strongly influenced by floodplain biogeochemical processes and biotic communities. Floodplain storage of diverse materials can be conceptualized in the form of a budget that quantifies inputs, outputs, and storage within the floodplain control volume. The floodplain control volume is here defined as bounded on the inner edges by the banks of the active channel(s), on the outer edges by the limit of periodic flooding and the deposition of fluvially transported sediment, on the underside by the extent of hyporheic exchange flows and the floodplain aquifer, and on the upper side by the upper elevation of living vegetation. Fluxes within the floodplain control volume can also change the location, characteristics, and residence time of material in storage. Fluxes, residence time, and quantities of material stored in floodplains can be measured directly; inferred from diverse types of remotely sensed data; or quantitatively estimated using numerical models. Human activities can modify floodplain storage by: hydrologically and/or geomorphically disconnecting channels and floodplains; altering fluxes of water and sediment to the river corridor; and obliterating floodplains through alluvial mining or urbanization. Floodplain restoration can focus on enlarging the functional floodplain, reconnecting the channel and floodplain, restoring natural regimes of water, sediment, and/or large wood, or enhancing the spatial heterogeneity of the channel and floodplain. Each form of floodplain restoration can increase floodplain storage and resilience to disturbances.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000724","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6175565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Properties of Annually Laminated Stalagmites-A Global Synthesis","authors":"Andy Baker,&nbsp;Gregoire Mariethoz,&nbsp;Laia Comas-Bru,&nbsp;Andreas Hartmann,&nbsp;Silvia Frisia,&nbsp;Andrea Borsato,&nbsp;Pauline C. Treble,&nbsp;Asfawossen Asrat","doi":"10.1029/2020RG000722","DOIUrl":"https://doi.org/10.1029/2020RG000722","url":null,"abstract":"<p>Annually laminated speleothems have the potential to provide information on high-frequency climate variability and, simultaneously, provide good chronological constraints. However, there are distinct types of speleothem annual laminae, from physical to chemical, and a common mechanism that links their formation has yet to be found. Here, we analyzed annually laminated stalagmites from 23 caves and 6 continents with the aim to find if there are common mechanisms underlying their development. Annually laminated stalagmites are least common in arid and semiarid climates, and most common in regions with a seasonality of precipitation. At a global scale, we observe faster growth rates with increasing mean annual temperature and decreasing latitude. Changepoints in average growth rates are infrequent and age-depth relationships demonstrate that growth rates can be approximated to be constant. In general, annually laminated stalagmites are characterized by centennial-scale stability in calcite precipitation due to a sufficiently large and well-mixed water source, a time series spectrum showing first-order autoregression due to mixing of stored water and annual recharged water, and an inter-annual flickering of growth acceleration, bringing growth rates back to the long-term mean. Climate forcing of growth rate variations is observed where a multi-year climate signal is strong enough to be the dominant control on calcite growth rate variability, such that it retains a climate imprint after smoothing of this signal by mixing of stored water. In contrast, long-term constant growth rate of laminated stalagmites adds further robustness to their unparalleled capacity to improve accuracy of chronology building.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2020RG000722","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6050872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anthropogenic Drought: Definition, Challenges, and Opportunities","authors":"Amir AghaKouchak,&nbsp;Ali Mirchi,&nbsp;Kaveh Madani,&nbsp;Giuliano Di Baldassarre,&nbsp;Ali Nazemi,&nbsp;Aneseh Alborzi,&nbsp;Hassan Anjileli,&nbsp;Marzi Azarderakhsh,&nbsp;Felicia Chiang,&nbsp;Elmira Hassanzadeh,&nbsp;Laurie S. Huning,&nbsp;Iman Mallakpour,&nbsp;Alexandre Martinez,&nbsp;Omid Mazdiyasni,&nbsp;Hamed Moftakhari,&nbsp;Hamid Norouzi,&nbsp;Mojtaba Sadegh,&nbsp;Dalal Sadeqi,&nbsp;Anne F. Van Loon,&nbsp;Niko Wanders","doi":"10.1029/2019RG000683","DOIUrl":"https://doi.org/10.1029/2019RG000683","url":null,"abstract":"<p>Traditional, mainstream definitions of drought describe it as deficit in water-related variables or water-dependent activities (e.g., precipitation, soil moisture, surface and groundwater storage, and irrigation) due to natural variabilities that are out of the control of local decision-makers. Here, we argue that within coupled human-water systems, drought must be defined and understood as a <i>process</i> as opposed to a <i>product</i> to help better frame and describe the complex and interrelated dynamics of both natural and human-induced changes that define <i>anthropogenic drought</i> as a compound multidimensional and multiscale phenomenon, governed by the combination of natural water variability, climate change, human decisions and activities, and altered micro-climate conditions due to changes in land and water management. This definition considers the full spectrum of dynamic feedbacks and processes (e.g., land-atmosphere interactions and water and energy balance) within human-nature systems that drive the development of <i>anthropogenic drought</i>. This process magnifies the water supply demand gap and can lead to water bankruptcy, which will become more rampant around the globe in the coming decades due to continuously growing water demands under compounding effects of climate change and global environmental degradation. This challenge has de facto implications for both short-term and long-term water resources planning and management, water governance, and policymaking. Herein, after a brief overview of the anthropogenic drought concept and its examples, we discuss existing research gaps and opportunities for better understanding, modeling, and management of this phenomenon.</p>","PeriodicalId":21177,"journal":{"name":"Reviews of Geophysics","volume":"59 2","pages":""},"PeriodicalIF":25.2,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2019RG000683","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"6081646","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}