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  • Abstract: Grasslands cover 41.7% of China's land surface and distribute mainly in NW China. To project future change of grassland fires, it is essential to explore paleofire dynamics. However, comparatively little is known about the patterns and driving forces of grassland fires in NW China due to the scarcity of paleorecords. Here, we present Holocene sedimentary records of grassland fire and vegetation in westerly-dominated Xinjiang (NW China) to examine fire-fuel-climate interactions. We find that grassland fire-regime is fuel-limited, consistent with other grasslands worldwide. We reveal that burning increased throughout the Holocene, due to increasing moisture, grass cover, fuel load and temperature of spring fire season. The Holocene pattern of burning coincides with several other records nearby and a global-scale grassland fire record. Our results are different from monsoonal China where fuel load is not a constraining factor and more (less) fires occurred during colder/drier (warmer/moister) periods in the Holocene. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 44.970000 * LONGITUDE: 128.801100 * ELEVATION: 1300.0 m * Recovery: 126.75 cm * LOCATION: Wenquan County, Xinjiang Province, Northwest China * METHOD/DEVICE: Drilling/drill rig
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  • Abstract: Data presented here were collected during the cruise HE533 with RV HEINCKE from Bremerhaven, Germany to Bremerhaven, Germany (May 16, 2019 - June 12, 2019). In total, 75 underwater light profiles were collected at 29 stations, using a free-falling hyperspectral light profiler. The system used was a SEABIRD HyperPro II (SN 099, former Satlantic), equipped with a irradiance sensor to measure downwelling irradiance (Ed, SN 262) and a radiance sensor for upwelling radiance (Lu, SN 227). A reference unit was attached to the ship to measure the above water irradiance (Es, SN 223). The sensors were calibrated by the manufacturer and validated prior to the cruise with a reference lamp. Data were recorded with the SatView software (V 2.9.5_7) and processed from raw to Level1, 1b, 2, 2s to Level 3a using the ProSoft Processing software (V 7.7.19_2). Measured data were binned in 0.5 m depth intervals. A dark correction was made automatically based on shutter measurements by the instrument. Measurements with a tilt higher than 5° were not taken into account during processing. Spectra were interpolated to 1 nm intervals. For each station the hyperspectral profiles for each parameter cover the wavelength range from 400-700 nm, for Ed and Es in [W/m² nm], for Lu in [W/m² nm sr]. For Ed, Lu and Es descriptive statistics are given including min, max, mean, median and standard deviation of the tilt and the photosynthetically active radiation PAR [µmol photons/m² s (sr)], integrated from 400 - 700 nm. Statistics are not given for profiles which do not reach the 1% PAR depth. To allow an assignment of above water conditions to the respective depth measurements, Es spectra were given as a function of depth, recalculated from data Level2s. The Profiler measurements were only conducted during daylight. Raw data are available on request from the principal investigator. Chief Scientist of HE533: Dr. Uwe John, Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: The Intertropical Convergence Zone (ITCZ), which is the heaviest rain belt on Earth, significantly influences global hydroclimate change and livelihood of nearly 40% of the global population. However, long-term precipitation records are sparse from the Indo-Pacific region, especially from the southern margin of the Indo-Pacific ITCZ, restricting our understanding of the overall natural variability of the ITCZ in the past. In this study, we present a new summer monsoonal precipitation record that spans the last 410 kyr from the southern margin of the Indo-Pacific ITCZ, based on the logarithmic ratio between terrigenous fraction K and pelagic fraction Ca (ln(K/Ca)). Contents of the both elements were derived from X-ray fluorescence scanning on sediment cores from Site U1483 (13°05.24′ S, 121°48.25′ E, water depth 1733 m) that was drilled offshore northwestern Australia during International Ocean Discovery Program Expedition 363. Comparison of the new precipitation record with published precipitation records from the northern margin and meteorological centre of the Indo-Pacific ITCZ shows that precipitation changed nearly in phase between the hemispheres on the precession band, possibly linked to expansion and contraction in the latitudinal extent of the Indo-Pacific ITCZ. In contrast, interhemispheric precipitation was nearly in anti-phase on the obliquity band, likely due to latitudinal migration of the Indo-Pacific ITCZ. Our findings imply that tropical hydroclimate cycles were regulated by the orbital forcing but with significantly different response to changes of the ITCZ on precession and obliquity bands. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Data presented here were collected during the cruise HE492 with RV HEINCKE from Trondheim, Norway to Longyearbyen, Norway (July 29, 2017 - August 17, 2017). In total, 71 underwater light profiles were collected at 37 stations, using a free-falling hyperspectral light profiler. The system used was a SEABIRD HyperPro II (SN 099, former Satlantic), equipped with a irradiance sensor to measure downwelling irradiance (Ed, SN 262) and a radiance sensor for upwelling radiance (Lu, SN 227). A reference unit was attached to the ship to measure the above water irradiance (Es, SN 223). The sensors were calibrated by the manufacturer and validated prior to the cruise with a reference lamp. Data were recorded with the SatView software (V 2.9.5_7) and processed from raw to Level1, 1b, 2, 2s to Level 3a using the ProSoft Processing software (V 7.7.19_2). Measured data were binned in 0.5 m depth intervals. A dark correction was made automatically based on shutter measurements by the instrument. Measurements with a tilt higher than 5° were not taken into account during processing. Spectra were interpolated to 1 nm intervals. For each station the hyperspectral profiles for each parameter cover the wavelength range from 400-700 nm, for Ed and Es in [W/m² nm], for Lu in [W/m² nm sr]. For Ed, Lu and Es descriptive statistics are given including min, max, mean, median and standard deviation of the tilt and the photosynthetically active radiation PAR [µmol photons/m² s (sr)], integrated from 400 - 700 nm. Statistics are not given for profiles which do not reach the 1% PAR depth. To allow an assignment of above water conditions to the respective depth measurements, Es spectra were given as a function of depth, recalculated from data Level2s. The Profiler measurements were only conducted during daylight. Raw data are available on request from the principal investigator. Chief Scientist of HE492: Dr. Uwe John, Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Biển Hồ lake (14°03'03.5″ N, 108°00'00.2″ E) is a volcanic crater (i.e. maar) in Vietnam's Central Highlands that has been accumulating sediment since the Pleistocene. Here we show data from our bathymetric surveys and physical, chemical and diatom analyses of the uppermost sediment (0-2 m) (NAFOSTED project 105.99-2018.316). The data document environmental history recorded over the last 70 years in Biển Hồ Maar sediment and provide an empirical basis for the interpretation of Biển Hồ's deeper Holocene and pre-Holocene sedimentary record. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Lateglacial/early Holocene interval from the sediment core JM09-020GC recovered in Storfjordrenna (western Barents Sea) has been studied for benthic foraminifera assemblages, stable isotopes, IRD, vivianite microconcretions, magnetic susceptibility, and elemental composition in order to identify the causes and mechanisms of abrupt climate change during the Younger Dryas. The core was retrieved with R/V Jan Mayen (University of Tromsø – The Arctic University of Norway, UiT) in November 2009 from the Storfjordrenna (76°31489' N, 19°69957' E) at a bottom depth of 253 m. Prior to sediment core opening, the magnetic susceptibility was measured using a loop sensor installed on a GEOTEK Multi Sensor Core Logger at the Department of Geology, UiT. Core sections were stored in the laboratory for one day prior to measurements, thus allowing the sediments to adjust to room temperature and avoiding measurement errors related to temperature changes (Weber et al., 1997). Qualitative element-geochemical measurements were performed with Avaatech X-ray fluorescence (XRF) core scanner using the following settings: 10 kV, 1000 µA, 10-s measuring time, and no filter. Sediment samples for foraminiferal and vivianite analyses were freeze-dried, weighed, and wet sieved using sieves with mesh sizes of 500 µm and 100 µm. The residues were dried, weighed again, and subsequently split on a dry micro-splitter. Where possible, at least 300 specimens of foraminifera were counted in every 1 cm of sediment. Species identification under a binocular microscope (Nikon SMZ1500) was supported using the classification of Loeblich and Tappan (1987), with few exceptions, and percentages of the eight indicator species were applied. The benthic foraminiferal abundance and ice-rafted debris (IRD; grains >500 µm) were counted under a stereo-microscope and expressed as flux values (number of specimens/grains cm-2 ka-1) using the bulk sediment density and sediment accumulation rate. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: EVENT LABEL: * LATITUDE: 76.314890 * LONGITUDE: 19.699570 * ELEVATION: -253.0 m * CAMPAIGN: JM09702 * BASIS: Jan Mayen * METHOD/DEVICE: Gravity corer
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  • Abstract: Data presented here were collected during the cruise MSM56 with MARIA S MERIAN from Longyearbyen, Svalbard to Reykjavik, Iceland (July 2nd, 2016 - July 25th, 2016). In total, 133 underwater light profiles were collected at 68 stations (with at least three repititions), using a free-falling hyperspectral light profiler. The system used was a SEABIRD HyperPro II (SN 143, former Satlantic), equipped with a irradiance sensor to measure downwelling irradiance (Ed, SN 392) and a radiance sensor for upwelling radiance (Lu, SN 323). A reference unit was attached to the ship to measure the above water irradiance (Es, SN 393). The sensors were pre-calibrated by the manufacturer. Data were recorded with the SatView software (V 2.9.5_7) and processed from raw to Level1, 1b, 2, 2s to Level 3a using the ProSoft Processing software (V 7.7.19_2). Measured data were binned in 0.5 m depth intervals. A dark correction was made automatically based on shutter measurements by the instrument. Measurements with a tilt higher than 5° were not taken into account during processing. Spectra were interpolated to 1 nm intervals. For each station the hyperspectral profiles for each parameter cover the wavelength range from 400-700 nm, for Ed and Es in [W/m² nm], for Lu in [W/m² nm sr]. For Ed, Lu and Es descriptive statistics are given including min, max, mean, median and standard deviation of the tilt and the photosynthetically active radiation PAR [µmol photons/m² s (sr)], integrated from 400 - 700 nm. Statistics are not given for profiles which do not reach the 1% PAR depth. To allow an assignment of above water conditions to the respective depth measurements, Es spectra were given as a function of depth, recalculated from data Level2s. The profiler measurements were only conducted during daylight. Raw data are available on request from the principal investigator. Chief Scientist of MSM56: Dr. Koch, B. P., Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: Data presented here were collected during the cruise MSM65 with MARIA S MERIAN from St.John's, Newfoundland, Canada to Nuuk, Greenland (June 26th, 2017 - July 19th, 2017). In total, 116 underwater light profiles were collected at 68 stations (with at least three repititions), using a free-falling hyperspectral light profiler. The system used was a SEABIRD HyperPro II (SN 189, former Satlantic), equipped with a irradiance sensor to measure downwelling irradiance (Ed, SN 532) and a radiance sensor for upwelling radiance (Lu, SN 421). A reference unit was attached to the ship to measure the above water irradiance (Es, SN 533). The sensors were pre-calibrated by the manufacturer and validated prior to the cruise with a reference lamp. Data were recorded with the SatView software (V 2.9.5_7) and processed from raw to Level1, 1b, 2, 2s to Level 3a using the ProSoft Processing software (V 7.7.19_2). Measured data were binned in 0.5 m depth intervals. A dark correction was made automatically based on shutter measurements by the instrument. Measurements with a tilt higher than 5° were not taken into account during processing. Spectra were interpolated to 1 nm intervals. For each station the hyperspectral profiles for each parameter cover the wavelength range from 400-700 nm, for Ed and Es in [W/m² nm], for Lu in [W/m² nm sr]. For Ed, Lu and Es descriptive statistics are given including min, max, mean, median and standard deviation of the tilt and the photosynthetically active radiation PAR [µmol photons/m² s (sr)], integrated from 400 - 700 nm. Statistics are not given for profiles which do not reach the 1% PAR depth. To allow an assignment of above water conditions to the respective depth measurements, Es spectra were given as a function of depth, recalculated from data Level2s. The profiler measurements were only conducted during daylight. Raw data are available on request from the principal investigator. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: The evolution of intermediate circulation in the northern Indian Ocean since the last deglaciation has been reconstructed from two marine cores located at intermediate depths off the southern tip of India (MD77-191) and in the northern Bay of Bengal (MD77-176). This data provide high resolution records of benthic and planktonic foraminiferal δ13C, δ18O, and elemental ratios (Mg/Ca, Sr/Ca, Li/Ca, Mg/Li and U/Ca) from these two cores in the northern Indian Ocean. Stable isotope analyses were performed on well-preserved (clean and intact) samples of planktonic foraminifera Globigerinoides ruber and on benthic foraminifera Cibicidoides wuellerstorfi, Cibicidoides pachyderma and Uvigerina peregrina from MD77-191 to produce the most complete records. Mg/Ca, Sr/Ca, U/Ca and Li/Ca ratios were measured in shells of the aragonite epi-faunal benthic foraminifera H. elegans from MD77-191. Only the Mg/Ca and Sr/Ca results are available for MD77-176 due to the paucity of material, and the difficulty in measuring the Li/Ca and U/Ca ratios on very small samples. Benthic foraminiferal oxygen and carbon isotopes with H. elegans trace element ratios were combined to trace the evolution of past intermediate-deep water masses in the northern Indian Ocean since the last deglaciation and constrain ocean-atmosphere exchanges during the two-stage increase in atmospheric CO2 across the last deglaciation. Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
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  • Abstract: The presence-absence data for macrobenthic fauna that has been collected in Mingulay Reef Complex (Scotland, UK) across 79 stations over the years 2003, 2005, 2009, 2010 and 2011. The collection of the benthic samples has been carried out using a Van-Veen grab, mainly from hard habitats (e.g. live and dead coral framework). About 60% of the macrofaunal specimens have been identified at species level using high quality taxonomic keys and advice from taxonomy experts. Most common taxonomic groups analysed here are molluscs, polychaetes, arthropods, bryozoans, anthozoans, tunicates and brachiopods. The collection of the specimens is now deposited at the National Museums of Scotland (see the attached excel file for details). The enviromental data contains information about coordinates and environmental settings at stations where macrobenthic samples mentioned above, were collected. The environmental settings that are included in the file refer to the years 2003, 2005, 2009, 2010, 2011. For more information on the environmental variables have a look in Henry et al. 2010 (doi:10.1007/s00338-009-0577-6) and Henry et al. 2013 (doi:10.5194/bg-10-2737-2013). The environmental variables included in the excel file are: type of macrohabitat (i.e. muddy sand, rubble, rock, live coral, dead framework, live & dead framework), depth (m), slope, ruggedness, broad-scale bathymetric position index, fine-scale bathymetric position index, average current speed (m/s), maximum current speed (m/s), northness, eastness, winter North Atlantic Oscillation Index (same year), winter North Atlantic Oscillation Index (previous year), annual average bottom temperature (same year), annual average bottom salinity (same year). Extraction of bathymetric (depth) and topographic data [slope, aspect, northness, eastness, ruggedness, standardised broad-scale bathymetric position index (BPI; with an inner radius of 1 cell and an outer radius of 5 cells), fine-scale BPI (with an inner radius of 1 cell and an outer radius of 3 cells)] was based on multibeam echosounder data, using the Spatial Analyst and Benthic Terrain Modeler toolboxes in ArcGIS v.10.6.1 Average and maximum current speed values (m/s) were extracted by the ArcGIS v. 10.6.1 Spatial Analyst toolbox using data generated by a high-resolution 3D ocean model created for the MRC by Moreno-Navas et al. (2014). Data for the winter NAOI (DJFM) (Hurrell et al., 2003) were downloaded from the National Center for Atmospheric Research/University Corporation for Atmospheric Research website (climatedataguide.ucar.edu; data accessed on 28/02/2019). Category: geoscientificInformation Source: Not Available Supplemental Information: Not Availble Coverage: Not Available
    Data Types:
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    • Tabular Data
    • Text