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Jean Roger, Bernard Pelletier, Maxime Duphil, Jérôme Lefèvre, Jérôme Aucan, Pierre Lebellegard, Bruce Thomas, Céline Bachelier, David Varillon |
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The Mw 7.5 Tadine (Maré, Loyalty Is.) earthquake and related tsunami of December 5, 2018: implications for tsunami hazard assessment in New Caledonia |
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2021 |
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Natural Hazards and Earth System Sciences Discussions |
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1-25 |
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On The 5th Of December 2018, A Magnitude Mw 7.5 Earthquake Occurred Southeast Of Maré, An Island Of The Loyalty Archipelago, New Caledonia. This Earthquake Is Located At The Junction Between The Plunging Loyalty Ridge And The Southernmost Vanuatu Arc, In A Tectonically Very Active Area Regularly Subjected To Strong Seismic Crises And Events Higher Than Magnitude 7 And Up To 8. Widely Felt In New Caledonia It Has Been Immediately Followed By A Tsunami Warning, Confirmed Shortly After By A First Wave Arrival At The Loyalty Islands Tide Gauges (Maré And Lifou), Then Along The East Coast Of Grande Terre Of New Caledonia And In Several Islands Of The Vanuatu Archipelago. Seafloor Initial Deformation Linked To Tsunami Generation Has Been Modeled With Most Numerical Code Using Earthquake Parameters Available From Seismic Observatories. Then The Wave Propagation Has Been Modeled Using Schism, Another Modelling Code Solving The Shallow Water Equations On An Unstructured Grid Based On A New Regional Dem Of ~180 M Resolution And Allowing Refinement In Many Critical Areas. Finally, The Results Have Been Compared To Tide Gauge Records, Field Observations And Testimonials From 2018. The Arrival Times, Wave Amplitude And Polarities Present Good Similarities, Especially In Far-field Locations (Hienghène, Port-vila And Poindimié). Maximum Wave Heights And Energy Maps For Two Different Scenarios Highlight The Fact That The Orientation Of The Source (Strike Of The Rupture) Played An Important Role, Focusing The Maximum Energy Path Of The Tsunami South Of Grande-terre And The Isle Of Pines. However, Both Scenarios Indicate Similar Propagation Toward Aneityum, Vanuatu Southernmost Island, The Bathymetry Acting Like A Waveguide. This Study Has A Significant Implication In Tsunami Hazard Mitigation In New Caledonia As It Helps To Validate The Modelling Code And Process Used To Prepare A Scenarios Database For Warning And Coastal Evacuation. |
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8019 |
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Maria Federica Marcucci, Igino Coco, Stefano Massetti, Alessio Pignalberi, Victoriya Forsythe, Michael Pezzopane, Alexander Koustov, Simona Longo, David Biondi, Enrico Simeoli, Giuseppe Consolini, Monica Laurenza, Aurélie Marchaudon, Andrea Satta, Alessandro Cirioni, Angelo De Simone, Angelo Olivieri, Alessandro Baù, Alberto Salvati |
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Echo occurrence in the southern polar ionosphere for the SuperDARN Dome C East and Dome C North radars |
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2021 |
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Polar Science |
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28 |
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100684 |
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Echo occurrence IRI model Polar cap radars Ray-tracing |
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In this paper, echo occurrence rates for the Dome C East (DCE) and the new Dome C North (DCN) radars are studied. We report the ionospheric and ground scatter echo occurrence rates for selected periods around equinoxes and solstices in the final part of the solar cycle XXIV. The occurrence maps built in Altitude Adjusted Corrected Geomagnetic latitude and Magnetic Local Time coordinates show peculiar patterns highly variable with season. The comparisons of the radar observations with the International Reference Ionosphere model electron density and with ray tracing simulations allow us to explain the major features of observed patterns in terms of electron density variations. The study shows the great potential of the DCE and DCN radar combination to the Super Dual Auroral Radar Network (SuperDARN) convection mapping in terms of monitoring key regions of the high-latitude ionosphere critical for understanding of the magnetospheric dynamics. |
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1873-9652 |
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8020 |
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Matthias Macé, Camille Richeval, Liubomira Romanova, Patrice Gérard, Sylvie Duchesne, Catherine Cannet, Irina Boyarskikh, Annie Gérault, Vincent Zvénigorosky, Darya Nikolaeva, Charles Stepanoff, Delphine Allorge, Michele Debrenne, Bertrand Ludes, Anatoly Alexeev, Jean-Michel Gaulier, Eric Crubézy |
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Impact of socio-economic traditions on current tobacco and tea addictions (Siberia 17th to 20th century) |
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2021 |
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Medrxiv |
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Objective To investigate how tobacco and tea spread among virgin populations and how the first addictions have subsequently influenced the behavior of present-day populations. Design Retrospective observational study using data from frozen burials and levels of theobromine, theophylline, caffeine, nicotine, and cotinine measured in hair samples from frozen bodies of autochthonous people. Confrontation of the results with new ethnobotanical, historical and cultural data from the past and with present day epidemiological data from the same region. Setting Eastern Siberia (Yakutia) from the contact with Europeans (17th century) to the assimilation of people into Russian society (19th century). Participants 47 frozen bodies of autochthonous people from eastern Siberia and a review of present-day populations from Yakutia Intervention Levels of theobromine, theophylline, caffeine, nicotine, and cotinine were measured in hair samples. Along with the collection of cultural data associated with the bodies, potential comorbidities were investigated. Main outcome measure We combined LC-HRMS and LC-MS/MS tools for toxicological investigations in hair and we assessed the association between xenobiotic concentrations and geography using several permutation-based methods to infer the economic circuits of tobacco and tea. Comparison of the results obtained with ethno-botanical analyses allowed to identify the products from which the metabolites were derived. Results Hair levels of theobromine, theophylline and caffeine vary with the type of beverage consumed: green, black or local herbal teas. At the beginning of our study period, a few heavy consumers of tobacco were found among light or passive consumers. Tobacco-related co-morbidities began to be recorded one century after contact with Europeans. Heavy tea users were only found from the 19th century and the heaviest users of the two substances date from this century. After the first contact, teas were widely consumed as beverages and medicines but also for shamanic reasons. Economic factors, fashion and social and family contacts seem to have played a decisive role in tobacco consumption very early on. Conclusion Epidemiological characteristics of present-day Yakutia suggest that the high prevalence of smokers and tea consumers, the prevalence of female smokers and tobacco use in the north, find their origins in the diffusion phenomena of the 18th and 19th century. Behavioral evolution governed the process of substance integration and was determinant for the continuity of use of these substances over a long period of time. |
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7952 |
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Marina Renedo, David Amouroux, Céline Albert, Sylvain Bérail, Vegard S. Bråthen, Maria Gavrilo, David Grémillet, Hálfdán H. Helgason, Dariusz Jakubas, Anders Mosbech, Hallvard Strøm, Emmanuel Tessier, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort |
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Title |
Contrasting Spatial and Seasonal Trends of Methylmercury Exposure Pathways of Arctic Seabirds: Combination of Large-Scale Tracking and Stable Isotopic Approaches |
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Year |
2021 |
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Environmental Science & Technology |
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Volume |
54 |
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21 |
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13619-13629 |
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Abstract |
Despite the limited direct anthropogenic mercury (Hg) inputs in the circumpolar Arctic, elevated concentrations of methylmercury (MeHg) are accumulated in Arctic marine biota. However, the MeHg production and bioaccumulation pathways in these ecosystems have not been completely unraveled. We measured Hg concentrations and stable isotope ratios of Hg, carbon, and nitrogen in the feathers and blood of geolocator-tracked little auk Alle alle from five Arctic breeding colonies. The wide-range spatial mobility and tissue-specific Hg integration times of this planktivorous seabird allowed the exploration of their spatial (wintering quarters/breeding grounds) and seasonal (nonbreeding/breeding periods) MeHg exposures. An east-to-west increase of head feather Hg concentrations (1.74–3.48 μg·g–1) was accompanied by significant spatial trends of Hg isotope (particularly Δ199Hg: 0.96–1.13‰) and carbon isotope (δ13C: −20.6 to −19.4‰) ratios. These trends suggest a distinct mixing/proportion of MeHg sources between western North Atlantic and eastern Arctic regions. Higher Δ199Hg values (+0.4‰) in northern colonies indicate an accumulation of more photochemically impacted MeHg, supporting shallow MeHg production and bioaccumulation in high Arctic waters. The combination of seabird tissue isotopic analysis and spatial tracking helps in tracing the MeHg sources at various spatio-temporal scales. |
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0013-936X |
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8023 |
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Benjamin Merkel, Sébastien Descamps, Nigel G. Yoccoz, David Grémillet, Francis Daunt, Kjell E. Erikstad, Aleksey V. Ezhov, Mike P. Harris, Maria Gavrilo, Svein-Håkon Lorentsen, Tone K. Reiertsen, Harald Steen, Geir H. Systad, Þorkell Lindberg Þórarinsson, Sarah Wanless, Hallvard Strøm |
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Title |
Individual migration strategy fidelity but no habitat specialization in two congeneric seabirds |
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2021 |
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Journal of Biogeography |
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48 |
Issue |
2 |
Pages |
263-275 |
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guillemots light-level geolocation murres Uria aalge Uria lomvia |
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Aim In migratory species, individuals often use fixed and individual-specific migration strategies, which we term individual migration strategy fidelity (IMSF). Our goal was to test if guillemots have flexible or fixed individual migration strategies (i.e. IMSF), if this behaviour is consistent across large parts of the genus’ range and if they were philopatric to geographical sites or a habitat feature. Location North Atlantic. Taxon Uria spp. Methods We quantified consistent individual differences in inter-annual spatial distribution and habitat occupied throughout the non-breeding period using a large geolocator tracking dataset of 729 adult seabirds breeding at 13 colonies across the Northeast Atlantic and repeatedly tracked up to 7 years over a 9-year period. Additionally, we used a similarity index to calculate relative fidelity to either geographical sites or habitats and linear mixed-effects models to assess persistence of spatial site fidelity over multiple years. Results Both guillemot species exhibited IMSF across a large part of the genus’ range which persisted over multiple years. Individuals of both species and almost all colonies showed fidelity to geographical sites and not to specific habitats. Main conclusions Guillemots show IMSF that is best explained by site familiarity (fidelity to specific sites) rather than habitat specialization (fidelity to specific habitats). In the context of rapidly changing environments, favourable habitats may permanently shift locations and hence species displaying IMSF driven by site familiarity—such as the genus Uria—may not be able to adjust their migration strategies sufficiently fast to sustain individual fitness and ensure population persistence. |
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1365-2699 |
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1365-2699 |
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8025 |
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Céline Albert, Hálfdán Helgi Helgason, Maud Brault-Favrou, Gregory J. Robertson, Sébastien Descamps, Françoise Amélineau, Jóhannis Danielsen, Rune Dietz, Kyle Elliott, Kjell Einar Erikstad, Igor Eulaers, Alexey Ezhov, Michelle G. Fitzsimmons, Maria Gavrilo, Elena Golubova, David Grémillet, Scott Hatch, Nicholas P. Huffeldt, Dariusz Jakubas, Alexander Kitaysky, Yann Kolbeinsson, Yuri Krasnov, Svein-Håkon Lorentsen, Erlend Lorentzen, Mark L. Mallory, Benjamin Merkel, Flemming Ravn Merkel, William Montevecchi, Anders Mosbech, Bergur Olsen, Rachael A. Orben, Allison Patterson, Jennifer Provencher, Christine Plumejeaud, Isabeau Pratte, Tone Kristin Reiertsen, Heather Renner, Nora Rojek, Marc Romano, Hallvard Strøm, Geir Helge Systad, Akinori Takahashi, Jean-Baptiste Thiebot, Thorkell Lindberg Thórarinsson, Alexis P. Will, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort |
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Title |
Seasonal variation of mercury contamination in Arctic seabirds: A pan-Arctic assessment |
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2021 |
Publication |
Science of The Total Environment |
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750 |
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142201 |
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Feathers Metal Polar Seasonal variation Top predators |
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Mercury (Hg) is a natural trace element found in high concentrations in top predators, including Arctic seabirds. Most current knowledge about Hg concentrations in Arctic seabirds relates to exposure during the summer breeding period when researchers can easily access seabirds at colonies. However, the few studies focused on winter have shown higher Hg concentrations during the non-breeding period than breeding period in several tissues. Hence, improving knowledge about Hg exposure during the non-breeding period is crucial to understanding the threats and risks encountered by these species year-round. We used feathers of nine migratory alcid species occurring at high latitudes to study bird Hg exposure during both the breeding and non-breeding periods. Overall, Hg concentrations during the non-breeding period were ~3 times higher than during the breeding period. In addition, spatial differences were apparent within and between the Atlantic and Pacific regions. While Hg concentrations during the non-breeding period were ~9 times and ~3 times higher than during the breeding period for the West and East Atlantic respectively, Hg concentrations in the Pacific during the non-breeding period were only ~1.7 times higher than during the breeding period. In addition, individual Hg concentrations during the non-breeding period for most of the seabird colonies were above 5 μg g−1 dry weight (dw), which is considered to be the threshold at which deleterious effects are observed, suggesting that some breeding populations might be vulnerable to non-breeding Hg exposure. Since wintering area locations, and migration routes may influence seasonal Hg concentrations, it is crucial to improve our knowledge about spatial ecotoxicology to fully understand the risks associated with Hg contamination in Arctic seabirds. |
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0048-9697 |
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8026 |
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Benjamin Merkel, Sébastien Descamps, Nigel G. Yoccoz, David Grémillet, Per Fauchald, Jóhannis Danielsen, Francis Daunt, Kjell Einar Erikstad, Aleksey V. Ezhov, Mike P. Harris, Maria Gavrilo, Svein-Håkon Lorentsen, Tone K. Reiertsen, Geir H. Systad, Thorkell Lindberg Thórarinsson, Sarah Wanless, Hallvard Strøm |
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Title |
Strong migratory connectivity across meta-populations of sympatric North Atlantic seabirds |
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2021 |
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Marine Ecology Progress Series |
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SEA |
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Environmental niche Inter-population mixing Large-scale spatiotemporal dynamics Light-level geolocation Murres Population spread Seasonality |
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Abstract |
Identifying drivers of population trends in migratory species is difficult, as they can face many stressors while moving through different areas and environments during the annual cycle. To understand the potential of migrants to adjust to perturbations, it is critical to study the connection of different areas used by different populations during the annual cycle (i.e. migratory connectivity). Using a large-scale tracking data set of 662 individual seabirds from 2 sympatric auk meta-populations (common guillemots Uria aalge and Brünnich’s guillemots U. lomvia) breeding in 12 colonies throughout the Northeast Atlantic, we estimated migratory connectivity in seasonal space use as well as occupied environmental niches. We found strong migratory connectivity, within and between species. This was apparent through a combination of seasonal space use and occupied environmental niches. Brünnich’s guillemot populations grouped into 2 and common guillemot populations into 5 previously undescribed spatiotemporal clusters. Common guillemot populations clustered in accordance with the variable population trends exhibited by the species, while Brünnich’s guillemot populations are declining everywhere where known within the study area. Individuals from different breeding populations in both species were clustered in their space and environmental use, utilising only a fraction of the potential species-wide range. Further, space use varied among seasons, emphasising the variable constraints faced by both species during the different stages of their annual cycle. Our study highlights that considering spatiotemporal dynamics, not only in space but also in occupied environmental niches, improves our understanding of migratory connectivity and thus population vulnerability in the context of global change. |
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0171-8630, 1616-1599 |
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8027 |
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Mathilde Poirier, Dominique Fauteux, Gilles Gauthier, Florent Domine, Jean-François Lamarre |
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Title |
Snow hardness impacts intranivean locomotion of arctic small mammals |
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2021 |
Publication |
Ecosphere |
Abbreviated Journal |
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Volume |
12 |
Issue |
11 |
Pages |
e03835 |
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Arctic burrowing behavior digging fossorial hardness lemming locomotion rain-on-snow rodent snow subnivean tunnel |
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Fossorial locomotion is often considered as the most energetically costly of all terrestrial locomotion. Small arctic rodents, such as lemmings, dig tunnels not only in the soil but also through the snowpack, which is present for over 8 months of the year. Lemmings typically dig in the softest snow layer called the depth hoar but with climate change, melt-freeze and rain-on-snow (ROS) events are expected to increase in the Arctic, leading to a higher frequency of hardened snowpacks. We assessed the impacts of snow hardness on the locomotion of two lemming species showing different morphological adaptations for digging. We hypothesized that an increase in snow hardness would (1) decrease lemming performance and (2) increase their effort while digging, but those responses would differ between lemming species. We exposed four brown lemmings (Lemmus trimucronatus) and three collared lemmings (Dicrostonyx groenlandicus) to snow of different hardness (soft, hard, and ROS) during 30-min trials (n = 63 trials) in a cold room and filmed their behavior. We found that the digging speed and tunnel length of both species decreased with snow hardness and density, underlining the critical role of snow properties in affecting lemming digging performance. During the ROS trials, time spent digging by lemmings increased considerably and they also started using their incisors to help break the hard snow, validating our second hypothesis. Overall, digging performance was higher in collared lemmings, the species showing more morphological adaptations to digging, than in brown lemmings. We conclude that the digging performance of lemming is highly dependent on snowpack hardness and that the anticipated increase in ROS events may pose a critical energetic challenge for arctic rodent populations. |
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1042 |
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2150-8925 |
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8028 |
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Andreas Richter, Alexey A. Ekaykin, Matthias O. Willen, Vladimir Ya. Lipenkov, Andreas Groh, Sergey V. Popov, Mirko Scheinert, Martin Horwath, Reinhard Dietrich |
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Title |
Surface Mass Balance Models Vs. Stake Observations: A Comparison in the Lake Vostok Region, Central East Antarctica |
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2021 |
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Frontiers in Earth Science |
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9 |
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388 |
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The surface mass balance (SMB) is very low over the vast East Antarctic Plateau, for example in the Vostok region, where the mean SMB is on the order of 20–35 kg m-2 a-1. The observation and modeling of spatio-temporal SMB variations are equally challenging in this environment. Stake measurements carried out in the Vostok region provide SMB observations over half a century (1970–2019). This unique data set is compared with SMB estimations of the regional climate models RACMO2.3p2 (RACMO) and MAR3.11 (MAR). We focus on the SMB variations over time scales from months to decades. The comparison requires a rigorous assessment of the uncertainty in the stake observations and the spatial scale dependence of the temporal SMB variations. Our results show that RACMO estimates of annual and multi-year SMB agree well with the observations. The regression slope between modelled and observed temporal variations is close to 1.0 for this model. SMB simulations by MAR are affected by a positive bias which amounts to 6 kg m-2 a-1 at Vostok station and 2 kg m-2 a-1 along two stake profiles between Lake Vostok and Ridge B. None of the models is capable to reproduce the seasonal distributions of SMB and precipitation. Model SMB estimates are used in assessing the ice-mass balance and sea-level contribution of the Antarctic Ice Sheet by the input-output method. Our results provide insights into the uncertainty contribution of the SMB models to such assessments. |
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2296-6463 |
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8030 |
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Author |
Anzhou Cao, Zheng Guo, Xiaoyu Qi, Peiliang Li, Hailun He |
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Seasonal and nodal variations of predominant tidal constituents in the global ocean |
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2021 |
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Continental Shelf Research |
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217 |
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104372 |
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Fitting Modified two-step harmonic analysis Nodal modulation Seasonal variation Tide gauge Tides |
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Tides are one of the basic types of ocean water motions. Previous studies have reported that the M2 constituent exhibits seasonal variations (annual cycles) in some regions. However, based on the newly proposed method of modified two-step harmonic analysis (HA) and its application at 240 global tide gauges, we find that the M2 constituent as well as the S2 and K1 do not have significant seasonal variations at these tide gauges. The seasonal variations of the M2 constituent reported in previous studies are caused by its satellites, the H1 and H2 constituents, which are not resolved in these studies due to the short time window (one month or three months) used in HA. Because the frequency of the H1 (H2) constituent is equal to that of the M2 minus (plus) the frequency of annual cycles, the superposition of the M2, H1 and H2 constituents with constant amplitudes is equivalent to the M2 constituent with seasonally varying amplitudes. Compared with the new method, some adaptations to traditional HA aiming to capture variations in amplitudes and phase lags of constituents have some limitations, because they either neglect some satellites of the major constitutes or introduce spurious fluctuations resulting from an unreasonably large number of independent points. The nodal modulations of predominant constituents are also explored in this study. On the global scale, the nodal modulations of the M2, K1 and O1 constituents agree with the theoretical predictions, except a cold spot region with reduced nodal modulation in the Gulf of Maine and a hot spot region with enhanced nodal modulation in the South China Sea for the M2. Nodal modulation is also found for the S2 constituent (in theory, the S2 has no nodal modulation), which is 0.8% averaged at 164 tide gauges where the S2 is not too weak. |
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0278-4343 |
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8032 |
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