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Abstract: We present a 47-year-long record of sea surface temperature (SST) derived from Sr/Ca and U/Ca analysis of a massive Porites coral which grew at ~4150 calendar years before present (B.P.) in Vanuatu (southwest tropical Pacific Ocean). Mean SST is similar in both the modern instrumental record and paleorecord, and both exhibit El Niño-Southern Oscillation (ENSO) frequency SST oscillations. However, several strong decadal-frequency cooling events and a marked modulation of the seasonal SST cycle, with power at both ENSO and decadal frequencies, are observed in the paleorecord, which are unprecedented in the modern record. Category: geoscientificInformation Source: Supplement to: Corrège, Thierry; Delcroix, Thierry; Recy, Jacques; Beck, Warren; Cabioch, Guy; Le Cornec, Florence (2000): Evidence for stronger El Niño-Southern Oscillation (ENSO) Events in a Mid-Holocene massive coral. Paleoceanography, 15(4), 465-470, https://doi.org/10.1029/1999PA000409 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: -15.670000 * LONGITUDE: 167.000000 * ELEVATION: 4.7 m * METHOD|DEVICE: Core drilling
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Abstract: We investigate the long-term stability of El Niño-Southern Oscillation and Pacific Decadal Oscillation based on the examination of coccolithophore assemblages in a largely laminated 35 ka sedimentary record, retrieved in the Santa Barbara Basin (core MD02-2503). At a centennial scale coccolith assemblages indicate low primary production in the basin from 35 to 11.5 ka B.P., whereas the Holocene is characterized by high-productivity conditions. This pattern demonstrates the influence of the glacial-interglacial cycles on productivity and, by inference, on the nutrient supply by the upwelling cell off Point of Conception. On a shorter scale, laminations associated with Dansgaard-Oeschger events appear to be due to an injection of poorly oxygenated waters in the deepest part of the basin rather than anoxia due to high primary production. A seasonal sampling in seven laminated sections (spanning from 20 to 220 years) extracted from Holocene, Bølling-Allerød, and Dansgaard-Oeschger event 3 indicates El Niño probably existed continuously during the last 28 ka. The frequency of El Niño varied through time (between 1/2.5 and 1/5 event/a) and appearing to follow the precession cycle. El Niño exhibits higher (lower) frequencies when the precession values are lower (higher). Finally, the Holocene is characterized by a decrease in El Niño's frequencies due to the reinforcement of El Niño through this period. Category: geoscientificInformation Source: Supplement to: Grelaud, Michaël; Beaufort, Luc; Cuven, Stéphanie; Buchet, Noëlle (2009): Glacial to interglacial primary production and El Niño-Southern Oscillation dynamics inferred from coccolithophores of the Santa Barbara Basin. Paleoceanography, 24(1), PA1203, https://doi.org/10.1029/2007PA001578 Supplemental Information: Not Availble Coverage: Not Available
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Abstract: The Lamb weather type series is a subjective catalogue of daily atmospheric patterns and flow directions over the British Isles, covering the period 1861–1996. Based on synoptic maps, meteorologists have empirically classified surface pressure patterns over this area, which is a key area for the progression of Atlantic storm tracks towards Europe. We apply this classification to a set of daily pressure series from a few stations from western Europe, in order to reconstruct and to extend this daily weather type series back to 1781. We describe a statistical framework which provides, for each day, the weather types consistent enough with the observed pressure pattern, and their respective probability. Since the low frequency variability of synoptic conditions is directly related to the North Atlantic Oscillation (NAO), we derive from the weather type series an NAO index for winter. An interesting feature is a larger multidecadal variability during the nineteenth century than during the twentieth century. Category: geoscientificInformation Source: Supplement to: Delaygue, Gilles; Brönnimann, Stefan; Jones, Philip D; Blanchet, Juliette; Schwander, Mikhaël (2019): Reconstruction of Lamb weather type series back to the eighteenth century. Climate Dynamics, 52(9-10), 6131-6148, https://doi.org/10.1007/s00382-018-4506-7 Supplemental Information: Not Availble Coverage: Not Available
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Abstract: The upper 1200 m of pre-Pliocene sediment recovered by Cape Roberts Project (CRP) drilling off the Victoria Land coast of Antarctica between 1997-1999 has been subdivided into 54 unconformity-bound stratigraphic sequences, spanning the period c. 32 to 17 Ma. The sequences are recognised on the basis of the cyclical vertical stacking of their constituent lithofacies, which are enclosed by erosion surfaces produced during the grounding of the advancing ice margin onto the sea floor. Each sequence represents deposition in a range of offshore shelf to coastal glacimarine sedimentary environments during oscillations in the ice margin across the Western Ross Sea shelf, and coeval fluctuations in water depth. This paper applies spectral analysis techniques to depth- and time-series of sediment grain size (500 samples) for intervals of the core with adequate chronological data. Time series analysis of 0.5-l.0m-spaced grainsize data spanning sequences 9-11 (CRP-2/2A) and sequences 1-7 (CRP-3) suggests that the length of individual sequences correspond to Milankovitch frequencies, probably 41 k.y., but possibly as low as 100 k.y. Higher frequency periodic components at 23 k.y. (orbital precession) and 15-10 k.y. (sub-orbital) are recognised at the intrasequence-scale, and may represent climatic cycles akin to the ice rafting episodes described in the North Atlantic Ocean during the Quaternary. The cyclicity recorded by glacimarine sequences in CRP core provides direct evidence from the periphery of Antarctica for orbital oscillations in the size of the Oligocene-Early Miocene East Antarctic Ice Sheet. Category: geoscientificInformation Source: Supplement to: Naish, Tim R; Barrett, Peter J; Dunbar, Gavin B; Woolfe, Ken; Dunn, A G; Henrys, Stuart A; Claps, Michele; Powell, Ross; Fielding, Christopher R (2001): Sedimentary cyclicity in CRP drillcore, Victoria Land Basin, Antarctica. Terra Antartica, 8(3), 225-244, hdl:10013/epic.28205.d001 Supplemental Information: Not Availble Coverage: EVENT LABEL: (14.2 km at 096° true from Cape Roberts) * LATITUDE: -77.005983 * LONGITUDE: 163.719450 * DATE/TIME: 1998-10-01T00:00:00 * ELEVATION: -177.9 m * Recovery: 57.42 m * LOCATION: off Cape Roberts, Ross Sea, Antarctica * CAMPAIGN: CRP-2 * BASIS: Sampling/drilling from ice * METHOD|DEVICE: Core wireline system EVENT LABEL: * LATITUDE: -77.006000 * LONGITUDE: 163.719000 * DATE/TIME START: 1999-10-09T00:00:00 * DATE/TIME END: 1999-11-19T00:00:00 * ELEVATION: -295.0 m * Penetration: 939 m * Recovery: 936 m * LOCATION: Ross Sea * CAMPAIGN: CRP-3 * BASIS: Sampling/drilling from ice * METHOD|DEVICE: Core wireline system
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Abstract: The El Niño-Southern Oscillation (ENSO) is a globally important factor in today's climate dynamics. Annually laminated oil shales from the maar lake of Messel (Germany) provide high-resolution sedimentological and paleoenvironmental data of a time interval of ~600 k.y. during the Eocene greenhouse phase. Individual laminae consist of a light spring and summer algal layer (Tetraedron minimum layer) and a dark winter layer composed of terrigenous background sediment. Four sections were selected from the core of the Messel 2001 well in order to count varves and to measure total varve thickness and the thickess of light and dark laminae. Spectral analyses were done in order to detect possible cyclic fluctuations in varve thickness. Fluctuations are significant in the quasi-biennial (2.1-2.5 yr) and low-frequency band (2.8-3.5 yr, 4.9-5.6 yr), thus showing that algal growth as well as the background sedimentation were controlled by ENSO effects at least over a time interval of 600 k.y. This confirms the existence of a previously postulated robust Eocene ENSO. Significant peaks within a quasi-decadal (10-11 yr), interdecadal (17-26 yr), and multidecadal band (~52 yr, ~82 yr) show either the enduring influence of more or less cyclic instabilities or the influence of solar cycles. Category: geoscientificInformation Source: Supplement to: Lenz, Olaf K; Wilde, Volker; Riegel, Walter; Harms, Franz-Jürgen (2010): A 600 k.y. record of El Nino-Southern Oscillation (ENSO): Evidence for persisting teleconnections during the Middle Eocene greenhouse climate of Central Europe. Geology, 38(7), 627-630, https://doi.org/10.1130/G30889.1 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 49.917841 * LONGITUDE: 8.758867 * LOCATION: Messel, Germany * METHOD|DEVICE: Core drilling
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Abstract: Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the occurrence and future persistence of these endemic species. In order to evaluate the impact of past climate changes on the endemic Argan tree in southern Morocco, we reconstructed its modern range using an extensive pollen dataset. The modern pollen distribution off southwestern Morocco was then utilized to interpret the high-resolution pollen record with complementary micro-charcoal and XRF element records from a marine sediment core GeoB8601-3 off Cape Ghir in southwestern Morocco covering the last three millennia. This multi-proxy study has shown clear evidence of wetter conditions resulting in higher fluvial input which could be correlated with a negative mode of the North Atlantic Oscillation (NAO), in contrast to the published pollen and XRF element records from another nearby core that showed limited effect of climate changes. On the other hand, clear opposite trend between the pollen occurrences of Argania spinosa and the fire frequency was observed throughout our fossil record. The increase of Argania spinosa pollen occurrences, along with herbaceous taxa, and lower fire frequency might suggest an increase in human impact on the landscape leading to a sparse vegetation cover and subsequently increased erosion. The reconstructed pollen-based vegetation, micro-charcoal-based fire activities and geochemical changes in our marine record suggest interplay of climate and anthropogenic effects on the landscape. Category: geoscientificInformation Source: Supplement to: Zhao, Xueqin; Dupont, Lydie M; Cheddadi, Rachid; Kölling, Martin; Reddad, Hanane; Groeneveld, Jeroen; Ain-Lhout, Fatima Zohra; Bouimetarhan, Ilham (2019): Recent climatic and anthropogenic impacts on endemic species in southwestern Morocco. Quaternary Science Reviews, 221, 105889, https://doi.org/10.1016/j.quascirev.2019.105889 Supplemental Information: Not Availble Coverage: Not Available
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Abstract: Atoll islands are subject to a variety of processes that influence their geomorphological development. Analysis of historical shoreline changes using remotely sensed images has become an efficient approach to both quantify past changes and estimate future island response. However, the detection of long-term changes in beach width is challenging mainly for two reasons: first, data availability is limited for many remote Pacific islands. Second, beach environments are highly dynamic and strongly influenced by seasonal or episodic shoreline oscillations. Consequently, remote-sensing studies on beach morphodynamics of atoll islands deal with dynamic features covered by a low sampling frequency. Here we present a study of beach dynamics for nine islands on Takú Atoll, Papua New Guinea, over a seven-decade period. A considerable chronological gap between aerial photographs and satellite images was addressed by applying a new method that reweighted positions of the beach limit by identifying “outlier” shoreline positions. On top of natural beach variability observed along the reweighted beach sections, we found that one third of the analyzed islands show a statistically significant decrease in reweighted beach width since 1943. The total loss of beach area for all islands corresponds to 44% of the initial beach area. Variable shoreline trajectories suggest that changes in beach width on Takú Atoll are dependent on local control (that is, human activity and longshore sediment transport). Our results show that remote imagery with a low sampling frequency may be sufficient to characterize prominent morphological changes in planform beach configuration of reef islands. Category: geoscientificInformation Source: Supplement to: Mann, Thomas; Westphal, Hildegard (2014): Assessing long-term changes in the beach width of reef islands based on temporally fragmented remote sensing data. Remote Sensing, 6(8), 6961-6987, https://doi.org/10.3390/rs6086961 Supplemental Information: Not Availble Coverage: Not Available
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Abstract: Knowledge of past natural flood variability and controlling climate factors is of high value since it can be useful to refine projections of the future flood behavior under climate warming. In this context, we present a seasonally resolved 2000 year long flood frequency and intensity reconstruction from the southern Alpine slope (North Italy) using annually laminated (varved) lake sediments. Floods occurred predominantly during summer and autumn, whereas winter and spring events were rare. The all-season flood frequency and, particularly, the occurrence of summer events increased during solar minima, suggesting solar-induced circulation changes resembling negative conditions of the North Atlantic Oscillation as controlling atmospheric mechanism. Furthermore, the most extreme autumn events occurred during a period of warm Mediterranean sea surface temperature. Interpreting these results in regard to present climate change, our data set proposes for a warming scenario, a decrease in summer floods, but an increase in the intensity of autumn floods at the South-Alpine slope. Category: geoscientificInformation Source: Supplement to: Wirth, Stefanie B; Gilli, Adrian; Simonneau, Anaëlle; Ariztegui, Daniel; Vannière, Boris; Glur, Lukas; Chapron, Emmanuel; Magny, Michel; Anselmetti, Flavio S (2013): A 2000 year long seasonal record of floods in the southern European Alps. Geophysical Research Letters, 40(15), 4025-4029, https://doi.org/10.1002/grl.50741 Supplemental Information: Not Availble Coverage: EVENT LABEL: (S3) * LATITUDE: 45.876700 * LONGITUDE: 10.750600 * ELEVATION: 655.0 m * LOCATION: Central Alps * METHOD|DEVICE: Piston corer
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Abstract: The annually laminated oil shale from the Eocene maar lake at Messel (Germany) provides unique palaeoenvironmental and palaeoclimatological information for the Palaeogene greenhouse phase. Two palynological analyses of 6.3 and 70?kyr long records with a temporal resolution of 70 and 700?years respectively confirm vegetation and climate variability in the sub-Milankovitch range. This variability clearly corresponds to cyclic climate fluctuations indicating the influence of solar activity and a millennial-scale variability of the El Niño?Southern Oscillation also seen during the Quaternary icehouse system. This provides strong evidence of cyclic fluctuations in the sub-Milankovitch frequency band that represent a pervasive and persistent system not only of the Quaternary icehouse, but also throughout the entire Neogene and the Palaeogene greenhouse. This is proof for the long-term stability of the driving forces of natural climate change on Earth. Fluctuations in the frequency of palynomorphs indicate cyclic short-term quantitative changes in the composition of the vegetation. These changes were related to precipitation and corresponding fluctuations of the lake level as well as to changes in pollen production, transport and deposition. Category: geoscientificInformation Source: Supplement to: Lenz, Olaf K; Wilde, Volker; Riegel, Walter (2017): ENSO- and solar-driven sub-Milankovitch cyclicity in the Palaeogene greenhouse world; high-resolution pollen records from Eocene Lake Messel, Germany. Journal of the Geological Society, 174(1), 110-128, https://doi.org/10.1144/jgs2016-046 Supplemental Information: Not Availble Coverage: Not Available
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Abstract: In this study, we present a unique high-resolution Holocene record of oceanographic and climatic change based on analyses of diatom assemblages combined with biomarker data from a sediment core collected from the Vega Drift, eastern Antarctic Peninsula (EAP). These data add to the climate framework already established by high-resolution marine sedimentary records from the Palmer Deep, western Antarctic Peninsula (WAP). Heavy sea ice conditions and reduced primary productivity were observed prior to 7.4 ka B.P. in relation with the proximity of the glacial ice melt and calving. Subsequent Holocene oceanographic conditions were controlled by the interactions between the Westerlies-Antarctic Circumpolar Current (ACC)-Weddell Gyre dynamics. A warm period characterized by short seasonal sea ice duration associated with a southern shift of both ACC and Westerlies field persisted until 5 ka B.P. This warm episode was then followed by climate deterioration during the middle-to-late Holocene (5 to 1.9 ka B.P.) with a gradual increase in annual sea ice duration triggered by the expansion of the Weddell Gyre and a strong oceanic connection from the EAP to the WAP. Increase of benthic diatom species during this period was indicative of more summer/autumn storms, which was consistent with changes in synoptic atmospheric circulation and the establishment of low- to high-latitude teleconnections. Finally, the multicentennial scale variability of the Weddell Gyre intensity and storm frequency during the late Holocene appeared to be associated with the increased El Niño-Southern Oscillation frequency. Category: geoscientificInformation Source: Supplement to: Barbara, Loïc; Crosta, Xavier; Leventer, Amy; Schmidt, S; Etourneau, Johan; Domack, Eugene W; Massé, Guillaume (2016): Environmental responses of the Northeast Antarctic Peninsula to the Holocene climate variability. Paleoceanography, 31(1), 131-147, https://doi.org/10.1002/2015PA002785 Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: -63.717000 * LONGITUDE: -57.411000 * ELEVATION: -760.0 m * Recovery: 19.86 m * LOCATION: Vega Drift, Prince Gustav Channel, Antarctic Peninsula * CAMPAIGN: NBP00-03 * BASIS: Nathaniel B. Palmer * METHOD|DEVICE: Piston corer
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