cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.1594/pangaea.955561
title: ArcLeads: Daily sea-ice lead maps for the Arctic, 2002-2021, NOV-APR

description: The presence of sea-ice leads represents a key feature of the Arctic sea ice cover. Leads promote the flux of sensible and latent heat from the ocean to the cold winter atmosphere and are thereby crucial for air-sea-ice-ocean interactions. Especially in light of the observed trends in Arctic sea-ice extent, and with respect to the projected future changes in the Arctic climate system , the structure and dynamics of leads represent essential information for global change monitoring. We here present daily lead maps for the Arctic, for winter months NOV-APR in the period 2002-2021. The data were derived from MODIS thermal infrared imagery with 1 km² spatial resolution (Reiser et al., 2020). The ArcLeads data set contains daily categorical lead maps including classes for sea ice, leads, clouds and artefacts. The data come in EPSG:3413 (subset) projection and are provided as annual NetCDF files each including lat/lon grids. This is an update to the dataset provided in https://doi.org/10.1594/PANGAEA.917588.
DOI: 10.1594/pangaea.971475
title: Alkenone sea surface temperature from the Chiba Composition Section

description: This study displays the high-time resolution of paleo-sea surface temperature (SST) covering the marine isotope stage (MIS) 19 based on the unsaturation ratio of long-chain alkenones (UK'37) retrieved from the Chiba Composition Section (CbCS), central Japan. The CbCS consists of five sections: the Yoro River (35°17.41N; 140°08.48E), Yoro-Tabuchi (35°17.41N; 140°08.49E) and Urajiro (35°16.85N; 140°07.47E) sections. A total of 149 samples were processed for biomarker analyses from the Yoro-Tabuchi (ID: TB2-xx), Yoro River (ID: YT-xxx and TB-xxx), and Urajiro (ID: YW-xxx) sections of the CbCS. Please see Haneda et al. (2020, doi:10.1016/j.epsl.2019.115936) for the sample stratigraphy. After the surface was cleaned ultrasonically with ethanol, it was freeze-dried and ground into a fine powder. The powdered sediment (6-7 g) was extracted via ultrasonication with dichloromethane, dichloromethane/methanol (1:1, v/v), and methanol. The combined supernatant was dried under N2 gas and extracted with n-hexane from distilled water to obtain the neutral components. The extracted lipids were separated into four subfractions via silica gel column chromatography. The hydrocarbon fraction was eluted with n-hexane/dichloromethane (95:5, v/v). Then, the ketone fraction was eluted with n-hexane/dichloromethane (1:4, v/v) for alkenone analysis. Then, the ketones' fraction was introduced into a gas chromatograph with a mass-selective detector and a flame ionization detector (model 7890A, Agilent Technology) equipped with a VF-5ms fused silica capillary column (30 m × 0.25 mm internal diameter with 0.25 μm film, Agilent Technology). The oven temperature was programmed as follows: maintained at 40 °C for 2 min, raised to 120 °C at 30 °C/min, raised to 300 °C at 6 °C/min, and maintained at 300 °C for 20 min. Alkenone unsaturation ratios (UK'37) were converted into SSTs (℃) using the following calibration.SST = (UK'37 - 0.039)/0.034
DOI: 10.1594/pangaea.971305
title: Errina fissurata stable carbon and oxygen isotopes from Adare Basin, Ross Sea

description: The Errina fissurata coral specimens for this study were collected aboard the U.S. Antarctic Program expedition NBP07-01 near Cape Adare in the western Ross Sea. Seamounts on the outer continental shelf were dredged at a water depth ranging 400 m to 600 m and the corals used here were from the fifth through seventh dredges (D05–D07). The recovered corals were predominantly stylasterids (Errina spp.). Specimens were recovered both alive and dead (as evidenced by their pigmentation), some with growth tips intact. For this study, one live-collected and one dead-collected E. fissurata were selected for isotopic analyses (EA-11 and EA-12, respectively), targeting the longest whole specimens ranging from ~9 to 10 cm long. Coral specimens were sliced perpendicular to their vertical growth axes and the flat horizontal surfaces were sampled for stable oxygen and carbon isotope analyses. These analyses were designed to map the isotopic values across the coral and determine regions where the vital effects would obscure an environmental signal and inform future paleotemperature reconstructions.
DOI: 10.1594/pangaea.962904
title: Binary sea ice lead maps derived from Sentinel-1 SAR images during MOSAiC expedition

description: During winter, a significant part of the Arctic Ocean is covered with sea ice. Sea ice works as an insulation layer between the ocean and the atmosphere. The presence of leads is an important feature of the Arctic sea ice cover. Leads are areas with open water or thin ice, which are usually of elongated shape. Leads regulate the heat, gas, and moisture fluxes between the ocean and the atmosphere and are places of increased sea ice production, during periods of freezing conditions. Here binary lead maps derived from Sentinel-1 SAR images covering the MOSAiC expedition, which took place in the Central Arctic in 2019-2020, are presented. The data set contains 1596 classified Sentinel-1 scenes acquired in the extra wide swath (EW) mode with 400 km swath width and 40 meters pixel spacing. The maps are produced with a binary classification algorithm based on a convolutional neural network. Results are provided as geotiff images in the SAR geometry with the native SAR 40 meters pixel size. Georeferencing is done with ground control points corresponding to the ground control points provided with Sentinel-1 images.
description: Scene metadata include scene name, central coordinate (lat and lon), acquisition time. See https://sentinel.esa.int/web/sentinel/user-guides/sentinel-1-sar/naming-conventions for the file naming convention.
DOI: 10.1594/pangaea.966184
title: Stable water isotopes of seawater samples from the MOSAiC expedition 2019/2020

description: Seawater samples for stable oxygen water isotopes (δ18O) were taken during leg 1-5 of the MOSAIC expedition either from the Ocean City (OC CTD) on the main MOSAiC ice floe or from the shipboard CTD (PS CTD). Analysis for δ18O where conducted at the Leibniz Laboratory (LLK, Kiel, Germany) with mass-spectroscopy, applying the CO2- water isotope equilibration technique on at least 2 sub-samples on a Finnigan gas bench II unit coupled to a Finnigan DeltaPlusXL. A subset of stations were analyzed at AWI and published separately as Mellat et al. 2023 (https://doi.org/10.1594/PANGAEA.958464).
DOI: 10.1594/pangaea.941470
title: Integrated water vapour derived from the MiRAC-P microwave radiometer onboard the Polarstern during the MOSAiC expedition

description: The data set contains daily files of path integrated amount of water vapour (precipitable water, prw) derived from the MiRAC-P (or LHUMPRO-243-340) microwave radiometer (see Mech et al., 2019) onboard the Polarstern during cruise PS122 (MOSAiC expedition). The data covers the range October 2019 to October 2020. MiRAC-P measures atmospheric radiation in six double side band averaged G band (183.31 +/- 0.6 to 183.31 +/- 7.5 GHz) and two higher frequency (243 and 340 GHz) channels. The different sensitivity to humidity of the channels allow a derivation of the path integrated amount of water vapour (prw). A Neural Network retrieval has been used to derive prw. The uncertainty of prw is given as the variable's comment attribute and describes the expected standard error. Prw is provided for all available times so that it is up to the user to decide whether or not to use the values if quality flags are set.
DOI: 10.1594/pangaea.961767
title: Snow depth and sea ice thickness derived from a SIMBA buoy (FMI02) during 2012/2013

description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. Snow depth and ice thickness were derived manually by investigating the SIMBA_ET vertical temperature profiles. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m.This dataset provides snow depth and ice thickness derived from temperature data. The snow depth values mean snow accumulation above the reference surface (zero). The ice thickness values mean ice thickness growth below the initial reference surface (zero).
DOI: 10.1594/pangaea.961768
title: SIMBA buoy (FMI02) temperature measurement during 2012/2013

description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. This dataset provides SIMBA environmental temperature (SIMBA_ET).
description: Sensor 1 was placed in the air; Sensor 240 was placed in the ocean.
DOI: 10.1594/pangaea.964520
title: Melt pond bathymetry of the MOSAiC floe derived by photogrammetry - spatially fully resolved pond depth maps of an Arctic sea ice floe

description: A newly developed method to derive melt pond bathymetry from aerial images allowed us to compile spatially fully resolved maps of pond depth on the MOSAiC floe from three measurement flights on 30 June, 17 July, and 22 July 2020. The pond bathymetry maps provide an unprecedented comprehensive insight into the spatial and temporal development of ponds and their geometry. They were derived to better understand pond evolution, determine the volume of water contained in the ponds, and eventually obtain improved parameterizations for ponds. The data is provided in GeoTIFF raster format, with every pixel in ponds containing the depth at that location in meters, downward negative. Pond bathymetry was calculated from orthomosaics and digital elevation models processed from helicopter aerial images collected on MOSAiC floe grid surveys.Pond bathymetry is stored in GeoTIFFs, containing pond depth in meters, in the negative downward direction. Only regions classified as ponds with the classification algorithm PASTA-ice are included. Some pond-like objects on the floe were classified as submerged ice/open water due to their visual appearance or connection to the floe edge and are therefore not included. The raster data is projected in WGS 84 / NSIDC Sea Ice Polar Stereographic North (EPSG:3413). It was derived from the orthomosaics and DEMs presented in doi:10.1594/PANGAEA.949433 and can therefore be overlaid directly with this data.
DOI: 10.1594/pangaea.941407
title: Brightness temperatures of the MiRAC-P microwave radiometer onboard the Polarstern during the MOSAiC expedition

description: The data set contains daily files of atmospheric radiation measured by the MiRAC-P (or LHUMPRO-243-340) microwave radiometer (see Mech et al., 2019) onboard the Polarstern during cruise PS122 (MOSAiC expedition). The data covers the range October 2019 to October 2020. The atmospheric radiation measurements are given as brightness temperatures in six double side band averaged G band (183.31 +/- 0.6 to 183.31 +/- 7.5 GHz) and two higher frequency (243 and 340 GHz) channels. The brightness temperatures are provided for all available times so that it is up to the user to decide whether or not to use the values if quality flags are set. Additionally included are temperature, pressure and humidity measurements at the instrument location as well as quality flags characterizing the instrument and retrieval performance.
DOI: 10.1594/pangaea.962783
title: GISP2 ice-core volcanic sulfate concentration and deposition between 2635 and 2638 m depth (c. 80 ka BP)

description: We present continuous records of 1 cm resolved sodium, sulfur, non-sea-salt sulfur, size-resolved insoluble particle concentrations and liquid conductivity using a Continuous Flow Analysis (CFA) system (McConnell et al., 2017) from the Greenland Ice Sheet Project Two (GISP2; 72.97°N, 38.80°W) ice core and estimated volcanic sulfate mass depositions for the depth interval 2635-2638 m (equivalent to an age of c. 80 ka BP on GICC05modelext (Seierstad et al., 2014) and 79.5 ka BP on AICC2012 (Veres et al., 2013). The reconstruction is based on sulfur measurements employing high-resolution continuous flow analysis coupled to inductively coupled plasma mass spectrometry performed at the Desert Research Institute (Reno, NV, USA) under (class 100) cleanroom conditions. Volcanic eruptions are detected when annual sulfur concentrations exceeded the background concentrations + 4 times the median of the absolute deviation. Background concentrations are estimated using a 101-point running median. Volcanic sulfate deposition rates are calculated by subtracting the background concentrations from total sulfate equivalent (i.e. sulfur x 3) concentrations using thinning corrected estimates of mean ice accumulation rates at the ice-core site.
DOI: 10.1594/pangaea.957171
title: Algal pigment concentrations in meltponds and leads during the Arctic MOSAiC-expedition (Leg 4 and 5)

description: Algal pigment concentrations were retrieved from meltponds and leads, during Leg 4 and 5 of the MOSAiC expedition (Multidisciplinary drifting Observatory for the Study of Arctic Climate) in 2020. The summer increase in meltpond area and open lead water in the Arctic associated with increased light availability is of specific significance for biological production within the Arctic system (Smith et al. 2023). Over a period of 3.5 months, 46 samples have been collected and analysed. After extraction in 90 % acetone, samples were analysed using high-performance liquid chromatography (HPLC) on a Waters system. Algal pigments contain a multiple set of information. Firstly, pigment concentrations can show the presence of algal biomass in the various water masses sampled. Secondly, marker pigments can reveal seasonal and temporal dynamics in algal community structure, by discerning specific algal classes like diatoms, cryptophytes, haptophytes and chlorophytes that have specific roles in biogeochemical cycles. Thirdly, certain pigments are indicative of the (photo)-physiological state of micro-algae and fourth, degradation products of the main chlorophyll a pigment further give an indication about senescence and grazing in the various habitats.
DOI: 10.15468/dl.7hhvcn
title: Occurrence Download

description: A dataset containing 36964 species occurrences available in GBIF matching the query:
{
 "and" : [
 "TaxonKey is Erodium cicutarium",
 "Country is United States of America",
 "HasCoordinate is true"
 ]
}

 The dataset includes 36964 records from 46 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0036357-250717081556266/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.1594/pangaea.941389
title: Temperature and humidity profiles, integrated water vapour and liquid water path derived from the HATPRO microwave radiometer onboard the Polarstern during the MOSAiC expedition

description: The data set contains daily files of path integrated amount of water vapour (precipitable water, prw) and cloud liquid (clwvi), as well as temperature (ta) and humidity (hua) profiles derived from the HATPRO microwave radiometer (see Rose et al., 2005) onboard the Polarstern during cruise PS122 (MOSAiC expedition). The data covers the range October 2019 to October 2020. HATPRO measures atmospheric radiation in seven K band (22.24 - 31.4 GHz) channels, which are sensitive to water vapour profiles, precipitable water and cloud liquid water. The seven V band (51.26 - 58 GHz) channels are sensitive to atmospheric temperature and therefore applicable to derive the temperature profiles. Multivariate regression retrievals have been used to derive the atmospheric variables (see Löhnert and Crewell, 2003, Löhnert and Maier, 2012 and Nomokonova et al. 2019). Temperature profiles have been retrieved from both zenith (mwr00) and boundary layer (mwrBL00) modes. The uncertainties of the variables describe the expected standard error (prw_err, clwvi_err, ...). Each retrieved variable is provided for all available times so that it is up to the user to decide whether or not to use the values if quality flags are set.
DOI: 10.1594/pangaea.972778
title: Cape Horn Current strength over the past 790 kyr from IODP Site 383-U1542

description: Here, we present high-resolution Pleistocene near bottom current strength record based the zirconium to rubidium ratio (Zr/Rb) calibrated with sortable silt data. These records were obtained from International Ocean Discovery Program (IODP) Site U1542, located ~30 nautical miles off the Chilean coast in reach of the southward flowing Cape Horn Current, the northernmost branch of the Antarctic circumpolar current entering the Drake Passage.
DOI: 10.15468/dl.7pz8jj
title: Occurrence Download

description: A dataset containing 0 species occurrences available in GBIF matching the query:
{
 "and" : [
 "TaxonKey is Falcataria moluccana",
 "Country is Timor-Leste",
 "HasCoordinate is true"
 ]
}

 The dataset includes 0 records from 0 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0036358-250717081556266/datasets/export for details.
DOI: 10.1594/pangaea.966225
title: Dissolved radiogenic neodymium, stable oxygen isotopes and rare earth element concentrations of sea ice and snow samples collected during MOSAiC leg 3

description: Ten sea ice cores were drilled close to each other with a Kovacs 9 cm diameter corer (Kovacs Enterprise, Roseburg, USA) on April 8, 2020, near the main sampling site (MCS) for FYI and SYI during leg 3 of MOSAiC (station PS122/3_35-80). The ice cores were immediately transferred into plastic bags and stored at −20 °C together with a snow sample, which was collected before core extraction. In the home laboratory, the ice cores were rinsed with deionized water and the wet top surface was scraped off before the cores were sectioned into 10 cm pieces and the resulting intervals of the corresponding ice core depths were combined. Samples from one sea-ice core were not merged with the samples from the other nine ice cores to investigate the effects of sample pooling and possible related sources of bias. After melting, the meltwater was filtered through 0.45 µm Merck Millipore® cellulose acetate filters. Following homogenization and sub-sampling for salinity and δ18O analysis, the filtered samples were acidified to pH ≈ 2.2 with ultra-pure concentrated hydrochloric acid. Another aliquot was separated for REE and Nd concentration analyses. The snow sample was treated similarly, excluding the deionized water rinse and sectioning steps. The neodymium isotopes are reported as 143Nd/144Nd and as εNd and were determined at GEOMAR using an multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). Their internal and external reproducibility is given in the data table. After pooling, the sea ice samples still had concentrations too low for εNd analysis, so two or three ice core intervals had to be combined to allow determination of εNd with relatively small uncertainties. The repeatedly reported εNd values for individual ice core samples are therefore the same measurement, not the same εNd values measured twice. Rare earth element concentrations are given in pmol/kg and were pre-concentrated offline using a SeaFAST system and determined using an inductively coupled plasma mass spectrometer (ICP-MS) at GEOMAR. Their external reproducibility is better than ~11% for La, Ce, Pr, Nd, Sm and Eu, better than ~13% for Gd, Tb and Dy and better than ~30% for Ho, Er, Tm, Yb and Lu. Stable oxygen isotopes were determined at the Stable Isotope Laboratory of the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University using the CO2-water isotope equilibration technique and are reported as the measured 18O/16O ratio normalized to Vienna Standard Mean Ocean Water (V-SMOV) in δ-notation, with an external reproducibility of ± 0.05 ‰ or better.
DOI: 10.1594/pangaea.972776
title: Sea surface temperature over the past 790 kyr from IODP Site 383-U1542

description: Here, we present high-resolution Pleistocene sea surface temperature record using the alkenone palaeothermometry. These records were obtained from International Ocean Discovery Program (IODP) Site U1542, located ~30 nautical miles off the Chilean coast in reach of the southward flowing Cape Horn Current, the northernmost branch of the Antarctic circumpolar current entering the Drake Passage.
DOI: 10.1594/pangaea.971296
title: Diatom assemblage of the sediment short core EN18232-1, Lake Khamra, Siberia

description: This data set is an extension to the previously published data in a bundled publication (Stieg et al., 2024a) from the Russian Lake Khamra (59.99°N, 112.98°E, 340 m a.s.l.), located in eastern Siberia in SW Yakutia. The short core (EN18232-1) was retrieved in summer 2018 and subsampled in 2021 in 39 continuous 1 cm increments covering the last 220 years (ca. 2015-1790 CE). Detailed information about the age-depth model of the short core EN18232-1 can be found in the research paper (Stieg et al., 2024b). We provide diatom assemblage data for the 39 samples of the short core EN18232-1. We used aliquots of 0.10 g freeze-dried sample material. The slide preparation followed the common procedure (Battarbee et al., 2001). 5 ml of Microsphere suspension (2 x 10^6 microspheres ml-1) were added to estimate the diatom valve concentration (DVC, valves g-1). We used a ZEISS AXIO Scope.A1 light microscope with a Plan-Apochromat 100x/ 1.4 Oil Ph3 objective at 1000x magnification to identify diatom species to lowest possible taxonomic level. We counted a minimum of 350 diatom valves in each sample (mean: 391 valves). To assess the diatom valve dissolution, we determined the F index by dividing the diatom counts into dissolved and pristine categories. The F index has a total range between 0 and 1, whereby 1 equals a perfect preservation. We calculated the diatom accumulation rates (DARs, 10^9 valves m-2 a-1) by multiplying DVC with mass accumulation rates (MAR, g cm-2 a-1), available in a previous published data set (Stieg et al., 2024c), and multiplying it by 100. Additionally, we estimated scales of Mallomonas and Crysophyt cysts without further specification. More details according to the methods can be found in Stieg et al. (in process).