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  • 1
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    Fe/K-ratios and pollen analysis of ODP Site 202-1239 (2017)
    PANGAEA
    In:  Supplement to: Grimmer, Friederike; Dupont, Lydie M; Lamy, Frank; Jung, Gerlinde; González, Catalina; Wefer, Gerold (2018): Early Pliocene vegetation and hydrology changes in western equatorial South America. Climate of the Past, 14(11), 1739-1754, https://doi.org/10.5194/cp-14-1739-2018
    Details
    Publication Date: 2023-03-03
    Description: Vegetation and climate change in nortwestern South America were studied using pollen analysis in combination with XRF scanning on marine sediments of ODP Site 1239 from the East Equatorial Pacific comprising the interval between 4.7 and 4.2 Ma. The study site is sensitive to latitudinal shifts of the Intertropical Convergence Zone (ITCZ) shifts insofar as a southward (northward) shift would result in increased (decreased) precipitation over Ecuador. The presented pollen record (46 samples) comprises representatives from five ecological groups: lowland rainforest, lower montane forest, upper montane forest, páramo, and broad range taxa. A broad tropical rainforest coverage persisted in the study area throughout the early Pliocene, without significant open vegetation below the forest line. Between 4.7 and 4.42 Ma, humidity increases, reaching its peak around 4.42 Ma, and slightly decreasing again afterwards. The stable, permanently humid conditions are rather in agreement with paleoceanographic data indicating a southward shift of the ITCZ, possibly in response to closure of the Central American Seaway. The presence of páramo vegetation indicates that the Western Cordillera of the northern Andes had already reached considerable elevation by the early Pliocene. The trend in iron/potassium-ratios (Fe/K) is similar to the pattern of humidity inferred from the pollen spectrum, showing the highest values around 4.46 Ma, thus supporting the hydrological interpretation of the pollen record.
    Keywords: Center for Marine Environmental Sciences; MARUM
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 2
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    Model simulation output data (CCSM3) related to uplift of Africa and Himalaya/Tibet Plateau and the influence on tropical African vegetation (2016)
    PANGAEA
    In:  Supplement to: Jung, Gerlinde; Prange, Matthias; Schulz, Michael (2016): Influence of topography on tropical African vegetation coverage. Climate Dynamics, 46(7), 2535-2549, https://doi.org/10.1007/s00382-015-2716-9
    Details
    Publication Date: 2023-03-03
    Description: Hominid evolution in the late Miocene has long been hypothesized to be linked to the retreat of the tropical rainforest in Africa. One cause for the climatic and vegetation change often considered was uplift of Africa, but also uplift of the Himalaya and the Tibetan Plateau was suggested to have impacted rainfall distribution over Africa. Recent proxy data suggest that in East Africa open grassland habitats were available to the common ancestors of hominins and apes long before their divergence and do not find evidence for a closed rainforest in the late Miocene. We used the coupled global general circulation model CCSM3 including an interactively coupled dynamic vegetation module to investigate the impact of topography on African hydro-climate and vegetation. We performed sensitivity experiments altering elevations of the Himalaya and the Tibetan Plateau as well as of East and Southern Africa. The simulations confirm the dominant impact of African topography for climate and vegetation development of the African tropics. Only a weak influence of prescribed Asian uplift on African climate could be detected. The model simulations show that rainforest coverage of Central Africa is strongly determined by the presence of elevated African topography. In East Africa, despite wetter conditions with lowered African topography, the conditions were not favorable enough to maintain a closed rainforest. A discussion of the results with respect to other model studies indicates a minor importance of vegetation–atmosphere or ocean–atmosphere feedbacks and a large dependence of the simulated vegetation response on the land surface/vegetation model.
    Keywords: Center for Marine Environmental Sciences; File content; File format; File name; File size; MARUM; Uniform resource locator/link to model result file
    Type: Dataset
    Format: text/tab-separated-values, 50 data points
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    DATA PANGAEA
  • 3
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    Model simulation output data (CCSM3) related to uplift of African topography and the intensification of upwelling in the Benguela region (2015)
    PANGAEA
    In:  Supplement to: Jung, Gerlinde; Prange, Matthias; Schulz, Michael (2014): Uplift of Africa as a potential cause for Neogene intensification of the Benguela upwelling system. Nature Geoscience, 7(10), 741-747, https://doi.org/10.1038/ngeo2249
    Details
    Publication Date: 2023-03-03
    Description: The Benguela Current, located off the west coast of southern Africa, is tied to a highly productive upwelling system**1. Over the past 12 million years, the current has cooled, and upwelling has intensified**2, 3, 4. These changes have been variously linked to atmospheric and oceanic changes associated with the glaciation of Antarctica and global cooling**5, the closure of the Central American Seaway**1, 6 or the further restriction of the Indonesian Seaway**3. The upwelling intensification also occurred during a period of substantial uplift of the African continent**7, 8. Here we use a coupled ocean-atmosphere general circulation model to test the effect of African uplift on Benguela upwelling. In our simulations, uplift in the East African Rift system and in southern and southwestern Africa induces an intensification of coastal low-level winds, which leads to increased oceanic upwelling of cool subsurface waters. We compare the effect of African uplift with the simulated impact of the Central American Seaway closure9, Indonesian Throughflow restriction10 and Antarctic glaciation**11, and find that African uplift has at least an equally strong influence as each of the three other factors. We therefore conclude that African uplift was an important factor in driving the cooling and strengthening of the Benguela Current and coastal upwelling during the late Miocene and Pliocene epochs.
    Keywords: Center for Marine Environmental Sciences; File content; File format; File name; File size; MARUM; Numerical experiments using the general circulation model CCSM3; Uniform resource locator/link to model result file
    Type: Dataset
    Format: text/tab-separated-values, 20 data points
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    DATA PANGAEA
  • 4
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    Dinoflagellate cyst counts of ODP Site 1081, Benguela Upwelling, Miocene-Pliocene (2016)
    PANGAEA
    In:  Supplement to: Hötzel, Sebastian; Dupont, Lydie M; Marret, Fabienne; Jung, Gerlinde; Wefer, Gerold (2016): Steps in the intensification of Benguela upwelling over the Walvis Ridge during Miocene and Pliocene. International Journal of Earth Sciences, 1-13, https://doi.org/10.1007/s00531-016-1309-0
    Details
    Publication Date: 2024-03-06
    Description: Using the Late Miocene to Pliocene organic-walled dinoflagellate cyst record of ODP Site 1081 we reconstruct and discuss the early upwelling history over the Walvis Ridge with a special focus on the movement of the Angola-Benguela Front (ABF). We suggest that during the Late Miocene the Angola Current flowed southwards over the Walvis Ridge more frequently than today because the ABF was probably located further south as a result of a weaker meridional temperature gradient. A possible strengthening of the meridional gradient during the latest Miocene to early Pliocene in combination with uplift of south-western Africa intensified the upwelling along the coast and increased the upwelling's filaments over the Walvis Ridge. An intermediate period from 6.2 to 5.5 Ma is shown by the dominance of Habibacysta tectata, cysts of a cool-tolerant dinoflagellate known from the northern Atlantic, indicating changing oceanic conditions contemporaneous with the Messinian Salinity Crisis. From 4.3 Ma on, the upwelling signal got stronger again and waters were well-mixed and nutrient-rich. Our results indicate a northward migration of the ABF as early as 7 Ma and the initial stepwise intensification of the BUS.
    Keywords: 175-1081A; Acomosphaera spp.; AGE; Ataxiodinium confusum; Ataxiodinium zevenboomii; Batiacasphaera hirsuta; Batiacasphaera micropapillata; Benguela Current, South Atlantic Ocean; Brigantedinium spp.; Counting, dinoflagellate cysts; DEPTH, sediment/rock; Dinoflagellate cyst indeterminata; Dinoflagellates, total; DRILL; Drilling/drill rig; Habibacysta tectata; Impagidinium aculeatum; Impagidinium paradoxum; Impagidinium patulum; Impagidinium species 2 after De Schepper & Head (2009); Impagidinium sphaericum; Impagidinium spp.; Impagidinium strialatum; Joides Resolution; Leg175; Lejeunecysta oliva; Lejeunecysta sabrina; Lejeunecysta spp.; Lingulodinium machaerophorum; Marker, added; Marker, found; Nematosphaeropsis labyrinthus; Ocean Drilling Program; ODP; Operculodinium centrocarpum; Operculodinium israelianum; Operculodinium janduchenei; Operculodinium spp.; Pentapharsodinium dalei; Pyxidinopsis reticulata; Quinquecuspis concreta; Sample code/label; Selenopemphix armageddonensis; Selenopemphix brevispinosa; Selenopemphix brevispinosa conspicua; Selenopemphix nephroides; Selenopemphix quanta; Spiniferites cf. mirabilis; Spiniferites membranaceus; Spiniferites mirabilis; Spiniferites ramosus; Spiniferites spp.; Sumatradinium soucouyantiae; Trinovantedinium applanatum; Trinovantedinium ferugnomatum; Trinovantedinium glorianum; Trinovantedinium papula; Tuberculodinium vancampoae; Volume
    Type: Dataset
    Format: text/tab-separated-values, 3408 data points
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  • 5
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    Iron/potassium-ratios of ODP Site 202-1239 (2017)
    PANGAEA
    Details
    Publication Date: 2024-01-09
    Keywords: 202-1239; AGE; COMPCORE; Composite Core; Equatorial East Pacific; Iron/Potassium ratio; Joides Resolution; Leg202; Ocean Drilling Program; ODP
    Type: Dataset
    Format: text/tab-separated-values, 652 data points
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    DATA PANGAEA
  • 6
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    Percentages of pollen, spores and clusteranalysis of ODP Site 202-1239 (2018)
    PANGAEA
    Details
    Publication Date: 2024-01-09
    Keywords: 202-1239A; 202-1239B; AGE; Alchornea; Alnus; Amaranthaceae; Ambrosia/Xanthium; Anemia-type; Artemisia; Asteraceae Tubuliflorae; Bocconia-type; Broad-range Taxa; Bromeliaceae; Clethra; Cyatheaceae; Cyperaceae; Daphnopsis; Depth, reference; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Elaphoglossum; Ericaceae; Event label; Hedyosmum; Humidity Indicators; Huperzia; Ilex; Indeterminata; Jamesonia/Eriosorus; Joides Resolution; Leg202; Lophosoria; Lower Montane Forest; Lowland rainforest; Lycopodium spp.; Malpighiaceae; Melastomataceae; Monolete psilate; Morella; Myrsine; Number of squares; Ocean Drilling Program; ODP; Paramo; Pityrogramma; Poaceae; Podocarpaceae; Pollen, varia; Pollen zone; Polylepis/Acaena; Polypodiaceae; Pteris grandifolia; Rhizophora; Rosaceae; Saccoloma elegans; Sample code/label; Selaginella; South Pacific Ocean; Spores, varia; Styloceras-type; Sum; Thelypteris; Trilete psilate; Upper Montane Forest; Vernonia; Wettinia
    Type: Dataset
    Format: text/tab-separated-values, 2632 data points
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  • 7
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    Pollen analysis of ODP Site 202-1239 (2017)
    PANGAEA
    Details
    Publication Date: 2024-05-18
    Keywords: 202-1239; AGE; Alchornea; Asteraceae Tubuliflorae; Broad-range Taxa; COMPCORE; Composite Core; Confidence interval; Cyathea; Cyperaceae; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Equatorial East Pacific; Hedyosmum; Herbs; Humidity Indicators; Huperzia; Jamesonia/Eriosorus; Joides Resolution; Leg202; Lower Montane Forest; Lowland rainforest; Ocean Drilling Program; ODP; Paramo; Poaceae; Pollen and Spores, total; Polylepis/Acaena-type; Principal investigator; Sample code/label; Trees and shrubs; Upper Montane Forest
    Type: Dataset
    Format: text/tab-separated-values, 3882 data points
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  • 8
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    Early Pliocene vegetation and hydrology changes in western equatorial South America (2018)
    In:  EPIC3Climate of the Past, 14(11), pp. 1739-1754, ISSN: 1814-9332
    Details
    Publication Date: 2020-03-13
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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    PAPER (OA)
  • 9
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    A Joint Soil-Vegetation-Atmospheric Water Tagging Procedure With WRF-Hydro: Implementation and Application to the Case of Precipitation Partitioning in the Upper Danube River Basin (2021)
    Details
    Publication Date: 2021-10-06
    Description: Atmospheric models such as the Weather Research and Forecasting (WRF) model provide a tool to evaluate the behavior of regional hydrological cycle components, including precipitation, evapotranspiration, soil water storage, and runoff. Recent model developments have focused on coupled atmospheric-hydrological modeling systems, such as WRF-Hydro, in order to account for subsurface, overland, and river flow and potentially improve the representation of land-atmosphere interactions. The aim of this study is to investigate the contribution of lateral terrestrial water flow to the regional hydrological cycle, with the help of a joint soil-vegetation-atmospheric water tagging procedure newly developed in the so-called WRF-tag and WRF-Hydro-tag models. An application of both models for the high precipitation event on 15 August 2008 in the German and Austrian parts of the upper Danube river basin (94,100 km2) is presented. The precipitation that fell in the basin during this event is considered as a water source, is tagged, and subsequently tracked for a 40-month period until December 2011. At the end of the study period, in both simulations, approximately 57% of the tagged water has run off, while 41% has evaporated back to the atmosphere, including 2% that has recycled in the upper Danube river basin as precipitation. In WRF-Hydro-tag, the surface evaporation of tagged water is slightly enhanced by surface flow infiltration and slightly reduced by subsurface lateral water flow in areas with low topography gradients. This affects the source precipitation recycling only in a negligible amount.
    Keywords: 551.5 ; soil-vegetation-atmospheric moisture tagging ; precipitation partitioning ; coupled modeling ; Danube river basin
    Language: English
    Type: map
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    CITATION GEO-LEO
  • 10
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    A Joint Soil‐Vegetation‐Atmospheric Modeling Procedure of Water Isotopologues: Implementation and Application to Different Climate Zones With WRF‐Hydro‐Iso (2021)
    Details
    Publication Date: 2022-03-29
    Description: Water isotopologues, as natural tracers of the hydrological cycle on Earth, provide a unique way to assess the skill of climate models in representing realistic atmospheric‐terrestrial water pathways. This study presents the newly developed WRF‐Hydro‐iso, which is a version of the coupled atmospheric‐hydrological WRF‐Hydro model enhanced with a joint soil‐vegetation‐atmospheric description of water isotopologue motions. It allows the consideration of isotopic fractionation processes during water phase changes in the atmosphere, the land surface, and the subsurface. For validation, WRF‐Hydro‐iso is applied to two different climate zones, namely Europe and Southern Africa under the present climate conditions. Each case is modeled with a domain employing a 5 km grid‐spacing coupled with a terrestrial subgrid employing a 500 m grid‐spacing in order to represent lateral terrestrial water flow. A 10‐year slice is simulated for 2003–2012, using ERA5 reanalyses as driving data. The boundary condition of isotopic variables is prescribed with mean values from a 10‐year simulation with the Community Earth System Model Version 1. WRF‐Hydro‐iso realistically reproduces the climatological variations of the isotopic concentrations δPO18 and δPH2 from the Global Network of Isotopes in Precipitation. In a sensitivity analysis, it is found that land surface evaporation fractionation increases the isotopic concentrations in the rootzone soil moisture and slightly decreases the isotopic concentrations in precipitation. Lateral terrestrial water flow minorly affects these isotopic concentrations through changes in evaporation‐transpiration partitioning.
    Description: Plain Language Summary: Global climate models are limited by their coarse resolution, which may reduce their meaningfulness. This problem can be circumvented for a specific region with regional climate models, which provide, for example, a detailed description of clouds and land‐atmosphere interactions. But it remains a question: How realistic is the model representation of water transport through the different compartments of the hydrological cycle, the atmosphere, the land, and the sea? A unique way to assess modeled water transport is the comparison to natural tracers, such as water isotopologues, which requires to include the fate of these water isotopologues in the model. This is what we pursue here with the newly developed WRF‐Hydro‐iso model. A model description and a proof of concept are provided for two climate zones, using the Global Network of Isotopes in Precipitation data set as reference.
    Description: Key Points: A new coupled atmospheric‐hydrological regional modeling system of water isotopologues is presented. Land surface evaporation fractionation increases the isotopic concentrations in the rootzone. Lateral terrestrial water flow has a minor effect on isotopic concentrations in the rootzone.
    Description: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659
    Description: German Federal Ministry of Science and Education
    Description: Bavarian State Ministry of Science and the Arts
    Keywords: ddc:551.6
    Language: English
    Type: doc-type:article
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